Race Engine Forum UK

Thought it eventually was time to post something about my car on this forum too.

The car is fully rebuilt and uprated in most ways, prepped for trackdays.

The reason why I'm posting is mainly because of the engine. I've been planning the engine for 4 years now, and finally it's actually assembled, and running fine in car :) (sometimes never though that day would come).

The fun thing about it is that I decided to increase the displacement volume as far as possible without spending too much money on a custom crankshaft.

Final spec of the engine is like this:
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Engineblock: XU10 cast iron with oil-squirters under pistons
Crankshaft: Forged item from 2.1 TD engine, increased stroke from std. by offsetgrining rod journals.
Bore: 88mm
Stroke: 94.5mm
Displacement: 2299cc
Rods: Custom Crower H-beam, BMW big ends, undersize bearings (47.5mm journal size)
Pistons: Forged Wiseco

Head: 1.9 Mi16, ported by local enginebuilder, oversize Pumaracing inlet valves (36.5mm)
Camshafts: Catcams, 286/274 degrees, 3.85/3.25mm lift @TDC, 12.45/11.80mm max lift (inlet/exhaust values)
Solid lifters, uprated single valve springs and uprated retainers.

Jenvey 45mm throllebodies with Longman/Jenvey inletmanifold
Exhaust, 309gti16 manifold, mated to home made 2.5" exhaust system

This is the first engine I've made and I'm very pleased with it, and so much fun it's building!

I had it mapped and dynotested wednesday this week, and it showed up 250bhp@wheels. I think the dyno must over-read a bit, but I recon a engine figure of 270bhp is what's most likely.

The car would wheelspin in 4'th gear with road tires, so it's a little handfull to drive it now!

Hilgert from 205gtidrivers forum made a video and put on Youtube.
It's some misinformation regarding engine specifications though, but you can see some pics of it and the rolling road session videotaped.
http://www.youtube.com/watch?v=XQKSrdmEzwc

Comments apreciated :)

I also wonder if the exhaustmanifold may be the reason for the very bumpy torque curve? I'm thinking it might be a little bit restrictive, although the engine seem to make very good power anyway.

What a cracking car. Always loved the 205 shape.
Engine looks nice and strong, but the exhaust manifold is robbing you of power and torque. It's bore is too big, and it is over complicated with too many bends which will slow the gas speed up. I would want a much straighter tract run. With the engine tilted back, does it make it harder or as i suspect easier to run a better design?
For your first attempt, you have done a brilliant job. Well done!!

Andy.

Thanks for comments :)

I really like these little cars too, this is my 3'rd one now.
And I also got another 1991 205 GTi 1.6 which I'm restoring to it original form.

I know the exhaustmanifold isn't very optimal for flow at all, but at least it's got equal length runners.

I might be able to get one of these for a reasonable price:


Just need to change the flange, but I think those tubes look even bigger.
The ones in my existing manifold is like 38mm inner diameter.

I guess it would be pretty easy to have a good straight design header, but the problem is fabrication as it's very tight of space so think it's hard to make one from scratch myself, I'm not that good at welding / fabricating yet.

More camshaft technical, anyone think I can adjust them a little to get the curve straighter, more constant VE?

Kristian, hi

congratulations on many things - superbly illustrated and technical post in outstanding English (well done!), stunning car (and background, with real Norway snow) and power results.

I don't know the cam timing, so I can't suggest alterations to help that torque curve yet. Many engines exhibit dips in the torque curve, it may not be possible to enhance it. Let me know the full lift timing please.

I have to say that the results are nonetheless very good.

GC

Hi Guy.

The standard camshaft figures from catcams is like this (all figures inlet | outlet) What I've done at the moment is to just measure the lift at TDC, and set it to 3.65mm on the inlets, and 3.25mm on the exhaust ones.

The thing is it still have rising powercurve at 7500rpm, and I'm not planning to run it any higher than like 7800rpms, so maybe I'm better of advancing the inlet to the stated 3.80mm lift at TDC?

I'm very pleased with the results myself too, a better ECU would help a lot I think as the AFR curve is now all over the place, due to big variations in VE over small variations in RPM.

Hopefully I'll get it registered for the road in about 1 months time, and be able to test it out a bit more seriously on the road.

OK< well done.

The LCA - lobe centreline (or separation) angle here is 108 + 108 = 216 deg. There is strong evidence that heavy overlapping ie: a closer LCA gives more area under the torque curve and flatter top-end bhp. Bigger engines can take closer LCA better than smaller ones and yours is a 2.3 liter..

I suggest you try Full lift posns 102 inlet and 104 ex. LCA 206 deg. In other words we open the inlet 6 crank deg earlier and delay the ex valve closure by 4 crank deg. This will have the effect of increasing the overlap. I may be wrong - but I think this may work. You will need to check your piston to valve clearances with a full dry build (two crank rotations), see GC V/W for how-to if you don't know.

The new header looks good - long primaries, short secondaries. All the software and dyno info I have says this is better than short py, long sy or equal lenght py-sy. Another overturn in contemporary thinking.

GC

Ok, thanks for input.

I think I acrually might get into trouble with valve-valve clearance at those settings, but as you say, dry test first, hopefully I can do it next year or something after the ECU is upgraded.

I've not bought the new header yet, but it's possible I can get my hands on one, the existing 4-1 one has 630mm primaries, but it doest look like it because all the pipes are so twisted :)

Also attached the AFR curve from the same pwoer run as the powercurve. You can see how it's all over the place.

The 4-2-1 header might well make a big difference to smoothing the torque and fuelling compared with 4-1!

GC