Finally Mapped

[Rob Thomson 6]

I believe you are an intelligent individual Rob and have a lot to contribute, I just wish you'd reign in some of that attitude.

Attitude? I just asked a few pertinent questions, but if that's rude then I'm so terribly sorry.

 

By the way, what happened to the Capricorn "war"? Found any more bulls*it videos on YouTube recently?

[Rob Thomson 6]

Fun doesn't necessarily mean fast. Yes keeping it in the boil absolute;ly can be fun and a good challenge, but like I said that may be tiresome on a circuit, and in some circumstances that narrow powerband makes you slower.

This isn't really relevent to the thread, but could you remind me why you think speed is so important given that you only do non-competitive track days rather than actually competing?

 

So while some people rant and rave at other people because they dont subscribe to the conventional (or popular) wisdom that big bhp means fast lap times (in isolation), I certainly don't think that's mature behaviour.

So actually understanding what makes a car fast isn't mature? Ok, let me erase all my knowledge of really basic physics and engineering and come back to this thread when I'm synthetically retarded.

 

A 16V developing 230bhp is always going to be faster than an 8V developing 200bhp just so long as that 16v develops a reasonable spread of power over a couple of thousand rpm, which of course it will.

Edited February 3, 2007 by Rob Thomson

[DrSarty 90 1 Cars]

This thread>

the technical bits are good stuff, and thanks to those who list their mods (which they could keep secret) as it helps us dreamers plan what we might do next. I'll add here that what we decide to do should absolutely relate to what application/use we have planned for the car.

 

Stuff like this>

Attitude? I just asked a few pertinent questions, but if that's rude then I'm so terribly sorry.

 

By the way, what happened to the Capricorn "war"? Found any more bulls*it videos on YouTube recently?

 

Hmmm....firstly if only that were a genuine apology. They may be questions you ask but they tend to be laced with hemlock! The Capricorn 'war' comment was because (as usual) your prompted recent replies were equally bitter and aggressive and shall we say "gripped my sh1t!". Just re-read and assess the tone of your last quoted line ^^^ above.

 

I was thinking not to bother because you are quite obviously not a man to be reasoned with. However, although things like getting ready to go to Afghanistan in 7 days are interfering with daily forum life , as I've seen PDF file attachments in this thread I will add to Capricorn soon as promised. I think my document shows a fair analysis of the whole thing. Could you possibly also contemplate that uTube is just a media outlet, nothing else, and as such nothing dictates that the content is bullsh1t.

 

Returning to this thread for a question;

 

which component ultimately affects the delivery of the torque curve? Eg, is it a certain cam shaft that means the torque increases at say 4.5k or is it a fuel delivery or air flow at speed issue. I appreciate an engine is a blend of many components but ultimately the process is simple enough; why does the torque curve have the shape it does, and what altered components change it in what fashion?

 

Just wondered.

[PumaRacing 1]

A 16V developing 230bhp is always going to be faster than an 8V developing 200bhp just so long as that 16v develops a reasonable spread of power over a couple of thousand rpm, which of course it will.

 

Absolutely, especially as the 8v isn't even going to have 200 bhp! There's no comparison and frankly no contest between an 8v and 16v engine from the same family and of similar capacity. It doesn't matter how you tune the 8v, it'll never have as much power, as much torque per litre or as wide a spread of power at the same bhp level. Unless class rules mandate it I can't understand why anyone would waste their money trying to extract very high bhp from an 8v rather than getting either the same bhp with a better torque spread from a 16v one or a lot more bhp with a similar torque spread.

 

It's interesting, to me anyway, running the maths of how 8v and 16v engines compare. Firstly the extra valve area of the 16v translates directly into the same percentage power advantage. Secondly the 16v has 41% more valve circumference for a given valve area than the 8v which means a lot more low lift flow. That together with the better swirl and burn add another 10% power advantage. The OP's engine makes a nice comparison with a 43mm valve 8v engine running similar cam duration and TBs that's been mentioned on here quite a lot. Let's compare.

 

The difference in valve area is (34.6 squared x 2) / (43 squared) = 1.295

 

Multiply by a further 10% for the low lift flow, swirl etc = 1.424

 

There's also a small difference in cam duration, 255 degrees in the 8v and 252 in the 16v. We can allow for that too.

