James_Harvey

Folks,

Just wondered if there were any answers to the below?
I now have the STi nearly run in, so will be swapping bits very soon

James.

MurrayZA

I and getting overboost in my PPP 01 WRX with VF23 with a replacement cat-free exhaust. Its not really a spike - but more held. It now holds at 1.3 bar - where it was previously 1.1
Any ideas if the restrictor will fix this. It spools very
quickly and gave 1.1 bar in 2nd.... !!! Anyway, the car is
now parked until I can get a fix. Since its a daily driver,
this is most inconvenient. Would a 1.25mm restrictor
work ? What is the std restrictor size in a PPP.

HELP. Please.

mutant_matt

Murray,

What's the peak and held Boost in 4th and 5th gear? These are the ones where you should see the most boost. You should change the restrictors to get the required boost in 4th and 5th, you should get a little less in 1st-3rd....

Matt

P.S. don't know the standard size/PPP size of restrictor, sorry.

MurrayZA

Hmmm.... I had WOT and 1.3 bar @ 6000 and decided that this was
a good time to stop pressing the loud pedal. This is not really
a spike - but held boost - it felt like 1.5 bar was on the cards...
Thats in 4th or 5th. I got 1.1 bar in 2nd. I have no Dawes, EBC, MBC or the like. Just a PPP with full decat and a VF23 thrown in for luck 8-) - seriously though.

STD PPP WRX 01
Full exhaust up-pipe to back box (PPP back box)
VF23/24 - not sure which (neither does the supplier I bought
it from second hand know - a refurbed Graham Goode issue - all
the way over here in sunny South Africa)

I think (THINK) maybe I recall that the PPP restrictor is 1.1 mm

LitchfieldImports

Super
Your welcome to take it for a spin Russell

Iain

[Edited by iainlit - 4/8/2002 2:43:02 PM]

mutant_matt

OK. I've now done some logging with Jonno (JDM STi) with his full de-cat with different restrictor (running Optimax + NF) and can compare the results to a completely standard UK STi:

Standard UK STi




JDM STi - Full De-cat with restrictor




As I understand it, Jonno is pretty much now running 1.05bar in 1st, 2nd and 3rd and about 1.2 in 4th, 5th and 6th. You can see that the spiking has gone (at the possible expense of some increased spool up time) but he still gets the occasional spike to 1.4ish (IIRC).

Presumably, with a 3rd party Boost controller, you could have the best of both worlds (fast as poss spool up but without spiking) and hopefully, EcuTek will also be able to modify the Boost maps soon, possibly coupled with a restrictor, to get this best of both worlds too.

Matt

[Edited by mutant_matt - 8/19/2002 8:24:15 AM]

mutant_matt

P.S. Anybody out there with a "standard" JDM STi 7 in the South East that is willing to have their car logged to see how that compares with Jonno's car?

Matt

Claudius

That's strange that your car holds more boost under higher load.

What do you guys think about that set up?

Razor2001

Nice work guys !

Is Jonno's car full turbo back + uppipe change or just full turbo back ?

What size restrictor is he running with the above deacatt system ?

What was the est. outside temp during the run ?

Cheers,
Ray

Pete Croney

Jonno is using an up pipe and full decat back, Ray. He is using a 1.3mm restrictor.

Razor2001

Thanks Pete.

I am still waiting to get my boost gauge. I really can't wait to find out what boost I am running. I am pretty confident that my held boost in 1st - 3rd gear is less than 0.6 bar. Almost got beat by a civic with a loud and squeaky exhaust the other day....no other mods Nada good...

Cheers,
Ray
STI-7 JDM, Full SS turbo back exhaust, 1.25mm restrictor size

john banks

I don't like that -ve knock correction in 6th gear on the UK one. Is that how they all run??

mutant_matt

Claudius,

Seems to be the norm for Impreza's.

Razor,

The temp was about 15degC (roughly)

John,

I've looked at 3 other UK traces I have (one from the same car) and it looks like a one off. I will get round to doing some tracing on mine soon so we'll see if mine does it. I am also going to do some more runs on the two UK STi's so it will be interesting to see if that car does it again.

Matt

Razor2001

Cheers Matt

alfriedesq

I have the perfect soultion to the boost spike problem

I have the sti JDM 2001 new age motor and trans

I fitted a giant Garret GT 30 t3/t4 turbo with tial external wastegate and custom fm sperco intercooler

Now boost spike is a NON issue

I get 22 psi in 1st gear with ease and at least 400 hp to the wheels I am willing to email someone my delta dash logs if someone wants to post them here - I can figure out how to do it

alfriedesq

Sorry ment I can't figure out how to post the data logs

mutant_matt

Mail them to me and I'll put them up....

Matt

Paul N P

Matt,

My STI UK traces are on the Ecutek website, at the time I was running with full PE system from turbo back. Car goes like stink!

Do you think an up-pipe would make much noticable difference to the STI UK?

