Tandem Mi Engine Build

[DrSarty 90 1 Cars]

1.9 Mi16 3-row ECU's are - 0261 200 158, 161, 167, 354 and 355

 

160 and 162 are 8V Motronic 1.3

 

 

Your groovy gin and tonics seem to have given you OCD Pete! EVERYTHING's in numerical order.

 

 

Just how it should be, which in fact means the 'disease' or 'condition' should really be called CDO.

 

Paul XIII>

Anthony got in with the flywheel just before you I'm afraid. One more of those 3 row ECUs with the above numbers might be useful though. I'm not sure yet which one SorrentoPete has for me.

Edited July 24, 2009 by DrSarty

[Baz 421]

Someone who has one and wants a stonkin' engine put in and can wait 6 months should speak up. It's not going to be given away naturally, but it would save me buying 2 cars/chassis when there maybe 2 out there just needing good engines. Enquiries welcome.

 

I have a shell that'd be ideal for this perhaps.

[crf450 0 1 Cars]

I've weighed the alloy block and liners and a bare cast block and the difference is 16kg.

[DrSarty 90 1 Cars]

I've weighed the alloy block and liners and a bare cast block and the difference is 16kg.

 

Excellent, thanks. So I wonder where the 23kg thing came from then?

 

Baz>

Thanks for your interest too. Gonna be a while, but PM me details, as what you have could be how we choose the second shell. I'm assuming you know where I was coming from and this is a pretty standard shell, with good beam and generally sound overall?

 

Is it 1.6 or 1.9 as the front hubs will be different meaning different sized drive shafts if we don't make the cars the same. The rear beam differences are negligable weight-wise I guess? Sun roof or not, as I believe sunnys are heavier as well as allegedly being less rigid?

[DrSarty 90 1 Cars]

Here's a doodle I did of a possible engine layout to utilise the GTI6 inlet and TB and link it with the Mi AFM and feed it good air.

 

By lowering the rad right down with an 11" pulling Pacet fan (or is it Facet? - I never remember), there'll be a nice area above it and in front of the plenum.

 

If I fabricate an ally heat shield that stops warm air rising up from the rad to the inlet, which also 'scoops' around the back (does a 'reach round' if you like!) to shield both the heat from the engine and force incoming cool air to the underside and rear of the cone filter too, I think it'll be a neater layout. I'd like to avoid 'squished up filter jammed between the battery/washer bottle/headlight' syndrome.

 

Sourcing and fitting the silicon hosing, whether custom (Baker! - Front and centre! ) or even 2 x 90deg bends joined to a 180deg, are the only potential issues, as I'm sure there's room from what I did on my 2.2. A decent bracket could be made to support the AFM.

 

Any comments? (I didn't use a ruler; honest!)

 

Edited July 24, 2009 by DrSarty

[kyepan 291]

a 90 degree bend in a pipe is the equivilent of nearly 17 feet of pipe, or something like that.

 

Plus the radius of the u turn would be non existent, and the AFM would need to be positioned vertically because it is too wide.

 

 

Nice try though.

 

 

i'll be working on an autospeed style custom inlet myself soon, watch this space

Edited July 24, 2009 by kyepan

[kyepan 291]

Pumping loss / flow restriction for different types of bend.

 

note that a sharp 90 deg bend has the worst loss.

Edited July 24, 2009 by kyepan

[brumster 135 1 Cars]

I can't help but think the only way to settle the argument of iron vs. alloy without any way of someone dispelling part of it, is to rig the two engines you build up on an engine dyno and compare them back to back. I understand what you're trying to achieve, but put them in two identical cars and back-to-back compare them, and someone will still shoot some aspect down in flames. "Driver A was slower with the gearchange", or "the weather was different for Driver B", etc.

 

If you just want an excuse to build some cars, though - go for it

 

On the handling side, I'll be able to pass comment towards the end of this year when I drop my iron lump into the rally car...

Edited July 24, 2009 by brumster

[DrSarty 90 1 Cars]

If you just want an excuse to build some cars, though - go for it

 

EXACTLY!!! . I'm really only planning to build the engines. The cars are likely to be someone elses; but that's quite some time away, and may suit someone who has a need for an engine in 5-6months' time.

 

If I really was trying to 'settle' this argument, I'd do it the way you suggested. So I suppose this 'versus' thing is not entirely true from a strictly engine PoV. It's more of a 'how do two more or less identical 205s with these more or less identical engines perform?'

