Trebor69

Hello All Currently running

93 WRX - Soon to have STI V9 BLOCK Inc Pistons/crank
HKS FMIC
HKS FCD
HKS Air Intake
VF34 Turbo
Z4 ECU with Uni-chip
3" Full system de-cat
Dawes at 1.1 bar

Going to be fitting a Electronic boost controller when car comes back from API and has been run in.

What I am looking for is a EBC that will allow me to alter boost level at certain rpms as i believe this is the best way to go.. say 1.4 bar till 6k and 1.2 or 1.1 to redline. I believe this will keep EGT's down and be much better for engine??

I know to go to 1.4 bar I will need to make sure fueling is correct. hence going to fit Fuel pressure reg at some time. What I will be doing at first is 1.1 till 6k then .9 or 1.0 till 7K for now..

I want a fairly user friendly unit and be able to run 2 or more boost levels (low and high).

I have been looking at the Apexi EBC controller (digital display) as this seems to be able to map boost to rpm and gear????

I know these retail for about 350 plus VAT.

Let me know what you think to above...

Now then...... Another angle... 400 quid for above unit.... For another say 600 quid.. I could go apexi ECU couldn't I ?? And could this control boost to rpm I.E 1.1bar til 6k .9 TO 7k? This would also allow me to run 440 or 550 injectors then, thus allowing me even better control over fueling than UNI-CHIP... Does the Apexi ECU allow different settings I.E low/higg boost levels like EBC's do?

Looking forward to your replies...

Cheers
Rob

john banks

1.4 bar at 6000 RPM is too much for your VF34, try 1.1-1.2 to be sympathetic, and 1.0 at the red line.

You don't necessarily need an EBC to taper boost, on the standard actuator the EGBP will drive open the wastegate anyway and give you a reasonable profile, although most VF34s don't have an adjustable wastegate linkage.

harvey

iTrader: (48)

For £700 or there abouts, Andy Forrest will fit and map a new Apexi Power F.C. ECU.
chances are that you would not need an EBC unless you specifically want to map the boost separately. BTW the AVC-R is available for around £300 delivered.

XNWRX

The best one for the best price I know is the Apex-i AVC-R.
But listen to what John said, the VF34 is too small for your conf.

Trebor69

Hello All

May probably go the ECU route, All depends on what boost I can run with current set.. If I can run 1.1 bar safely at mo with dawes... Wonder if it would be worth going further if I cant really run more boost with this turbo.. Could be a lot more money for very little gain...

John could you please advise me on what boost i can expect to run with my VF34 then. I don't really understand compressor maps. If you could say exactly what boost levels I could run up to say 5k and then 5k-7k etc etc

So what would happen if I tried to run 1.4 bar on this turbo, would break it, or ????

Cheers

Rob

john banks

I would suggest 1.4 bar at 4000 RPM dropping 0.1 bar every 1000 RPM after that... just as ballpark guidance from experience with this turbo. The compressor map is not public domain for a VF34.

If you run too much boost on what is quite a small turbo you increase charge temperature, retard ignition, raise exhaust manifold pressure and temperature and lose power and reliability.

1.4 bar at 6000 RPM is 380-400 BHP territory if everything was very efficient.... maxxed out 550s... quite a lot of air... trash a non-STi gearbox in weeks....

Trebor69

Hello John, Thanks for the informative reply.. funny when i puchased this turbo as much deliberation, the supplier told me it was a mid to high size turbo hey ho.

Think my best bet then would be just to get a EBC that can map boost better than my dawes. will run at 1.0 bar and get unichip re-mapped after running period. on dawes when running at 1.0 bar it slightly peaks at 1.05 -1.1 bar in 4th and 5th. This was giving me 290BHP 275LB torque at PS Rollers. I am getting headers and up-pipe ported by API whilst doing my engine, hope fully give me a bit more lower down torque and better spool up.

Think I may just keep power as is.. tis very quick allready afterall ... and spend money on a set of 4 shocks, allready have 4 pots and vented/grooved disks. get a better overall package then....

cheers
Rob

john banks

Don't worry about a small overboost in high gears if the fuelling and timing are OK.

Trebor69

When mapped with unichip at P.S when peaking 1.1 bar everthing was running fine, I even had it at 1.1 bar peaking at 1.15 towards redline and was fine then.

I used to have a UK 7D ecu without uni-chip which i reckon was fitted for its uk map for Uk fuel. I since fitted a Z4 ecu which i was advised had better base maps albiet for 100ron fuel and fitted a unichip to enable fine tuning to suit it more to optimax.. what do you reckon to this? Once I get car back from API, I may run it on optimax and octane booster.. Is it ok to use octane booster with optimax with just standard ECU in.. I will refit unitchip and get it mapped once ran in using both.

Seems to go for another 50-70 horses , means ECU, Injectors, fuel pressure reg... On the road I don't think it makes that major a diffo and considering i may break my gearbox etc... seems no too good an idea... Ill have to stop my brain going more power . better handling and braking instead !!!

cheers again
Rob

john banks

Cue the ScoobyECU guys who have experience with these ECUs...

Trebor69

P.S John, I am running a HKS FMIC would this make any diffo to what boost i could run??????????

Rob