 

So if the 16v produced 232 bhp the 8v ought to have 232 / 1.424 x 255 / 252 = 165 bhp

 

Well fancy that Actually there should be a further factor for the lower capacity and lower CR of the 8v in question but then maybe my cylinder head work made up for that

 

What also could have been done to the 16v engine to make a very cheap conversion would be to retain the standard cams therefore no need for the forged high comp pistons. Keeping the cylinder head work, good exhaust system and the TB's, adding a little CR by skimming the block and the power drops to a tad under 200 bhp and the engine pulls from tickover. To get the 8v even close to that means a violently unpleasant camshaft and no power under 5k.

 

As far as alloy and iron blocks go it's the latter every time for me. In engineering terms the wet liner alloy block is something of an abortion. It saves a little weight but adds a number of problem areas.

 

1) Sealing the liners to the bottom of the block so the coolant and sump oil don't mix.

 

2) Sealing the head gasket when the liners protrude and not even necessarily by the same amount on each liner unless you blueprint everything very carefully, and even then you have a weakened seal round the outside of the block tub itself compared to an engine with a flat block face.

 

3) Liners shuffling against the head gasket.

 

4) Liner ovality and blow-by due to piston forces.

 

5) No easy way to add capacity cheaply and easily by overboring.

 

6) No easy way to change squish or CR by skimming the block.

 

7) Block corrosion problems. I reckon to scrap half the XU blocks I strip down due to corrosion where the liner seals go or in one particular spot on the side of the block where I guess the coolant stagnates.

 

Frankly a one piece solid iron block makes everything so much more sturdy, gives the head gasket a much easier time and makes the engine build quicker, easier and cheaper. In the case of the XU it's an even easier decision because the iron block has more capacity to start with.

 

Even with the 1360 TU where there are alloy and iron blocks of the same capacity I'd choose the iron one every time.

 

You only have to look at the Rover K series engine to see what a nightmare a badly designed wet liner alloy engine can be. You also have to ask yourself why with weight saving, fuel economy and emissions such a factor these days Peugeot reverted to 'old fashioned' iron blocks for the later XU engines.

 

There 'are' good ways to design alloy block engines but they don't involve wet liners. Nikasil bores give you the weight saving of alloy with the solid one piece design and strength of iron blocks. Unfortunately you can't skim them, rebore them or even rehone them without specialist equipment so modifying them isn't an easy proposition. I once had someone bring me a cylinder from a single pot Yamaha bike engine to skim. I didn't realise it was Nikasil until I tried to skim it and the carbide cutter just bounced off when it got close to the bore walls. I had to finish it off against a sheet of wet and dry paper on a surface plate to get the bugger flat again. Still, at least I won't get caught out like that a second time.

[maxi 36 1 Cars]

Absolutely, especially as the 8v isn't even going to have 200 bhp! There's no comparison and frankly no contest between an 8v and 16v engine from the same family and of similar capacity. It doesn't matter how you tune the 8v, it'll never have as much power, as much torque per litre or as wide a spread of power at the same bhp level. Unless class rules mandate it I can't understand why anyone would waste their money trying to extract very high bhp from an 8v rather than getting either the same bhp with a better torque spread from a 16v one or a lot more bhp with a similar torque spread.

 

 

I think this is a very important statement spoken from experience.

 

Maxi

[maxi 36 1 Cars]

Just looking at my power graph, a little post of my torque figures per 500RPM....

 

1500-80

2000-105

2500-120

3000-125

3500-140

4000-152

4500-160

5000-165

5500-170

6000-174

6500-170

7000-160

 

Engine made 216BHP @ 6720RPM with peak torque at 5700RPM.

 

Maxi

[Robsbc 0 1 Cars]

I think Mos's car has had very little headwork like 3 angle valve seats...Might be wrong..

[smckeown 1]

could you remind me why you think speed is so important given that you only do non-competitive track days rather than actually competing?

 

1 - To leave the door open for competition - i'm hoping to get involved this year

2 - I'm a weight saving junkie

3 - I'd rather a reasonable powered minimum weight (to within reason) car rather than a heavier big bhp motor; just my my reference

 

So actually understanding what makes a car fast isn't mature? Ok, let me erase all my knowledge of really basic physics and engineering and come back to this thread when I'm synthetically retarded.

