Thanks SteveW and johnfm. OK, so I guess we can say that we agree on almost everything so far. If I decide to go down that route I will post the results whatever they are.

I have read the puma racing link some time ago.

I think that is it for me on this thread.

 

[quote]Originally posted by Christer:
<strong>Thanks SteveW and johnfm. OK, so I guess we can say that we agree on almost everything so far. If I decide to go down that route I will post the results whatever they are.

I have read the puma racing link some time ago.

I think that is it for me on this thread.</strong><hr></blockquote>

I spoke to Jonas at JZ yesterday. He reckoned around 15BHP increase for cat bypass and chip. He did say it varies car to car between 10BHP and 20BHP. Frankly I trust the Guy. My Diablo driving friends reaction when I took him for ride after mods sums it up.... "what the **** have you done to this car"

BR
Piers
1990 C4 Coupe

 

Piers,

After skimming the threads once again, I didn't see any mention of your impressions after the mods were done. Aside from wanting to quantify the actual HP or ft-lb, how do you find the car behaving throughout the power spectrum before and after? Greater pull, stronger top-end, etc.?

 

Dear Mbster!?

The car was 24K mile serviced at same time, this was 4K mile after I bought it and it's the first fast Porsche I've owned (had a 356B Super90). So it's difficult to be completely sure what the mods achieved versus the service. Furthermore airbox was drilled at same time increasing noise under load which has, at least with me, a psychological effect i.e. more noise = faster!

Basically it just feels faster all the way through the gears, in particular at lower revs and, I think at top end revs. I've had to take more care to not hit rev limiter as it seems to happen faster.

At the end of the day I don't know which mod - chip or bypass - has caused how much of the total improvement. All I do know is that it is definately better/faster/noisier! Furthermore Having met and got to know the JZM team I honestly don't believe they are the sort of people who would rip me off £600 for no improvement.

Jonas at JZ reckoned improvement should be between around 15BHP max. PS Anyone thinking of Supercharging be very carefull - speak to him first.

BR
Piers
1990 C4 Coupe

 

they did all that work for 600 quid? 24K service, chip and bypass?!

 

Hi,

[quote] Basically it just feels faster all the way through the gears, in particular at lower revs <hr></blockquote>

I agree with the comment about feeling faster at lower revs. I had a cat bypass and a chip fitted at different times (chip was fitted second) and the main thing I noticed was a bit more low down power. There is no longer the kick at 4K rpm that there used to be. At higher revs I don't notice any difference - no faster or slower than it was in my opinion - but definitely a bit more drivable.

Dave
90 C4

 

But I like the kick at 4000 rpm!!!

BTW, anyone got a tip out there?? Notice how you can't quite redline in first - it changes up early, at about 6200 rpm - bummer!!

 

[quote]Originally posted by mbster:
<strong>they did all that work for 600 quid? 24K service, chip and bypass?!</strong><hr></blockquote>

I wish....No! £600 was chip and decat/bypass!

Piers

 

Did a search and found this interesting thread!

So what happenned? Were there dyno charts posted on another thread? Was the drivetrain loss on C4 ever resolved?

Cheers

 

Nope..... <img border="0" alt="[nono]" title="" src="graemlins/nono.gif" />