Supercharged 205 track car *Rear Coilovers and 16x8" revolutions fitted*

[xsi16v]

Went to dynodaze rolling road day yesterday. Wanted to see what the recent changes have made to the power.

Because it makes max power at the limiter i can adjust the power to what i want. The car made well over 340bhp when mapped but i only ever quoted figures of what the car made with the lowered limit (306bhp@7000rpm) Now i have sorted the inlet temps issue i was happy to raise the limiter back upto 8000rpm for the rolling road day.

Since it was last on the rollers for mapping i have made 3 changes

1) smaller exhaust system 2.5" insted of 3"
2) Bigger air filter pipe on the inlet of the charger
3) Raise the limiter

I was expecting 330-340bhp so was a bit shocked when this happened


374bhp so with the current weight thats 458bhp per ton

[scottie_436]

Awesome matt

[jpsaxo]

What a beast!!!

[xsi16v]

cheers lads. Got some vids of your car josh, want me to upload onto fb or your project thread?

[harry289]

Nice flame too

[dannygti]

So you've fitted a smaller exhaust??

[xsi16v]

Yes, first 1 was a overkill at 3". Been told by a few race exhaust builders that 2.5 is plenty big enough for 400 when no turbo is involved

I still have 3" off the manifold and about 600-800mm of downpipe

[dannygti]

Yea id say anymore power you'll be wanting 3" through.. Otherwise you will start reatricting it which will make it much louder. What sort of silencer/backbox arrangement have you got? Is it still too loud?

[mk1vts1]

that is just a demon! love it!!!

[xsi16v]

Originally Posted by dannygti

Yea id say anymore power you'll be wanting 3" through.. Otherwise you will start reatricting it which will make it much louder. What sort of silencer/backbox arrangement have you got? Is it still too loud?

There will never be anymore, im actually dropping the limiter back down to a sensible 7250rpm. No point in having all that power and popping a rod through the block after a few laps. Dont forget this is a standard engine running standard compression I think my mapper was spot on though, forged engine would see 450bhp easily. Food for thought haha.

As for exhasust size, i was told the opposite. Smaller bore will be quieter, seems to make sence to me. Unless its far too small and causing massive restriction like you said??.

Using the same size boxes (as big as i can fit) it actually dropped the noise by 11 db static. Theres obviously more packing on a box with a 2.5" bore than a 3" so that will help!.

Anyway, i was fine at cadwell but its 105db there and they dont really enforce it. A lot of people commented on how loud it was so i have (REVISION 3) exhaust being delivered tomorrow. Had enough of f*cking about with straight through boxes so im going for a chambered design.

[dannygti]

Originally Posted by xsi16v

There will never be anymore, im actually dropping the limiter back down to a sensible 7250rpm. No point in having all that power and popping a rod through the block after a few laps. Dont forget this is a standard engine running standard compression I think my mapper was spot on though, forged engine would see 450bhp easily. Food for thought haha.

As for exhasust size, i was told the opposite. Smaller bore will be quieter, seems to make sence to me. Unless its far too small and causing massive restriction like you said??.

Using the same size boxes (as big as i can fit) it actually dropped the noise by 11 db static. Theres obviously more packing on a box with a 2.5" bore than a 3" so that will help!.

Anyway, i was fine at cadwell but its 105db there and they dont really enforce it. A lot of people commented on how loud it was so i have (REVISION 3) exhaust being delivered tomorrow. Had enough of f*cking about with straight through boxes so im going for a chambered design.

Are the engines expensive? If not just buy a block and build it up over time..can never have too much power and I told you a way to make it more drivable even though you have more power..


Restriction is bad, the energy that would of been used to expell the gasses is now being turned into heat and sound energy.. That's only if there's a restriction like you say..

I'm making me a new exhaust soon, that will also be a challenge to keep quiet but I have a plan

[xsi16v]

not really expensive, ill pick one up if its going cheap!.

Tbh, im fed up with exhausts now. Dont know how other people dont have the same problem on s/c cars. Its different with turbo's as they drop the noise by a fair amount.
Thats why im just going to bite the bullet and fit a chambered box, if it losses a few ponies i dont care, its almost certain to work and at least its not going to cause me any more issues at trackdays.

[dannygti]

If you have plenty of space under the boot floor then it's easy, just fit a twin loop backbox but the biggest you can fit in.. Or get a custom made box done similar to what you'd find on m3's, porsche's

[xsi16v]

thats REV 3

[jpsaxo]

Originally Posted by xsi16v

cheers lads. Got some vids of your car josh, want me to upload onto fb or your project thread?

Can you send them to me on iMessage mate? It's free so won't cost you anything

[Proffitt]

Amazing build

[xsi16v]

While i have 5 mins i thought i'd update the thread.

Towards the end of last year i finally mananged to build an exhaust that keeps the noise under 98db. I had no choice other than to fit a chambered style box. It has added some extra weight but needs must!!. Unfortunately on the same day i tested the exhaust i stripped the teeth off 3rd in my gearbox at Donnington


Exhaust



Gearbox damage




After replacing the gearbox i booked another day at Donnington just before xmas. After about 5 hot laps........

Ohhh Dear








I knew this would happen sooner or later asking so much of a standard engine!. I was very suprised to see the piston has actually come off the rod, i was expecting the usual snapped rod or rod bolt.

A new forged engine is in the process of being spec'd, there isn't much on the market for these engines so it will all be custom 1 off parts. I wont go into spec untill its built but im expecting well into the 400 bhp mark.


While i wait for the engine i have a few alterations to do on the car so i can put the extra power on the tarmac. Ill be looking at changing spring rates, fitting adjustable lower arms and rear turrets.

New wheels aswell....

16x8 Revolutions (225/45/16 tyres) and wide arch kit






Should provide the extra grip required

[Chr15]

It was overdue forged internals anyway

Loving it!

[crisppug]

That engine did well diddent it realy. Was great to see you at donnington them few times matt,jee those mods sure will make it even more of an animal �� hopefully see you soon bud. Lets hope between us we have some reliable track days.

[AlexBp]

matt

those rims

this makes me want to get my 205 started even more now
only had it 3 years haha....