 

My current plan is to abuse my familiarity with Jeremy Clarkson's PA and get Lucinda to get him to let a few of us (naturally the car owners) go down with these cars to the TG test track. Then back to backs - purely for fun as it's always been - could be done where each driver drives each car. A set of averages would show a trend.

 

Justin (Kyepan)>

Hmmmmm. I am sure there is pure fact and logic in that, but allow me to ask something. This is assuming quite rightly that a certain rate of air flow is required, which at best case must match (or slightly exceed to give a margin of error) the potential max flow and air requirements of the Mi head, i.e. at theoretical full tilt @ 250cu ft per min. Is that the correct units and a correct statement?

 

If it is, that is a volume of air at a certain rate, then perhaps (read: I'm sure) there are calculations that could be done to see if even adding a 180 bend in ~72mm internal silicon hose would permit that rate of airflow. Yes it will slow air down travelling through it, but at worse case, with static air (i.e. a stationary car) does it still permit that potential maximum rate of air through? If flow rates approx equate to BHP, then perhaps we only need to allow 200 cu ft per min to leave that margin?

 

So I agree J this approach would slow air down, but would it be sufficiently restrictive to a rate of 250cuft per min through the ~72mm int dia AFM/silicon combo inlet?

Edited July 24, 2009 by DrSarty

[sub205 5]

I'm not convinced there will be any surprise in the outcome of this regarding straight line pace. I think the iron block will be a superior engine, but it will be interesting to see the handling effect of the weight at the front - you may just dispell a myth, or prove it once and for all....

The weight is no problem at all, i recently put a xu10j2 in my 205 ... handles perfectly.

how fast does a car gain 23kg?

 

- abs

- servo

- second fan

- maybe climatic

 

= much more than 23kg.

[kyepan 291]

Hmmmmm. I am sure there is pure fact and logic in that, but allow me to ask something. This is assuming quite rightly that a certain rate of air flow is required, which at best case must match (or slightly exceed to give a margin of error) the potential max flow and air requirements of the Mi head, i.e. at theoretical full tilt @ 250cu ft per min. Is that the correct units and a correct statement?

 

If it is, that is a volume of air at a certain rate, then perhaps (read: I'm sure) there are calculations that could be done to see if even adding a 180 bend in ~72mm internal silicon hose would permit that rate of airflow. Yes it will slow air down travelling through it, but at worse case, with static air (i.e. a stationary car) does it still permit that potential maximum rate of air through? If flow rates approx equate to BHP, then perhaps we only need to allow 200 cu ft per min to leave that margin?

 

i can't believe you're trying to make out that this won't be an issue...

 

 

It will cause drag, therefore restriction at any velocity, the quotient of where and how the drag is produced will change with speed, watch smoke rise, or water flowing around a bridge, looking at the eddies, they will move further from the trailing edge of the surface depending on the rate of flow.

 

You have to remember that the air is also pulsing in the tract, as each cylinder fills and emptys and is not at a constant velocity, put your hand at the end of the exaust if you want an example of the other end, and that's got 10 feet of pipe.

 

Take the time to do the maths and see if it really does make a difference, you've got the volumes of air, can approximate the diameter of the tube and the formula is on the website. off you go.

 

Just remember the subtle 20-30 deg kinks in the spec a inlet manifold on your 2.2 and the 40 horse power they lost you...

 

 

Minor Loss Coefficient - ξ - 90o bend, rounded radius/diameter duct <1 = 0.5

 

 

equation

hminor_loss = ξ v2/ 2 g (1)

 

where

 

hminor_loss = minor head loss (m, ft)

 

ξ = minor loss coefficient

 

v = flow velocity (m/s, ft/s)

 

g = acceleration of gravity (m/s2, ft/s2)

 

Cheers

 

J

Edited July 24, 2009 by kyepan

[DrSarty 90 1 Cars]

i can't believe you're trying to make out that this won't be an issue...

 

I'm not sure I said that J. I actually valued your input and have saved that table to do the calcs purely out of interest.

 

No matter. No arguing on here.

 

What I'm trying to do is visualise the bends and joins used in other engines. 90deg I think is even the rough bend in the standard GTI6 inlet as it goes down towards the airbox (which is mounted quite low) IIRC. There may even be 2.