Paul

mutant_matt

Paul,

Those that have fitted an U/P have said that it improves the spool up time and throttle response but does make the Boost spiking worse. If you did it, you'd probably need to change the restrictor again (do you know what size they used last time?)

Nobody out there with an un-modded JDM STi 7?

Matt

Razor2001

bttt

Paul N P

Matt,

No idea what restrictor was fitted, all done by Mervyn at PE on the rolling road with Steve Done in attendance with Delta-dash running, certainly no issues with over boost now though.

If I go for the up-pipe I'll get PE to do the same again on the rolling road.

Anyone got any idea how long it takes to fit up-pipe? I've heard its a fairly labour intensive job.

Cheers

Paul

Deep Singh

Alfred,yours is hardly a simple solution nor makes complete sense.Firstly it would cost thousands of pounds.Secondly,have you had the ECU changed/remapped if not how does the car cope with the new turbo and fmic.I cannot beleive that you have acheived 400 BHP on the standard ECU.
Matt,the uppipe did not cause me too much problem.I went from turbo back system (with 1.25mm restrictor) then added the upipe a few months later.Max boost in higher gears went from 1.1bar to 1.15 bar.No det.I'm going to actually going to change down to a 1.2mm one and risk running 1.25-1.3 bar.

Deep Singh

Alfred,according to your post you are running close to 1.6bar boost in 1st gear!!

Paul N P

Deep Singh,

Did you notice much difference once you fitted up-pipe? I'm seriously thinking of getting it done, definitely worth the effort or not?

Would really like to hear your views.

Paul

alfriedesq

Yes 1.6 bar boost in 1st gear

yes - it did take many hours to complete the install - at least 60

Not to mention at least $1,000.00 in stainless pipes and fittings

The stock ecu actually held out fine to 23 psi and 380 hp with a standard bearing T3/T4 turbo in the stock location

I was using the super AFC b y apexi with great results

After I moved the turbo intake to shoot to the side at the fender with a 3" intake tube - and added the giant GT 30 Garret Balsistic concepts 60 a.r turbo - then the MAF sensor when crazy and I could not get it to idel right and the decel was way messed up

I re-installed the stock air box and it ran OK - but I could not close the hood

Rather than spend tons of time trying to get some intake tube to work with the monster turbo - I deceided to change engine management

Now I am in the process of fitting a LINK plug in which will enable me to hopefully go fully MAP based tuning and also run some 650 injectors I am dying to try

I got the new turbo from www.forcedperformance.com - - its an amazing custom unit they whipped up and I never felt that much boost in 1st gear before - - I was lucky to make 17 psi in 1st with the stock vf30 set up

I don't think that it would be that difficlut to weld in a TIAL 40 mm external wastegate on a aftermarket IHI stock style upipe tube - - that would eliminate all boost spike issues 100%

mutant_matt

AlfriedEsq DeltaDash trace:



The peak Boost on this graph is 1.47bar/21.4psi. Here is a close up of the Boost:



The Boost being pulled back at 5600rpm is interesting. Alf, it would be interesting if you could try doing a run with Engine Speed, Ignition Timing, Rear O2 Sensor, Air Flow Sensor Voltage, Knock Correction, Manifold Relative Pressue and Primary Wastegate Duty Cycle so that we could see what is going on and so that it is more comparible with the other traces we have?

Where was this run done? On a Dyno or on the road? What was the ambient temp?

Cheers,

Matt

[Edited by mutant_matt - 8/21/2002 8:14:31 AM]

Pete Croney

If that turbo isn't fully spooled until 4600rpm, then there is no way on earth that it is giving 1.6 bar in first gear. Let alone with a front mount fitted.

Deep Singh

Alfred,some very interesting things there matey.You've gone a different route to most but if it works...
Paul,yes there is a difference but d'ont expect it to blow you away.I'm getting everything ready for fmic and ECU so it makes sense for me.You will feel it though...

ustolemyname??stevieturbo

iTrader: (1)

Am I right in saying that it says on those logs, injector duty cylce is going to 140%
That doesnt make sense, but then, neither does 400hp at the wheels....maybe hes been watching too much My Little Pony, as he doesnt say he has changed the std injectors either anywhere.

raybotha

Forgot about this thread , just to let you help people know I used this info to design my own restrictor size and am happy with outcome . Am using racing fuel exclusively now so just wanted to smooth boost out . I found the ECU couldn't cope with part throttle between 3500 and 4000rpm as it would go from .5 bar to 1.3bar , then back below .5 before settling on .5 bar . I only upped my restrictor from standard .9mm to 1mm and now the boost only creeps from .5 > .7 momentarily then > .5 stable , which is charictaristic of standard boost . Feels good , goes fast . Still can't believe how much difference a pipe makes .
Just for your interest I used a 1.2mm restrictor and also saw a slow boost build-up and higher boost held at high revs in high gears ie .9bar at 6500rpm in 5th, but car felt like **** . just goes to show how that overboost helps acceleration .
Ray