Thread: SR20VE+T low on power, please help!

I call Bullshit on Bullshit !!!!! I also ran over 500WHP on 72lb/hr injectors @ 3bar on a 54C ... I been boosting SR20's for about 16 years now.... Also I think VE's require more fuel then a DE as well.. On high overlap motors you also blow some of the fuel out the exhaust as well so something to consider as well..

Thats actually very reasonable .. What cams? and what boost I am curious .. Thanks for the info

stock cams, gtir manifold boost was 8-10psi. I would have to dig on the old forum to find out exactly what the boost was.

meaning my tune must be shit? granted thats a possibility.. but @JKTUNING has seen my tune an many many many logs and helped me out here an there.. i would think if something were wrong he'd have said something or corrected it for me..

i havent been on a real dyno, but i've used virtual dyno alot and on 8psi it says im making 260~ hp depending on the weather and road. my n60 maf is hitting about .4.86-4.90 volts and as i said the duty cycle %77-%82 depending on weather.. colder weather seems to eat more fuel.

current setup is:

2871r
tubular manifold
520 sti inj
n60 maf
3" TURBO back exhaust
jgs 40mm wastegate
stock sr20ve

granted i try to keep my timing pretty low, mostly because i havent had a chance to have the car on a real dyno to actually tune the timing map.

i have id1000's and a n62 maf on the way, that way i can turn the boost up an see what happens

duty cycle is relative to your A/F ratio and fuel pressure.

Stock fpr an afr is 12.0-11.5

I saw someone flow bench STIs and they only moved 503cc ... Also if you can IMO go with a MAP Sensor.. It too is a 5v sensor like a MAF and you just invert part of your table and it should work fine.. I have built a few stand alone units for the SoCal guys and we are running MAP sensor and they run WAY harder Martin picked up 3 sec a lap at Streets of Willow with no other changes and about same weather as well .. Also no need to buy costly MAF sensors .. Food for thought !!

fair enough on the injector thing, i've seen people flow them anywhere from 500 to 525cc.

i run nismotronic, the car already has a map and iat sensor installed, i actually ran on speed density for several months but the gas mileage was terrible and weather was really effecting my afr's i was constantly changing things.. this was prob due to me being a newbie tuner, i'm quite familiar with maf tunes however an have no problems tuning with them..

not to mention 40 bucks for a n62 is a great deal.

I could see that... Maybe MAP is less than optimal without a system that can do target AFR in real time and long-term trim control.. I don't think Nismotronic does that like the systems I build but I could be wrong. And please correct me if I'm wrong... Also MAF is usually more forgiving but from my experience a MAP yields more power.. On OEM hardware I guess I change my mind and would probably recommend using the airflow meter.... Best of luck to all .. Especially this guy with his lack of power..

Another thing that just occurred to me is have you checked all your electrical grounds.. I have seen sensor variance in voltage due to bad electrical system and it can drastically change the tune..


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To the OP

I seriously doubt it is the 2.5 dump. 3 reasons:

1. Power comes back at 170kph. This indicates a restriction in the exhaust is not the issue
2. your 2.5 dump with external gate will flow the same as a typical 3 inch with internal gate
3. You car seems to take a lot of timing and boost without detonation. If the exhaust was really such a big restriction it would detonate with the extra boost and timing from too much back pressure.


I think its a timing issue/VVL switching issue. Have you checked to see if your cams have skipped a tooth? Also I think you are switching your cams WAY too late for a turbo! Try switching the ex at 3.5 and the intake at 4. It really could be a case of that little turbo you have on there makes peak power around 5k, and you are on the low cams where the turbo breathes the best. Also explains the rise at 170kph....as I assume that climb is after the cams switch.

According to that graph you want to be switching the cams around 140-145kph, I think that's why it dips there and then climbs back later after you switch the cams. Not sure what the dip at 120 is though. Maybe that's when you need to switch, as the power was rocketing before that....


Hmmmm thinking about this further, I am not sure of your final drive ratio or the tire size, but I would guess the dyno was done in 4th gear (so 1:1), something around a 26 inch tire and 4.11 final drive. That puts your rpm at around 4000....

I really think you need to play with cam switch points and then get your tune sorted after. There is a LOT left in it!

Turbo switching points and NA switching points will not be the same. Your switching points might be alright for a gt42....but not the small turbo you have.