Changing The Mi16 Engine Characterists.

[jonD6B 0]

Alot of interesting answers but just to reiterate the question; what is involved in increasing low down power and torque on the 16V engine without losing too much top end power? It's not a play off between how much power/torque each engine has against the other at any given rpm, it is a case of seeing if you can have the 16V refinement, power and modernised set up but give it the characteristics of the 8V which alot of us like.

[huxley309 0]

Simple fit bodies/carbs you gain top end and low/mind end too

[Super Josh 4]

Here's a graph of my current Mi16 on bodies forged pistons, Maniflow 4-2-1 manifold & BV head compared to my old 8v SBC 1.9GTI-S (cams & headwork).

 

The spikey bit at the end of the Mi16 power figure is due to noise interference.

 

 

Rob, what gearbox are you running?

 

 

 

 

Josh

[mfield 20]

You will love an mi on bodies it makes them much more driveable and fun!!

 

You gain power thoughout the whole rev range but mainly in the lo-mid end where mi's seem to lack

 

If you ever see my 309 at a meet ask me for a spin i promise you won't be disapointed

 

 

After looking at the replies regarding the revised manner's of the mi after bodies/carbs fitted it will be a passenger ride im looking forward to

[Robsbc 0 1 Cars]

Rob, what gearbox are you running?

Josh

 

Both me and Revla run 1.6 gearbox

[JERAM 0]

Thats a pretty impressive result Jeram, didn't realise it was that good!

Does the blue line show the same engine without the carbs, or just without the cam swing?

 

same engine, same set-up, just dialing the cams to get rid of the flat mid range.

 

the engine was rebuilt but had no performance parts fitted appart from ARP rod bolts, std valve seats etc.

 

i settled for a loss of 28 bhp in the end, to gain the grunt at the bottom end. the more the hp went up the more the torque went the other way

[Shevy 4]

I've also attached my friend Revla's graph of his 2.0 S16 on Catcams, bodies, 3 angle valve seats & GTI-6 manifiold versus the old set up using the AVAC system.

 

Rob, do you know what model Catcams Revla was running to produce that power ?

[Robsbc 0 1 Cars]

Rob, do you know what model Catcams Revla was running to produce that power ?

 

Wildest cams you can fit using hydraulic lifters....

[alternative 0]

you've got to remember that the 205 I took you out in was stripped with no soundproofing and had a bit of a hole in the exhaust!

Like I said when I saw you, that wont help at all, it'll just make it flatter if anything I would have thought.

 

However, having met you and your pug I dont think an Mi16 is right for you after all, I think you'd be pleased with a nice rebuilt 8v and you'd do well to run it on some better management (either an AFM/distributor-less system from a newer peugeot or an aftermarket ECU) for reliability and smoothness.

 

Your CTI is very nice btw, and will continue to be whatever engine you go for (any chance you can post some pics? I'd like to see what people have to say about the colour cos its a new one on me...)

 

 

you've got to remember that the 205 I took you out in was stripped with no soundproofing and had a bit of a hole in the exhaust!

Like I said when I saw you, that wont help at all, it'll just make it flatter if anything I would have thought.

 

However, having met you and your pug I dont think an Mi16 is right for you after all, I think you'd be pleased with a nice rebuilt 8v and you'd do well to run it on some better management (either an AFM/distributor-less system from a newer peugeot or an aftermarket ECU) for reliability and smoothness.

 

Your CTI is very nice btw, and will continue to be whatever engine you go for (any chance you can post some pics? I'd like to see what people have to say about the colour cos its a new one on me...)

[Shevy 4]

Wildest cams you can fit using hydraulic lifters....

 

Cool, should mean I will be putting out in excess of 200BHP with my new setup.

Matt is gonna fit a set of cams one stage further up than them in my new engine.

[Robsbc 0 1 Cars]

Cool, should mean I will be putting out in excess of 200BHP with my new setup.

Matt is gonna fit a set of cams one stage further up than them in my new engine.

 

R u sure they are not the same as Revla's as next one's up are for solid lifters...

[Shevy 4]

Yeah, I'm pretty sure

 

Everyone that is running the Biggest Cat Cams on hydraulic lifter are running the one's with 11.5mm of lift.

All the big capacity bottom ends bring down the RPM where peak power is.

Matt Said I could go up another Cam due to this but he is going to have to modify my new high comp pistons to accomodate the new cam. Matt will probably read this, hopefully he will explain.

Edited March 30, 2006 by Shevy

[Robsbc 0 1 Cars]

Ah ok then....

 

I expect you to be around the 220BHP plus mark based on Stew205 who has a 2.1 bottom end and cat cams

plus forged pistons. His made 218BHP & 173lbft on a dyno (not rolling road).

 

Now your previous engine before it had head issues you quoted 180lbft on Owens rolling road which look way too high for a 1.9 Mi compared to Stew205. Your new engine will be much closer to that torque figure.

 

Forged piston with increased oil consumption expect 1 litre of oil useage for 750-1000 miles.

