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

On his graph at 120kph what is happening there? Is the Vvl kicking in, if so disconnect the Vvl and go for a butt seat Dyno test. If it feels like it pulls better up to around 6700 Rpms, then it will help with diagnosing
Does your exhaust have any silencers/resonators and or catalytic?

timing is kinda high, pull a little up top, and she's a little lean unless he's running e85.
and he has a 3 inch after his down pipe, the exhaust gas has already started to cool by then so its not a big deal...his dp is 2.5

where the power starts to peak at 120km/h(no rpm on graph) is that your cam change over?? if so drop it down a little to smooth that dip out. add some fuel down low(444cc are most likely too small) or turn up to 4bar and try again. i can think of a few things that are most likely wrong

I was able to make about 340whp on 444cc at 3bar.. With VVL and turbo you need to ensure you have as little back pressure in the exhaust manifold as posable .. If you have 12psi boost and 25psi in your exhaust manifold from too small of a turbo and or small WG and bad flowing manifold your in trouble.. During overlap and VVLs have a lot the pressure will try to equalize though the engine and it will make no power.. Not saying this is your problem but it's the #1 way to not make power on a VVL .. If posable put a pressure gauge in the exhaust manifold and check BP to boost ratio .. Food for thought ..


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Man we've had this discussion a lot lately and some have produced dyno charts that showed a 3" cat-back exhaust (mandrel bent) made HP *everywhere* - on a *stock* SR20DE! Not even a VE. A DE with nothing else. No losses down low either although that still has some debate.

Edit: ok just read another post saying he does have a 3" exhaust. so I'm confused ha.

Agreed .. Nothing is to big for turbo... I have noticed as well 2.5 in intakes are too small as well even on a DE.. Martins car I built an ECU for and on the MAP sensor still pulled some vacuum with no MAF on a 2.5 intake.. Raul's VVL I tuned on MAP had 3.5in intake and Q45 TB no vac problem...


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Yeah I noticed that too but didn't say anything, why the hell does it have the "road speed" at the bottom of the graph instead of the RPM? Dynojet's tell you that anyway. For example I made my peak power, 210WHP in 4th gear @ 7980~ish RPM at 110MPH. That's with the big JMR header w/ 3 dump, 3" exhaust, no cat, N1 cams, valve springs, warm air intake, and a mild port and polish. N60 MAF w/ MSD window box activating VVL @ 5100RPM. Where is yours set at? 211WHP on 11PSI is insanely low, what were your torque numbers, and where is your VVL crossover set at?

I don't understand why there's no RPM bar on your dyno sheet, OP.

Yep, it actually appears that almost nothing is too big for the VE in general, boosted or not. Right now I have a 3" cold air intake on but I'm interested to see what a 3.25 or 3.5" would do on the dyno again. Maybe I'll get around to it this spring.

I'll sell my b14 in a full face palm of having no idea wtf is going on anymore if going from 2.5" to 3" downpipe frees up more than 40whp. That's just craziness and makes no sense..stop talking about his exhaust!!

-G

No no, no one is implying that. We are saying that's part of it. Thought if he went up to a 3 maybe he would have run a 222 instead. who knows

Thanks heaps for all the input guys
Okay, so. Like a number of people are saying, I highly doubt the 2.5" dump is holding me back from 50hp. The turbine outlet itself is only 2.5" and the dump is maybe 12" long before it goes to 3" the rest of the way.
Yes I do have a hot dog muffler and a rear muffler, both are straight through though. And I do have a cat, it's a 100 cell high flow, 3 years old now. I've smacked it though and it didn't rattle so I don't think it's rooted.

Yeah the graph picks back up to around peak power right at redline, so something funny is definitely going on.

It's in road speed because my old boss (who owns the exhaust shop where I dynoed it) reckoned that he needed to put an inline injector plug adapter on to get rpm. Which I thought was odd because I've got other dyno dynamics dynos in rpm and there were no injector plugs used then.

I'd say that 120kmh is actually around 4500rpm, so I have no idea why it hits a wall there...on the dyno VVL was set to 5000 intake 5300 exhaust, which might well be where the graph picks back up like crazy. Right now I've changed it to together at 5000. Feels much the same.
Maybe I will change it to together at 4500 and see how that feels, as well as unplug them and see how it runs. I'll get my girlfriend to bring her 180sx out so I can actually see if it's making a difference to the speed.

In any case, I think the first thing I will check is to go WOT with the laptop in and see what MAF values I get. I hope it goes to 5V and that's my issue. Haha. Easy fix.

Also @gio94sr20ve the plugs are less than 1000km old, they were brand new on the dyno. Not sure why the boost graph is all jagged? It was running off the gate with a baby baby bit of manual boost controller wound on.
At the moment the controller is all the way out and the car is peaking at 11psi.

I'll also see if I can increase the load to 90 or so. When the car was n/a it used to trace through 56/60.

Setup.