 

Some inlet manifolds I've seen on other engines, particularly some plastic inlets are almost a complete 180deg. The XU9 inlet tracts are pretty curved and so is the inlet trunking to airbox on 1.6/1.9 8valvers. Also, does the plenum not play a role in smoothing the airflow?

 

I think my inlet improvement came from removing a sharp angle, replacing it with a curve, and upping the diameter from 41 to ~46mm.

 

I'm not disagreeing with you J (me old China) just discussing it. I suppose in short what I'm saying is, is it really that bad with these dimensions and requirements? The silicon internal diameter will be something like 72mm IIRC. The answer could be a simple yes, either mathematically shown or by me getting further advice and recommendations to sack the idea, and that includes you convincing me, as I respect your opinion. This is especially true as I hear you're a diva at Guitar Hero!

 

Taking that a bit further, several airboxes also have angled entries and I agree, that everything in the chain that changes the direction of the air, generating friction against the surfaces and probably turbulence and swirls too that will slow the velocity of the air, which in turn reduces the potential rate of flow of the system. But is that enough to be detrimental to the amount of air I potentially need to flow?

 

I will do the maths as an exercise and look at some other cars with similar ~180BHP outputs and what air inlet routes they have, although I completely agree that straighter and larger is better. The dimensions of the round-to-square route through the Mi AFM will also be a factor, possibly the most limiting one, hence why people remove them in modifications. This IMO is the choke point - the AFM. If any bends thereafter will permit flow better than the AFM then they are not an issue perhaps?

[dcc 855]

I thought the fact that the air and fuel being mixed after the bend in the air tract would not cause any issues, well neglegible anyway...

[DrSarty 90 1 Cars]

This is what I was meaning. A picture paints etc etc...

 

This is my 1.6 (115bhp) and I know the 1.9 (128ish bhp) are the same layout. From the slam panel, you have a small plastic nozzle, going straight along ribbed (sniggers) rubber (sniggers again) at about 70mm internal diameter into the airbox sitting right over the exhaust.

 

There's a 90deg turn there, then out of the air box we have another 90deg and a nearly 90deg of more ribbed rubber before it even gets to the AFM. After the AFM it enjoys another 90deg bend before it gets into the very curved inlet manifold and plenum.

 

On my car there was a lot of room when the GTI6 inlet was fitted:

 

I mean that it's not cramped, and the air flow would be straight into the cone filter, through the AFM, short smooth straight, round one 90deg large diameter silicon bend, short straight again into second 90deg bend and direct into the plenum; an air path of some 2 feet maximum, rather than the 5-6 feet on the above picture.

 

J>

Please don't view this as me arguing with you; I actually agreed with the principle. I'm just comparing it practically to what makes a real-world difference and what doesn't. I know the 1.9 is potentially 60-70 BHP less than these new Mi engines, and that's where a difference may occur.

 

On that basis, I'm quite prepared to experiment and run two back to back tests with this double bend approach and have a straighter, 'behind the headlight' hosing/inlet set-up as well. There may be as per your and the technical advice be a big difference, in which case, I will suck your toes!

[petert 553]

I don't think it will make any difference. Look at the inlet tract on a 1.9L Mi16. Only two things effect inlet performance, CFM and temperature. There will be heaps of CFM. It's far more important to worry about temperature. I guess that's not a problem in the UK though..............

[Batfink 201]

The weight is no problem at all, i recently put a xu10j2 in my 205 ... handles perfectly.

how fast does a car gain 23kg?

 

- abs

- servo

- second fan

- maybe climatic

 

= much more than 23kg.

 

I'm not saying its a problem. I dont think it really is at all. Certainly for a road car I wouldnt even consider it as a concern, but I like a balanced car. Thats why I prefer the 309 handling, and even the XS handling over a 205 GTI

A back to back test is a fantastic way to see if you can notice the difference in the cars poise in certain parts of the corner. Even the wheel choice makes a big difference

[Batfink 201]

This is what I was meaning. A picture paints etc etc...

 

This is my 1.6 (115bhp) and I know the 1.9 (128ish bhp) are the same layout. From the slam panel, you have a small plastic nozzle, going straight along ribbed (sniggers) rubber (sniggers again) at about 70mm internal diameter into the airbox sitting right over the exhaust.