No you're not getting the point. I said people why rant and rave at others who dont share the same opinion, especially when they cant expalin the logic is what i find immature

 

A 16V developing 230bhp is always going to be faster than an 8V developing 200bhp just so long as that 16v develops a reasonable spread of power over a couple of thousand rpm, which of course it will.

 

Ah now that's more like it (the end bit is important), Ceteris paribus. I would prefer the first engine, as the pwer would shift a few thousant RPM down the range and suit my needs better.

 

Interesting stuff from PR, but the maths don't quiet stack up when there are plenty of 190bhp 8v's around. But a good read all the same. Good to get a pro's view.

[veloce200 3]

Currently there's a rash of switching from Alloy to Iron in the Sprint/Hillclimb cars down here.

but how do they get away with using a block of the wrong material ? strictly speaking in a 205 you can only use alloy? I know in TRC someone used iron and they are now changing regs to allow it's incorporation

[Robsbc 0 1 Cars]

Just looking at my power graph, a little post of my torque figures per 500RPM....

 

1500-80

2000-105

2500-120

3000-125

3500-140

4000-152

4500-160

5000-165

5500-170

6000-174

6500-170

7000-160

 

Engine made 216BHP @ 6720RPM with peak torque at 5700RPM.

 

Maxi

 

What trumpets length did you use Maxi?

[maxi 36 1 Cars]

What trumpets length did you use Maxi?

 

Very short, something like 45mm?

 

Cant actually remember now. I wasnt fussed about torque at all, I just wanted peak BHP.

 

Maxi

[veloce200 3]

A 16V developing 230bhp is always going to be faster than an 8V developing 200bhp just so long as that 16v develops a reasonable spread of power over a couple of thousand rpm, which of course it will.

 

assuming the cars weighed the same, and all other things were equal, then YES. the point is people are underestimating just how much faster you can turn in and and exit a corner with a significant weight advantage of a basic alloy 8v versus and iron 16v. It makes me laugh when people slate the K-Series - it is one of the most clever engines of recent years - why do you think Caterham used it? Granted if put together badly it's not reliable but most Lotus owners agree a significant on track speed advantage with K Series power EVEN with less power than eg Honda/ Toyota conversions.

 

for example look below and tell me which one you think would be quicker - no contest right?

 

4 wd turbo 960 hp, bhp/ton = 738

2wd atmo 115 hp , bhp/ton = 328

[Sandy 189]

but how do they get away with using a block of the wrong material ? strictly speaking in a 205 you can only use alloy? I know in TRC someone used iron and they are now changing regs to allow it's incorporation

A vast proportion of all the 205s produced had an Iron block XU.

[veloce200 3]

A vast proportion of all the 205s produced had an Iron block XU.

the diesel block? not the same though is it?

[Sandy 189]

Nope, it's 83mm, but if you get the right casting it can be bored to whatever like the 2.0 litre petrol.

[Mattsav 1]

You think? All they have done QEP/DES taken some off the shelf cams, fogred pistons and put some 3 angle valve seats. Nothing that nobody else couldn't do now by ordering those bits. Obviously they have chosen wisely regarding the cams...And well down to them!

 

Long term will these engines still be running 100% with 60K on them? I know the SBC conversion I have is reliable as DAZ_C has one which has covered 60,000 miles and he drives like Maxi and he kept up with my 3.5k engine last January. I also know of another SBC customer Robin Sweet with similar mileage.

 

Only today I got told by someone who went down the JE 85mm pistons and liner route his rings went after 1,000 miles. glad I didn't go down that route as SBC weren't keen on it as it was proven in their eyes.

 

Rob

 

Yep we just bolt them together.

However in 1300 Vuaxhall Nova stock rods you have a couple of paragraphs of what you are and are not allowed to do along with specific sizes for some parts. Everything else is banned.

 

The last engine webuilt went on the rollers the same day as the class champion and had 8bhp more.

 

Same engine, same rules. The previous years engine (in a different class) also won the championship.

On track it happily laps faster than the other and pull sout fo the corners much better which is where it counts.

 

We will get a whole season of 'Thats a bent engine mate'. Then it will be sealed, stripped and he'll keep the trophy (assuming he keeps the car in something like one peice, half way through last season the car needed re shelling after 5 cars and a peice of Armco shortened it!)

 

Another driver who had a quick 1.3 vauxhall engine built by us. The next year he was tempted by an expensive engine from the so called experts and spent the year running at the back.

