GBruce

Hi,

I have asked this question on here before but need to be sure on this because I will be having the car mapped soon,

Standard uk engine with all the supporting mods, what do you think will be best?

1.4 bar to redline?
1.4 bar to about 6500 then to 1.3?

I have read that the ideal boost for this turbo is about 1.65 in the midrange dropping to 1.45 at the top, should I really push it and try this or is it a recipie for disaster? What is the ideal boost to run?

If the engine did let go I would be planning a super strong rebuild so should I just go for the optimum setting and hope it lasts as long as possible? Would save on remapping costs.

Thanks in advance


George

AlanG

I had no problem running my std UK engine at 1.4 bar to 7000rpm.

stevebt

iTrader: (8)

mmmmmm 1.4bar

john banks

The key thing to running this turbo and keeping the engine in one piece is the exhaust manifold IMHO. The gains are considerable at this level and you don't need to run silly boost so it spares octane hunger and your engine I reckon.

stevebt

iTrader: (8)

which manifold do you recommend

EMS

I have seen lots of different manifolds on customers cars, the best allround performance against a good price gives the GT-Spec GenII manifold. You could have a tad more midrange torque with some of the true equal length manifolds, but always with some loss of top end. The GT-Spec GenII has a spool up only a bit worse compared to standard, with increased torque and top-end performance.

Mark.

GBruce

Hello,

I have the version 2 Gruppe-s manifold on with a 2" h+s up pipe (No leaks yet, touch wood)

On my last run on the dyno with the TD04 peak power was said to be at 6300 rpm, will this change with the bigger turbo on? If it doesn't, is there any point in having all that boost above this point.

If you are a mapper and was going to map my car (98UK) and everything was working correctly and there are no problems what boost would you map in?

550 injectors
FSE Pump/Reg
APS FMIC
TD05/06
Original SS exhaust inc up pipe, no cats
Gruppe-s headers

Anyone gone higher than 1.4 bar on standard engine internals with or without failure?
Is it better to run more throughout the midrange to give more torque?

Alan,

Seen your car in the recent issue of jap performance, looks good :-)
The write up says you run 1.5/1.6 bar is that engine standard?

Will the 550cc injectors be enough?

Thanks

George

AlanG

Hi George, yes the engine is std, no internal mods done at all, only bolt on bits.

I also had the Gruppe-S manifold and up-pipe on the car when i ran 1.4 bar. The up-pipe was a large bore non slip-jointed type (early manifold).

Peak power on my set up moved from approx 6400rpm to 6800rpm when the headers were fitted.

I used 740 injectors at this power level, not 100% sure about running 550's, though possible with a higher fuel pressure i believe. Perhaps other 05/06 users can clarify what's best.

John Banks ran higher boost pressure than 1.4 bar on his std 2.0 but this was with the std headers (albeit ported?). Putting the aftermarket headers on gave similar power but was better for the engine because you didn't need to run so much boost to achieve it.

Andy.F

As Alan has said, if you run std headers then you will need around 1.6 bar to make the same power as you would with 1.4 on headers.

I know you shouldn't compare different rolling roads but my 95 WRX on Std internals and Sti pistons made 432bhp at 1.65 bar at Well Lane on ported std headers.Then made 440bhp at 1.45 bar at Star Performance on Gruppe-S headers.

1.4-1.45 bar is the 'sweet spot' for this turbo on headers, any more boost and you can improve midrange torque but top end power can drop off due to backpressure build up in the exhaust.

Both runs were using Optimax plus octane booster on 550cc injectors and increased fuel pressure.

Andy

stevebt

iTrader: (8)

pleased im changing my exhaust to BLITZ then

AndrewC

I would have thought the biggest restriction would be the TD05 exhaust housing.

Andrew...

CustomScoobyIOM

But he is running a TD05/06 20g......

AndrewC

Exactly, big compressor small exhaust housing.

Andy.F

Yes it is the exhaust housing/turbine that limits output to circa 415 on Optimax or 440 with octane booster.

Andy

RRE

When you guys talk about standard internals, is it then always the STI engines or is it also the "normal" GT Turbo engines?

Thanks

Rasmus

john banks

Either.

RRE

How different are the 99 STI to the 99 GT internals? Is it only cylinder heads or is it also crank, pistons and rods?

john banks

Heads and pistons.

RRE

So the weak main bearings would be just the same issue on the STI as on the GT?

GBruce

Thanks for the help everyone,

Do you recommend holding the 1.4/1.45 boost right to about 6800 rpm then, this would be easier to map wouldn't it?

George

XNWRX

Yes, but wait for the remap before applying 1.45 up to the red-line ;-)

AlanG

I ran 1.4 bar to 7000rpm then tailed off after that.

Because the revs rose very quickly in gear, i set my rev limit to 7500rpm, this was because the Link ecu i had in at the time was bringing the limiter in to play before i had reached 7000rpm, but this was only in 2nd and 3rd. The Link seemed to sense the rate of acceleration (revs) and so stopped the engine from going bananas before it got to the set limit. IYSWIM.

The other problem i had was because the car accelerated really well in 2nd and 3rd, i tended to go in to the 7200-7300rpm bracket before changing gear ( I couldn't watch the road and the rev counter at the same time). In 4th and 5th, the revs didn't go up quite so quickly, so you had a bit more time on your hands to get a grip on what was going on and get a feel on when to change gear.
With the std headers you can feel the power tailing off after 6500rpm, so you instinctively change gear but with peak power at 6800rpm, you tend to change up that bit later. This is where i feel the 8000rpm limit of the Sti engines would be nicer.

Pavlo

The real question is:

Does your wallet have uprated internals?

Paul

GBruce

LOL, There seems to be a problem with my wallet, it has a big hole in the internals, It has been getting worse since I bought the car a couple of years ago!!!!