Edited March 30, 2006 by Robsbc

[alternative 0]

you've got to remember that the 205 I took you out in was stripped with no soundproofing and had a bit of a hole in the exhaust!

Like I said when I saw you, that wont help at all, it'll just make it flatter if anything I would have thought.

 

However, having met you and your pug I dont think an Mi16 is right for you after all, I think you'd be pleased with a nice rebuilt 8v and you'd do well to run it on some better management (either an AFM/distributor-less system from a newer peugeot or an aftermarket ECU) for reliability and smoothness.

 

Your CTI is very nice btw, and will continue to be whatever engine you go for (any chance you can post some pics? I'd like to see what people have to say about the colour cos its a new one on me...)

[alternative 0]

First two apologies - I'm not very good at working the knobs and buttons on the forum. Second, an apology to Jackherer - I immensely enjoyed our spin round the ring roads of Chelmsford and blowing off the MX8. Anyone who wants a good afternoon speak to Jackherer nicely and bring your brown trousers...

I'm not suggesting the Mi16 is not powerful, it is. Old fogeys like me remember the driveability (a forgotten word)of the Lotus twincam. Another example is the grunt out of the corners of a V twin Ducati (I used to race one in club events) which for years beat the Jap multicylinder mulitvalves.

Petert, youre absolutely right, I do have a 105 bhp 1.9 in my CTi and it does peter out above 3000 or so. The trouble is all the power is so available from tickover it will leave behind many things in London where the next corner is only 30 yards away so I have to consider carefully anything which makes the power less available. I'd love to fit an Mi engine just for the technical pleasure of a twin cam and those lovely magnesium cam covers but I'd like not to lose the instant pickup of a torquey engine. Perhaps I could PM you about that offest cam sprocket arrangement.

All in all its a fascinating discussion but I still feel powers no good if you nearly have to wring your engines neck to get it.

Jackherer, actually I can drive fast - I think you're just trying to get your hands on my 2000 mile Mi engine!

[Shevy 4]

Ah ok then....

 

I expect you to be around the 220BHP plus mark based on Stew205 who has a 2.1 bottom end and cat cams

plus forged pistons. His made 218BHP & 173lbft on a dyno (not rolling road).

 

Now your previous engine before it had head issues you quoted 180lbft on Owens rolling road which look way too high for a 1.9 Mi compared to Stew205. Your new engine will be much closer to that torque figure.

 

Forged piston with increased oil consumption expect 1 litre of oil useage for 750-1000 miles.

 

I hope to be around that region.

With my big valve head Matt has made 30% increase of flow at low lift going up to 12% at high lift with 36.5mm inlet valves.I've no idea how this effect my over bhp and torque figure but it's an increase at the end of the day which has got to be good.

 

My old head gave a very strange output on Owens rollers which are supposed to be very accurate,although it was never fully mapped properly due to some problems I had.Anyway what matters now is the results from my new engine. If I achieve around 220bhp and 170 lb ish of torque I will be well happy

My original engine I started with was supposedly 208bhp and 160 lbft torque on John Wilcox rolling road with the printout I had,but I've no idea how accurate their rollers are.

At the end of the day the rollers only give me a rough idea of the performance of the engine.

If it's good on track I'll be happy.

Speaking of track days the wife is paying for some track tuiton for my 30th birthday in May, so I've got to have the car fully run in and all setup by then !!!

 

In the mean time I will get shares in some local oil company !!

[sorrentoaddict 1]

 

I'd WALK 2,000 miles for a 2,000 miles MI-16

 

[petert 550]

I'd love to fit an Mi engine just for the technical pleasure of a twin cam and those lovely magnesium cam covers but I'd like not to lose the instant pickup of a torquey engine. Perhaps I could PM you about that offest cam sprocket arrangement.

All in all its a fascinating discussion but I still feel powers no good if you nearly have to wring your engines neck to get it.

 

Despite only having 105hp, the CTi (DFZ) engine is very crisp due to it's small piston squish height. I like to do the same to Mi16's when I rebuild them and the difference is quite noticeable. The CR increases to 10.8:1 and they have a crisper note. I can't see why a 16V can't have the same neck snapping torque off idle if built properly. Torque is what makes car accelerate quickly, not reving it's neck off. The quickest 205 track car in Australia (not mine unfortunately) has a very well sorted 16V which makes a truck load of torque from 4500-6000, and is rev limited to 7200, running a 4:06 diff. The same guy speciallises in building Lotus twin cams incidently.

 

The offset key is a simple solution to finding torque. Some people like to spend hundreds on vernier pulleys, when all they need to is change the key and/or fit a different pulley. There's no point in moving (or changing) the exhaust cam on engines up to 200hp, so fitting a vernier here is a waste of money. There are three different inlet pulleys, which were fitted to different variations of the XU9J4. The inlet lobe centre lines go like this:

 

#2 - 114 deg.

#3 - 111 deg.

#4 - 108 deg.

 

Moving the inlet cam to 109 - 106 deg. gives a much broader and useable power range. Fitting a 4 deg. offset key with a #3 pulley gives 107 deg.