 

There's a 90deg turn there, then out of the air box we have another 90deg and a nearly 90deg of more ribbed rubber before it even gets to the AFM. After the AFM it enjoys another 90deg bend before it gets into the very curved inlet manifold and plenum.

 

On my car there was a lot of room when the GTI6 inlet was fitted:

 

I mean that it's not cramped, and the air flow would be straight into the cone filter, through the AFM, short smooth straight, round one 90deg large diameter silicon bend, short straight again into second 90deg bend and direct into the plenum; an air path of some 2 feet maximum, rather than the 5-6 feet on the above picture.

 

J>

Please don't view this as me arguing with you; I actually agreed with the principle. I'm just comparing it practically to what makes a real-world difference and what doesn't. I know the 1.9 is potentially 60-70 BHP less than these new Mi engines, and that's where a difference may occur.

 

On that basis, I'm quite prepared to experiment and run two back to back tests with this double bend approach and have a straighter, 'behind the headlight' hosing/inlet set-up as well. There may be as per your and the technical advice be a big difference, in which case, I will suck your toes!

 

It doesnt matter though as long as both cars have the same setup We are not trying to make the best engine, but a comparison between two..

Virtually everything bar the engine block itself really need to be the same, 180degree bends or not...

[DrSarty 90 1 Cars]

It doesnt matter though as long as both cars have the same setup

 

I agree from a comparison point of view.

 

We are not trying to make the best engine

 

Oh but I am/we are! The best possible on standard inlet, however that's configured, and minimum budget mods.

 

The Catcam inlet is about £300 new (a paid £140), and the Maniflow or Miles' equivalent is similarly priced new and second hand. I got the Maniflow 4-2-1 off you for £170. The only costly bit really is perhaps the block and liner decking and the engine balance. Everything else can be done on an engine stand in a shed.

 

So on that you can see why this inlet is important and Justin's comments quite valid. The engine bay will be tidier; the air feed will be 'better' and as PeterT says it won't do any harm or make any difference, then unless someone else really warns me off this is what we're going to do.

 

Make no mistake, these are optimised engines. I suspect the only way to get more outright numbers would be to spend £1500 plus on ITBs, an ECU and mapping, to force induction them (which would require a different design approach anyway that we will have already gone passed i.e. high CR) or specialist block and valve-train components to allow for sustained 8,000rpm.

 

This is one reason this is being discussed so openly and freely, to see what else we could do with the limitations of standard inlet components and Motronic management.

[EdCherry 34 1 Cars]

I personally think this should be one step at a time, first of I thought you were trying to optimise the engine, so id start with a plain engine, built and balanced to its optimum.

 

Then id start adding components like the exhaust, the inlet cam so you can give a realistic figure of the gains these modifications add.

 

The same with the intake, modify it after you've got the base engine sorted, it will give you figures to relate to designs.

[maxi 36 1 Cars]

Whats the confusion about? Do people find it impossible to read topics right through and get all the facts????

 

From the outset Rich was going to run, 3 row, 1900 management on both engines. It dosent matter a tupney f*** what each engine had as std, thats whats is going to be used.

 

One point I would like to raise is dump these chips. Std ECU all the way. After all we are trying to compare 2 engines, alloy and solid block as to which one makes makes for a more powerful setup (whether that be torque, bhp, etc). The more they are modified, the more chance we have of the results varying, each engine will react differently to modifications, the more std the setup, the better.

 

Also, those 4 branch manifolds in question foul the bulkhead, ive seen it on cars fitted with them. In some cases Ive seen the pipe bashed so it will clear the bulkhead flange.

 

Maxi

[DrSarty 90 1 Cars]

 

The smiley is to show you that it doesn't matter what's said on here, I'm simply not a grumpy f*ck at the moment because I'm getting some Dutch lovin' over here in Kandahar! (Female before you ask)

 

Perhaps in a way I've misled people, or people (as often happens on here) are either not reading what's written, reading things partially or making their own minds up on what we're doing. I'll come back to the 'we' bit in a minute.

 

You wouldn't believe what PMs have had about this already, concerning who's gonna get a chance to get these engines when they're done and ready to be installed. The simplest answer is money, but added to that the fact that I'd like to see these bad boys go to someone who's less in the limelight and hasn't experienced Mi/GTI6 power before. These should be quite different beasties anyway.

