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WRX Cutting boost after 5500?

3K views 17 replies 6 participants last post by  Kutarkvalidus 
#1 ·
A friend of mine who owned an 02 WRX told me that his ECU would cut boost shortly after 5500 RPM. I haven't read anything on this yet so far everything i have read just indicated the stock turbo wasn't capable of maintaining full boost to redline. Has anyone encountered this problem? Was this an 02 only thing, or was my buddy dreaming some **** up ;-)>.

Either way, if it is a common problem is there any way to combat it? I.e. electronic boost control etc?.
 
#3 ·
Hrmm, yeah thats what i had been reading. So my question now is should i buy say a garret hybrid with about the same output that can handle the boost to readline? Would i be able to slap it on or would it need tuning?

A DSMer friend of mine mentioned something about the Fuel Maps on the stock ecu would **** it over since it would be boosting sooner and harder than the stock and the ECU wouldnt provide enough fuel or the right ratio etc? something along those lines. Any truth to that statement?
 
#4 ·
Get a Cobb access port, Walbro Fuel pump, and bigger injectors along with a VF Series, and COBB has maps for that setup for the 02-03 One of the larger VF series turbos will make boost at higher RPMs, but might lag a little town low.
 
#5 ·
ALT+F4 said:
Get a Cobb access port, Walbro Fuel pump, and bigger injectors along with a VF Series, and COBB has maps for that setup for the 02-03 One of the larger VF series turbos will make boost at higher RPMs, but might lag a little town low.
This is what I have done with my '02. 17+ psi all the way to redline! :)
 
#7 ·
Kutarkvalidus said:
Hrmm, yeah thats what i had been reading. So my question now is should i buy say a garret hybrid with about the same output that can handle the boost to readline? Would i be able to slap it on or would it need tuning?

A DSMer friend of mine mentioned something about the Fuel Maps on the stock ecu would **** it over since it would be boosting sooner and harder than the stock and the ECU wouldnt provide enough fuel or the right ratio etc? something along those lines. Any truth to that statement?
that large of turbo is really not necesarry, and make create some reliability issues down the road and need extensive tuning.

your best bet would be,( Access Port ECU from cobb tuning, catless turboback + uppipe, upgraded fuel pump - walbro is good, bigger injectors, and a VF series turbo) -- the vf22 will give very good top end, but will give huge lag. A good median turbo to create more top end, but not create a crap load of lag would be the vf30 or vf34. <<<< this all tend can be had for about 3 grand if you shop well.



 
#8 ·
Kutarkvalidus said:
A DSMer friend of mine mentioned something about the Fuel Maps on the stock ecu would **** it over since it would be boosting sooner and harder than the stock and the ECU wouldnt provide enough fuel or the right ratio etc? something along those lines. Any truth to that statement?
You can run a larger turbo with the stock injectors, but you'll have to turn the boost down (with an MBC) so low that it isn't a worthwhile venture. To make it do its thing, you really need larger injectors, which means you'll need engine management. (stock ECU can't deal with any injectors except the stock ones) I used AccessPort; UTEC and Ecutek are also good solutions, and are also currently tunable by personnel other than the manufacturer.
 
#9 ·
My main concern with going with a fuel pump, injectors, new intercooler and a turbo isnt really cost so much as reliability and safety. This will me my only mode of transportation for the next 4 years at least. SO the last thing i need to happen is a blown engine due to poor tuning etc.

I was reading online last night about pre-programmed ecu's from ecutek etc. Though they mentioned they could only be prog'd by the company.

Regardless, downpipe/uppipe and catback exhaust will be the first purchases i make after the wheels/tires.
 
#10 ·
If your main priority for your car is reliability, then don't mod it.

If you do decide to get the downpipe/uppipe & catback, then you should consider getting engine management to go with it. Otherwise, you're not optimized for your hardware, and are leaving a lot of horsepower on the table.
 
#11 ·
Well you can still have a modded and reliable car as long as you don't go too ape****. I just don't want to end up having it tuned or tuning it myself and overlook some detail. I'm really just being paranoid i guess.

How much can you expect to gain with the exhaust setup etc without tuning as compared to tuning.
 
#12 ·
I just hopped by cobb tuning's website. Very professional. I just don't know a whole lot about tuning. for example the preprogrammed maps they have, does altitude have an effect on that?

If i can buy a VF34, injectors, and leave stock intercooler in place alongside the exhaust mods. And pull 300 ish HP out of that engine i would be very pleased.
 
#13 ·
Any change that you make to increase the output of your car will have an adverse effect on it's longevity. The EJ20 is a stout enough engine design to take simple mods well, but don't fool yourself into thinking that there's no tradeoff.

Having said that, there are already people on this forum with over 100K on the odometer, and with mods. Take care of your modded Subie, and it should take care of you.

Not sure how to respond to your last question. There's engine management, and then there's "tuning". Most people I know of that are running a Stage 2 level of mods (up/dp,catback) are running engine management in the form of either UTEC or Cobb, and are running base maps. In other words, off-the-shelf. Their car hasn't been "tuned", in the sense that people use the word.

I don't have a number for you, but I know that there was a pronounced difference in the acceleration of my car when I went from Cobb Stage 1 w/ downpipe and catback to Cobb Stage 2.
 
#14 · (Edited)
Ok, well i've always been told tuning was essentially where you either had an SAFC or some sort of EMS. In which you programmed you fuel maps etc. Or a shop would do it etc. The whole download a preprogrammed map thing is new to me, and very cool i very much like the idea of it.

As for the reliability longetivity thing, i am definitely not fooling myself, i just simply wish to have an engine last longer than say 70k miles etc. Obviously a mod will wear the engine out faster, just like higher boost etc. but its the amount that is important to me heh.

As for the stage 1 stage 2 etc. What precisely does all of that mean or entail?

Edit: Forgot to mention on the altitude thing. Everyone i've talked to has said that the fact that we're at 6000 feet in elevation it screws us three ways from sunday when it comes to getting the most out of a certain type of mod.
 
#15 ·
The stage thing really depends on the manufacturer. Cobb has their stages (1 is engine management, 2 is EM plus turboback exhaust and uppipe, then they have reflashes for a couple of different turbos.) Many people here use TurboXS's system:

1-UTEC engine management
2-UTEC plus turboback
3-Stage 2 plus intercooler
4-UTEC plus turboback plus uppipe plus injectors plus pump plus upgraded turbo.
 
#16 ·
I like the fact that cobb has a map for stock intercooler etc on a VF34 with injectors. I was looking heavily at a VF34 earlier on, but didnt know what options i really had to get the car with a good fuel map. DSM friend of mine suggested an SAFCII but i just dont like the whole piggyback operation, not to mention the WRX ECU apparently can learn around it.
 
#17 ·
Kutarkvalidus said:
I like the fact that cobb has a map for stock intercooler etc on a VF34 with injectors.
Yeah, I like that too. I'm married with kids, and I didn't have the extra grand laying around to buy another intercooler!
 
#18 ·
Well that really nails down the decision on turbo upgrades etc. My only thing, and ill probably have to email cobb, is the altitude, im not sure what they tune those maps for. So ill just make sure it will work for my situation.
 
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