 

Jeram's two graphs perfectly illustrate what happens. I personally wouldn't advance the inlet as far. He could even iron out that dip at 3500-4000 if he maps the ignition correctly!

Edited April 1, 2006 by petert

[SweetBadger 91]

Despite only having 105hp, the CTi (DFZ) engine is very crisp due to it's small piston squish height. I like to do the same to Mi16's when I rebuild them and the difference is quite noticeable. The CR increases to 10.8:1 and they have a crisper note. I can't see why a 16V can't have the same neck snapping torque off idle if built properly. Torque is what makes car accelerate quickly, not reving it's neck off. The quickest 205 track car in Australia (not mine unfortunately) has a very well sorted 16V which makes a truck load of torque from 4500-6000, and is rev limited to 7200, running a 4:06 diff. The same guy speciallises in building Lotus twin cams incidently.

 

The offset key is a simple solution to finding torque. Some people like to spend hundreds on vernier pulleys, when all they need to is change the key and/or fit a different pulley. There's no point in moving (or changing) the exhaust cam on engines up to 200hp, so fitting a vernier here is a waste of money. There are three different inlet pulleys, which were fitted to different variations of the XU9J4. The inlet lobe centre lines go like this:

 

#2 - 114 deg.

#3 - 111 deg.

#4 - 108 deg.

 

Moving the inlet cam to 109 - 106 deg. gives a much broader and useable power range. Fitting a 4 deg. offset key with a #3 pulley gives 107 deg.

 

Jeram's two graphs perfectly illustrate what happens. I personally wouldn't advance the inlet as far. He could even iron out that dip at 3500-4000 if he maps the ignition correctly!

 

Hmm, I have a #2 and #4 pulley with the MI I've just rebuilt, I'm sure I read on here somewhere and on the peugeot build manual that the #2 pulley is for the inlet cam.

 

The place that skimmed my head skimmed a lot (too much!) off it so I will have high compression - is it worth swapping #4 to the inlet and #2 to the exhaust before I drop it in...is that how they're supposed to be anyway?

Edited April 1, 2006 by SweetBadger

[petert 550]

Definitely use #4 on the inlet and #2 on the exhaust. I never use a #2 on the inlet. It's too retarded for a performance cam.

[Rom 0]

I tried a search about the pulley keys, and diff pulleys. But came up empty.

Is there a thread explaining this in depth ? As im not quite following it all yet. I understand there are different pulleys. How can they be told apart,and these offset keys. Are they std,custom,off the shelf etc.

[petert 550]

The inlet lobe centre line is the maximum opening point of the valve, in degrees after top dead centre. So a 111 deg. centre (#3) is advanced 3 degrees (crank) more than a 114 deg. centre line (#2). The number is cast into the pulley. It's very difficult to actually see the difference in the pulleys without a jig, or measuring them. The three different pulleys are all PSA original parts. Most Mi16's have a #2 on both the inlet and exhaust. The offset keys are custom parts available from me. I'm not aware of anyone else who has them.

Edited April 2, 2006 by petert

[Anthony 1,000]

Is there any big disadvantage to advancing the inlet cam a few degrees, besides the slight loss of top end?

 

Just seems strange to me why Peugeot didn't build them all with #4 pulleys judging by the difference advancing the cam timing looks to have made on JERAM's dyno run and from what you're saying Peter. Does it increase emissions or not work particularly well with the standard inlet manifold, or something like that which would be important to OE manufacturers but less so to the likes of us?

 

Certainly most of the XU9J4's I've seen here in the UK have had #2 pulleys on both inlet and exhaust.

[PumaRacing 1]

I am thinking of fitting a 16v in a CTi with a much reduced compression ratio to make it more flexible and able to pull a higher final drive. I am also considering moving the servo so one can use much more flexible engine mountings all round so as to isolate the effect of high revs and enjoy smoother running. I would personally not fiddle with the valve timing if flexibility is the aim. Could I suppose, try a heavier flywheel! Interested to hear what everyone thinks!

 

I think you have no idea how engines work.

 

If your ideas how to improve the low rpm power of an engine are to 'reduce' the compression ratio and fit a heavier flywheel then you're in for some serious disappointments.

[petert 550]

Is there any big disadvantage to advancing the inlet cam a few degrees, besides the slight loss of top end?

 

Just seems strange to me why Peugeot didn't build them all with #4 pulleys judging by the difference advancing the cam timing looks to have made on JERAM's dyno run and from what you're saying Peter. Does it increase emissions or not work particularly well with the standard inlet manifold, or something like that which would be important to OE manufacturers but less so to the likes of us?

 

There's really no disadvantages for most applications. The increase in torque certainly outways the decrease in top end.

 

The lobe angle originally determined would have been chosen in combination with several factors - rod angle, inlet runner volume and CR. Keeping the angles wide also minimizes overlap, improving idle quality, emissions and fuel economy.

 

I only saw a #4 pulley for the first time a few months ago. I'm not sure what car it came from.