 

So as for 'we'. I' m referring to this as a forum project, but as PeterT and Maxi have picked up on, I'm the tw@ funding it, so they're my engines and I'll do what I damn well pleasey. The forum involvement comes from discussing ideas and making a plan to build the 'best' engines based on the criteria, which in all fairness I never really stated as the engine build was pretty much decided when I chose to do this.

 

Adam offering to do the XU10 installation is great and Pete donating one chipped 3-row ECU is too, and this is when I can see the forum pulling together to get involved in this experiment which will result in participation, discussion, results (?), fun and two highly saleable engines at the end of it.

 

These are not going to be standard engines. Simple. That was never the plan. The high comp and chipped ECUs with a cam was THE decided way from day one to aim for 180BHP. Again simple. I'm not changing this because I trust PeterT and he says this is a guaranteed 180BHP and that's what I want. I have heard of the differences the chipped ECU makes and want a bit of that.

 

What I didn't ever state was any criteria such as using standard parts or keeping price down, for two reasons:

- one was that is was implied anyway by the outline plan I'd written (particularly as there was no aftermarket ECU involved - meaning the chipped ECU was the best way to go to free up the standard management)

- the second was because the engine design was pretty much sorted, although it was open to discussion for other ideas, although NOT to not bother. What would be the point?

 

You may think the last point doesn't leave much room for discussion; well clearly it does.

 

This is not about comparing a standard XU9 and XU10. We could do that any day and could've done it ages ago as there are plenty of candidate cars available.

 

This is about modification and tuning without breaking the bank, of two great engines to make them better by equal mods and budget and see how they fair as engines in similar cars. If it was just the difference of 16kg of iron I could've put 2 car batteries in the passenger footwell in a standard 1.9L Mi'd 205 and raced a 2.0L Mi 205 in fair conditions, swap and record. It's an exercise in pushing the forum's tuning knowledge and seeing new ideas form and hear discussion on how to make things better.

 

Adam>

As for the exhausts, that was only decided as I have a new Maniflow which will go on my 2.2. The Maniflow on the iron block (12mm taller) would definitely foul the bulkhead, you are right. As I have the Maniflow off the 2.2 to use and I know that won't foul the bulkhead on the alloy block, I figured I'd keep things fair and not have to p1ss about reangling stuff by using one of Miles' more suitable 4-2-1 versions. And let's not forget that these really work. Even Jackherer or PugTorque were saying this recently; there is definitely a gain from these manifolds, and therefore it would be wrong IMO to restrict these engines after the other work has gone in. As we said, it's all of the ingredients that make the cake.

 

And what's more, as it seems I'm paying for most of this, gratefully receiving some discount from the kind forum members selling ME the items, then I think it's only fair the final decision rests with me. I am not going to cut any corners on these builds within the constraints of not going silly and keeping with 99% standard management and inlet. These engines when finished should be awesome, but they'll have an anticipated value of £1100-£1400 depending. We shall see.

 

So in short this is my baby and I value your input on ways to do it better. It is not a charity case where anyone's going to get a freebie anything, nor is anyone going to get favouritism. I'm paying a lot of money to do this and expect some payback, both financial and from experience and the reward of completing another challenge. This is for us all to enjoy, and help is most welcome in any form, but please bear in mind all of the above.

Edited July 25, 2009 by DrSarty

[jackherer 543]

And let's not forget that these really work. Even Jackherer or PugTorque were saying this recently; there is definitely a gain from these manifolds

 

There is a reasonable gain compared to the 1.9 manifold, but there is a massive leap in power compared to the 2.0 manifold which is really bad IMO.

 

If you didn't change the original manifolds you really wouldn't be comparing like for like.

[maxi 36 1 Cars]

 

The smiley is to show you that it doesn't matter what's said on here, I'm simply not a grumpy f*ck at the moment because I'm getting some Dutch lovin' over here in Kandahar! (Female before you ask)

 

Perhaps in a way I've misled people, or people (as often happens on here) are either not reading what's written, reading things partially or making their own minds up on what we're doing. I'll come back to the 'we' bit in a minute.

 

You wouldn't believe what PMs have had about this already, concerning who's gonna get a chance to get these engines when they're done and ready to be installed. The simplest answer is money, but added to that the fact that I'd like to see these bad boys go to someone who's less in the limelight and hasn't experienced Mi/GTI6 power before. These should be quite different beasties anyway.