He brought this engine to us to rebuild and it ended up getting weighed in for scrap.

We built another from scratch and was leading the class until he got stuffed into the armco and a following car ran into the back of him. Unfortunatley he's lost his bottle after this and doesn't race any more.

 

I really like building these basically standard engines as they really get you thinking about how to optimise them within the rules. There's no challenge to building a 'Bent' engine.

 

 

Richard Simmons has won the last 4 series he's entered with our engines in various classes and specs.

We hope to do the same this year, after we've bolted the engine together!!

 

2 out of the other 3 engines we've re built are going well in this class. The third had a carb fall off (not put on by us) and melted a piston.

 

If people want to build there own then no problem. Give me a bell and I'll happily supply the parts.

 

Is the engine a success?

Mos told us what he wanted and what he was going to use it for, we quoted it, built it and it does exactly what he wanted. So another successful build!

 

The more airflow you have the better the engine you'll get. If have lots of airflow and big capacity then thats the ideal combination.

 

If someone wants a turbo engine, 16v or 8v then we will build it. What engine you go for is personal choice, I just try and advise what will give the best results for the budget and the type of use its going to get.

 

 

The rest of the 8v/turbo/16v bickering is just pointless.

[PumaRacing 1]

assuming the cars weighed the same, and all other things were equal, then YES. the point is people are underestimating just how much faster you can turn in and and exit a corner with a significant weight advantage of a basic alloy 8v versus and iron 16v.

 

It's all relative to the weight of the vehicle. What we're talking about with the TU and XU is 15 or 20 kg in an 800kg tin top. It's only about 2% of the vehicle weight. Bugger all basically. It's the same weight as 5 gallons of petrol. Who thinks they can actually discern a speed or handling difference in their car when it has a full tank or a half full tank?

 

It's a completely different issue for an ultra light car or single seater with a range of engine choices where the weight difference can be 50 or more kg. Maybe even 100 kg if bike engines are brought into the equation. The engine weight difference can be 10% or even 20% of the vehicle weight and that's enough to make a huge difference. One of my hillclimb customers runs a bike engined Mallock which weighs 330kg. In fact I think that's with him in it too but I'd have to check. If he swapped to a Vauxhall XE engine and box (quite a popular engine on the hills) weighing over twice what the bike engine does he'd need a shed load more bhp just to go as fast as it does now.

 

However, if anyone with a tin top is concerned enough about weight to choose an alloy block XU over an iron one with the bonus of more capacity it begs the question were they concerned enough about weight distribution to move the battery into the boot? If not then there's no real logic to the engine choice.

[PumaRacing 1]

I really like building these basically standard engines as they really get you thinking about how to optimise them within the rules. There's no challenge to building a 'Bent' engine.

 

It's actually often more challenging and expensive to build a winning 'stock' engine than a fully modified one. Somewhat perverse as the regs are supposedly to keep costs down. It involves microscopic detail in the blueprinting, lots of flow testing to find the best stock bits, even more flowtesting to find out how optimised valve seat profiles and widths can squeeze a bit more flow out and all to get a few extra bhp which can make all the difference when the cars are basically the same.

 

Fully modified engines are often easier because if you really know your porting work you've got a big advantage over most of the other ported cylinder heads out there to start with.

 

Another driver who had a quick 1.3 vauxhall engine built by us. The next year he was tempted by an expensive engine from the so called experts and spent the year running at the back.

He brought this engine to us to rebuild and it ended up getting weighed in for scrap.

 

The old grass is greener on the other side syndrome. 15 or so years ago I had a customer in the Mg Maestro Challenge. I did his head work for a couple of years and according to the rollers that looked after quite a few of the people in that series it was well ahead on power. However there was one guy he could never beat and usually came second to this guy's first. Clearly it couldn't be the other guy's better driving, perish the thought, so it had to be bhp. I wondered what had happened when I didn't hear from him for a while. He'd jumped ship to the other guy's engine builder, lost 10 bhp, got too embarassed to come back and tell me and gone to a third engine builder to try and recover the losses the second one had created.

