yhe chod

hi, i have a uk99 car [30,000 miles] and have recently done the following modifications;

standard turbo [td04]
new maf and lambda sensor fitted
ported and heat wrapped exhaust manifold and up pipe
3" heat wrapped roger clarke downpipe [no cat]
3" revolutions centre and back box [no cat]
sti panel filter [sucking in air directly from inner wing]
tek3 remap of original ecu by bob rawle

my problem is that i am not 100% happy with the way the car is performing compared to when i had the prodrive performance package prior to the above mods.
specifically it feels less responsive and not that much better than the ppp in terms of power and torque.

what i want is the drivability i had with the ppp but more torque and more instant responce from the engine. better pick up from the traffic lights and in gear pick up [especialy 3rd gear].

i suppose torque at lower revs, and quicker responce from the engine without getting bogged down is what im ultimatly after .

so can anyone reccommend any suggestions or modifications to reach my goal
or indeed reccommend a company i can take my car to to diagnose any problems with the car.
thanks in advance.

FB Tuning

iTrader: (30)

Stick a TD05 in it, and get the map altered
BTW, how much boost have you had it mapped for?

yhe chod

max boost is 18psi [1.2 bar]

wouldnt the tdo5 increase lag hence lose the responce/torque im after?

what about the vf35 or vf34 instead of the td05 turbo?

AvalancheS8

The 3" exhaust will be hurting your spool up and response with the standard TD04 turbo. It might be making a little more power at the very top end but it'll be making less at lower revs. There's no need to go with a 3" exhaust until you are well over 300 bhp. Changing to a TD05 turbo would make the lag at the bottom end worse, but it would make far better use of the 3" exhaust. IMHO the car would feel better and punchier on the TD04 with a 2.5" exhaust system. The 3" will probably get slightly better figures on a rolling road, but in real use, it'd feel faster with the 2.5".

For torque and instant response, other than going backward on the exhaust size, you could probably help things with a well set up aftermarket boost controller, the Apexi AVCR is supposed to be good in this respect.

yhe chod

what is the purpose of the boost controler?
does it mean i can program it give big boost at certian revs ?

AvalancheS8

The main reason a good boost controller can help spool up is that it can keep the waste gate completely shut until just before target boost, so the turbo spools faster. With the normal boost control the waste gate actuator is always seeing some pressure and just below the target boost pressure it may be starting to open slightly which makes it harder for the boost to build up. By keeping the pressure away from the wastgate actuator entirely the aftermarket boost controllers can get the turbo up to the target boost faster.

It would also allow you to run higher boost in the mid range but that is something to look into carefully before you just whack the boost up a bit.

Jay m A

iTrader: (2)

Sorry but I don't buy into lower back pressure post turbo increasing lag.

The turbo itself is the main restriction, and I agree that speed of exhaust gas pre turbo is relevent to spool, but post turbo I'd want as little back pressure as poss.

Just my opinion