 

So as for 'we'. I' m referring to this as a forum project, but as PeterT and Maxi have picked up on, I'm the tw@ funding it, so they're my engines and I'll do what I damn well pleasey. The forum involvement comes from discussing ideas and making a plan to build the 'best' engines based on the criteria, which in all fairness I never really stated as the engine build was pretty much decided when I chose to do this.

 

Adam offering to do the XU10 installation is great and Pete donating one chipped 3-row ECU is too, and this is when I can see the forum pulling together to get involved in this experiment which will result in participation, discussion, results (?), fun and two highly saleable engines at the end of it.

 

These are not going to be standard engines. Simple. That was never the plan. The high comp and chipped ECUs with a cam was THE decided way from day one to aim for 180BHP. Again simple. I'm not changing this because I trust PeterT and he says this is a guaranteed 180BHP and that's what I want. I have heard of the differences the chipped ECU makes and want a bit of that.

 

What I didn't ever state was any criteria such as using standard parts or keeping price down, for two reasons:

- one was that is was implied anyway by the outline plan I'd written (particularly as there was no aftermarket ECU involved - meaning the chipped ECU was the best way to go to free up the standard management)

- the second was because the engine design was pretty much sorted, although it was open to discussion for other ideas, although NOT to not bother. What would be the point?

 

You may think the last point doesn't leave much room for discussion; well clearly it does.

 

This is not about comparing a standard XU9 and XU10. We could do that any day and could've done it ages ago as there are plenty of candidate cars available.

 

This is about modification and tuning without breaking the bank, of two great engines to make them better by equal mods and budget and see how they fair as engines in similar cars. If it was just the difference of 16kg of iron I could've put 2 car batteries in the passenger footwell in a standard 1.9L Mi'd 205 and raced a 2.0L Mi 205 in fair conditions, swap and record. It's an exercise in pushing the forum's tuning knowledge and seeing new ideas form and hear discussion on how to make things better.

 

Adam>

As for the exhausts, that was only decided as I have a new Maniflow which will go on my 2.2. The Maniflow on the iron block (12mm taller) would definitely foul the bulkhead, you are right. As I have the Maniflow off the 2.2 to use and I know that won't foul the bulkhead on the alloy block, I figured I'd keep things fair and not have to p1ss about reangling stuff by using one of Miles' more suitable 4-2-1 versions. And let's not forget that these really work. Even Jackherer or PugTorque were saying this recently; there is definitely a gain from these manifolds, and therefore it would be wrong IMO to restrict these engines after the other work has gone in. As we said, it's all of the ingredients that make the cake.

 

And what's more, as it seems I'm paying for most of this, gratefully receiving some discount from the kind forum members selling ME the items, then I think it's only fair the final decision rests with me. I am not going to cut any corners on these builds within the constraints of not going silly and keeping with 99% standard management and inlet. These engines when finished should be awesome, but they'll have an anticipated value of £1100-£1400 depending. We shall see.

 

So in short this is my baby and I value your input on ways to do it better. It is not a charity case where anyone's going to get a freebie anything, nor is anyone going to get favouritism. I'm paying a lot of money to do this and expect some payback, both financial and from experience and the reward of completing another challenge. This is for us all to enjoy, and help is most welcome in any form, but please bear in mind all of the above.

 

 

Im out Rich. Sorry. I do apologise for any inconvenience I have caused, I dont think this test is something I fit into. To be honest I dont think this community/cyber world is something I fit into. Im not throwing my toys out of the pram and I wish you and all involved the best of luck but I have made a decision I think would be best for all. As you said the other day on the phone to me Rich, im better off to watch from a far.

 

Maxi

 

Maxi

Edited July 25, 2009 by maxi

[petert 553]

Valve To Piston Clearance

 

One thing you'll to be careful with Rich, is valve to piston clearance. On a 108 deg. centreline, the *526 cam will have approx. 0.090" at TDC, and approaching 0.100" on a 106 centreline. It may well be that something like 110 deg. is best, but if you're going to experiment you need to have the clearance. On a standard XU9J4 there is enough clearance to run up to approx. 0.100" at TDC. Given you'll be decking the block/liners 0.4mm, I'm positive you'll be inside the danger zone and will need to machine the pistons valve pockets accordingly.