 

I found out by chance because I knew engine builder 3 anyway and dropping in unannounced one day for a chat found him and my ex customer deep in study over a Maestro cylinder head. There were red faces for a while. It transpired that engine builder 3's attempts had recovered some of the power but the thing kept blowing head gaskets and they couldn't work out why. One squint at the ploughed field finish on the head face was enough to know the answer to what had stumped them for a season. I left them to it. It seemed like fairly poetic justice. The guy at the rolling road kept me posted for a while. They never did get all the power back and even when it didn't blow up in a race it was never as competitive as he had been in the past. C'est la vie.

[boombang 2]

You think? All they have done QEP/DES taken some off the shelf cams, fogred pistons and put some 3 angle valve seats. Nothing that nobody else couldn't do now by ordering those bits. Obviously they have chosen wisely regarding the cams...And well down to them!

Furthermore to Matts reply above.

 

Stock hatch is an amazingly competitive class, however a DES Developments powered 205 Gti 1.6 has been crowned BRDA National Stock Hatch Rallycross Champions 2006 and MDA British Stock Hatch Rallycross Runners Up 2006.

 

Sure the driver is excellent, but the engine has made a big and highly visible impact on his season, and a win in stock hatch is something to be very proud of. You can see the car pulling away from others, and the result is even more impressive when this car is on grp N fixed platform suspension and the others are running coilovers.

 

Strangely enough the driver is having DES build the next engine too, advise on many other aspects of the car, and other competitors are banging on the doors in the scrabble to get the edge on the others.

 

So are DES just lucky when they throw these engines together, or does the care, attention and seemingly endless prep work pay off?

 

I have utmost of respect for Skip Brown Cars, have used them in the past, but to suggest that QEP and DES just put together engines is a pretty big insult.

[Robsbc 0 1 Cars]

I have utmost of respect for Skip Brown Cars, have used them in the past, but to suggest that QEP and DES just put together engines is a pretty big insult.

 

Well they do don't they just better than the average Joe mechanic? I did praise them if you read earlier...

[smckeown 1]

The rest of the 8v/turbo/16v bickering is just pointless.

 

It's not bikering. My agenda is to have a construtive discussion.

 

It's all relative to the weight of the vehicle. What we're talking about with the TU and XU is 15 or 20 kg in an 800kg tin top. It's only about 2% of the vehicle weight. Bugger all basically. It's the same weight as 5 gallons of petrol. Who thinks they can actually discern a speed or handling difference in their car when it has a full tank or a half full tank?

 

On my 750kgs car the iron block is 30kgs heavier, that's 4%. I believe you would feel the difference, that's whty I'm sticking with the XU9JA. As well as the regulations aspect and as well as just preferring this route. My choice.

 

And there is no weight than can be moved backwards on my car; well certainly nothing as easy as a battery.

 

And the quote about des/qep just bolting egines together; well that's just a lack of education

[Robsbc 0 1 Cars]

And the quote about des/qep just bolting egines together; well that's just a lack of education

 

You would say that Sean as DES is bolting your engine together Only kidding...

 

To make you happier Sean SBC do prefer the 8v to the 16v...

[boombang 2]

Well they do don't they just better than the average Joe mechanic? I did praise them if you read earlier...

I probably did read earlier but was only replying to your one post.

 

Speaking for DES I agree with you, (haven't spent any time at QEP, although people I trust rate their work so same applies) they are a world apart from your "average" spanner monkey.

 

Read the phrasing in your previous thread:

 

"All they have done" "Nothing that nobody else couldn't do now by ordering those bits"

 

Sounds like you ARE putting them with your average engine builders and even home mechanics.

 

Trust me though, that more work goes into the thought, reasoning, prep, measuring, calculating and machining for a DES engine than your average Joe would spend bolting it together.

[smckeown 1]

You would say that Sean as DES is bolting your engine together Only kidding...

 

To make you happier Sean SBC do prefer the 8v to the 16v...

 

Being the position to have had detailed discussions with DES, PR and QEP about engine builds over the years (less so with QEP compared to PR/DES), you have to appreciate the time and effort they all put into a build; it really has been an eye opener.

 

Yes DES are doing my current build (no secret in that), and boy the package has been well disucssed and thought through. It also helps i've been through this before so picked up a few things that are important to discuss and agree upfront has been useful (and expensive..haha).

[Robsbc 0 1 Cars]

Why didn't DES build the engine instead of being done by a third party i.e QEP? Not capable who knows?

 

And regarding education I know of QEP as they are down the road to me and I know the guy who build's the QEP engines for Mat...

 

Any insults none intended...