 

Even worse for the XU10J4. If you take a 1mm skim off it (I know I would) you'll definitely be heading for a prang.

 

I make these assumptions when allowing 0.080" valve-piston clearance (inlet). The exhaust will be fine as you're using a standard cam. But check it anyway and post the results.

 

So before you assemble the head, do a trial assembly of the blocks after skimming, without rings. If you're unsure of the procedure I can elaborate further when the time comes.

 

Sorry for mixing inches and mm.

 

BTW, the *526 is closer to my Stage II profile. The iron block will be a screamer! It may well run too lean on standard 1.9L injectors. I recently built a 1927cc XU9J4, 11.5:1, Stage I cam and a chipped 3 row ECU. It was running AFR's of 13.1:1 at full load. The iron block is going to out do that.

[DrSarty 90 1 Cars]

That's all clear, excellent advice, and the trial (ringless) assembly technique for ensuring valve issues are avoided were used in my 2.2 assembly and will be employed here too.

 

Everything you've said will be done, including the XU9 0.4mm block and liner deck and the XU10 1mm block deck.

 

Based on the test assy the piston inlet valve pockets will be mod'd accordingly.

 

Three things I'd like clarified please are:

 

XU9:

- after decking, what liner protrusion should I ensure I have in order to bite well into the standard Mi16 head gasket?

- also after decking how will the pistons sit at TDC WRT the tops of the liners , e.g. flush, Nmm below etc?

 

XU10:

- after decking how will the pistons sit at TDC WRT the face of the block, e.g. flush, Nmm below etc?

 

And a 4th Q: are standard Mi (XU9 & XU10 accordingly) head gaskets the way to go here?

 

I know - although I don't fully understand - that cam profile, cam timing, fuel octane and compression ratio (CR) are intrinsically linked. I also know there's more to it than that, but just looking at those in isolation assuming 95RON fuel, would someone please explain something for me? **With the above decks to increase the CR, is it fair to compare the XU9 at 1905cc on 10.8:1 with the XU10 at 1998cc on 11:1 running the same *526 inlet cams?

 

I'm not making a big deal of it, as I think we're agreed that the standard engine test XU9 vs XU10 in outright power would favour the iron block anyway.

 

What I'm asking is would these mods make the gap even bigger? I don't care if it does, but the iron block had an advantage anyway, and will get what I perceive as an additional CR advantage with these engine mods here too. And with my lack of understanding of the relationship in the question marked ** above, I'm not sure what sort of advantage that really means. This is implied by you saying the XU10 will be a screamer, but I'd really enjoy having it explained.

 

I'm really excited about seeing the two power curves overlaid to compare these two engines.

 

Then I'm also excited to see if the lighter XU9 engine, with an "under square" piston:stroke ratio (83x88mm) makes the engine behave differently as it may well have better low engine speed torque, compared to the dead-on square ratio of the XU10.

 

And whether the 16kg weight differential makes any difference going into, through and out of corners.

 

And whether the XU10's most likely extra grunt from higher CR and 100cc more diplacement compensates for the weight difference. The XU10 being squarer (or in fact square at 86x86mm), I think is what Pete means by 'a screamer' despite the larger displacement. Whereas the XU9 with the longer stroke by comparison to bore might be the lighter thumper. (?)

 

Any comments?

 

As you can tell: I'm excited.

 

'Tis an adventure, and an adventure that I'd rather see you back in Adam (Mr Maxi), whether you install an engine or not.

 

Interesting comment on the injectors. What is the peak capacity at 80% duty cycle of the Bosch yellows then? Perhaps we need GTI6 greens on the XU10, although that's then changing things a lot perhaps, as they have a better spray pattern I'm led to believe. Could both cars run the GTI6 injectors if this was required perhaps with lower fuel pressure on the XU9? Injectors are still black magic to me.

 

Info links for people learning, which includes me:

 

http://en.wikipedia.org/wiki/Crank_shaft (my piston stroke comments are based on this - scroll down to that section)

 

And a pretty pic:

 

 

BTW if anyone's interested in PeterT's stage I inlet cam regrinds they are only $175 AUD including return shipping (that's £87 !!! - exchange item). Bargain.

 

I will be needing a second *526 Catcam if someone has one? I'm going to ask Batfink and Matt at QEP if they can do a special, even on a used one.

Edited July 26, 2009 by DrSarty