SR20 gt2871r 91 pump dyno

[Rich260z]

So I just got my car dynoed yesterday (it's still going to the shop it's being built at, and the tq number for me seems pretty low.

I've seen most setups with this turbo put out around the same # hp/tq numbers.

Mods:
sr20det with wiseco pistons/eagle rods
Tomei solid lifter kit with 256 cams
Gt28/71r at 12psi
CR racing top mount T25 manifold (modified by TF Works)
Freddy intake (came with the motor)
id1000 injectors
AEM 320 pump
AEM infinity ecu
Custom intercooler
Stock SR20 tranny with a 3.9 clsd diff

If you need more added to the list let me know. I'm thinking it could be a product of the cam profile, but maybe not. I will be going with flex fuel down the line hence the large injectors and pump. I just want to be able to test out the car and "break it in" without breaking the tranny or anything first, so this is a conservative tune.

If this is normal for the amount of boost, then I'm just an idiot.
http://i995.photobucket.com/albums/af76/Richard316/280zx%20Coupe%20track%20car/Richard%20Day%20SR20dett%202871rs%20infinity_zps6e zzwx6x.jpg
http://i995.photobucket.com/albums/af76/Richard316/280zx%20Coupe%20track%20car/IMG_0770_zpsx7qbitdm.jpg

[brndck]

220ft/lb does seem low imo. how aggressive is the timing map? what fuel are you running currently?

[anthony_240]

Might be that cam profile man


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[Rich260z]

Running 91 in chicago. As for the timing I didn't ask although I do have the map. I'll try downloading the software and opening it up.

[derass]

320whp at 12psi is very good. I think the tubular exhaust manifold and GReddy style intake are to thank for that. Also, I'm very impressed by the increase in powerband from the Tomei 256's. Normally peak power on a stock SR is around 6500, your setup pulls to 7500. I would have only expected that sort of change from 260s. So I would be praising your current cams, not suspecting them.

[Dboyizmlg]

Top mount manifold can decrease to for sure.

What A/R housing 2871r are you running?? .64, or .82?

[Sforteen]

looks like crappy boost control to me, at 4250 is when it looks to hit the WG, then gradually creeps to 12psi... what size spring is in the gate.. imma guess 8-9psi? what are you using for boost control if anything

[TheRealSy90]

The greddy intake manifold and aftermarket exhaust manifold is what's killing your torque, and subsequently helping your HP in the top end.


Go back to the stock intake manifold and you'll pick up a lot of bottom end without sacrificing much top end since you have bigger cams in it.

[Rich260z]

It is a .82 housing. didn't have an option to run a bottom mount manifold as the steering knuckle was in the way, also didn't come with the stock intake manifold so the freddy is staying on.

Didn't think about boost control, the spring is at 9psi.

If this seems appropriate then I'm not complaining. I didn't even think about the manifolds causing that much loss in tq. The intended use of the car is road racing, and once I up the boost on e85 it should be more than enough.

[S14kouki805]

The greddy intake manifold and aftermarket exhaust manifold is what's killing your torque, and subsequently helping your HP in the top end.


Go back to the stock intake manifold and you'll pick up a lot of bottom end without sacrificing much top end since you have bigger cams in it.

I'm no pro but that's exactly what I was thinking

[TheRealSy90]

didn't come with the stock intake manifold so the freddy is staying on.

The exhaust side is understandable due to the chassis the engine is in.


On the intake side you should be able to trade someone for a stock manifold plus cash on their side no problem.

[derass]

looks like crappy boost control to me, at 4250 is when it looks to hit the WG, then gradually creeps to 12psi.
It is a .82 housing.

I disagree with this. That peak at 4250 rpm is when full boost comes on, torque builds from there. 12psi at 4250 is quite reasonable given that OP has the larger turbine housing. My 2871 52T (which OP also appears to have) 0.64 A/R hit 15psi at 4200, and the time/rpm difference between 12 and 15 psi would be lightning quick as the compressor wheel is accelerating very quickly by that point.

The bigger turbine housing really offers any benefit when running these turbos to their absolute max, the 0.64 A/R would have offered a slight increase in torque given this setup. But by the sounds of OP's plans for E85 (and 20+ psi I assume), he will reap the benefit of the larger housing. Those aftermarket manifolds will really shine then too. OP just has to put up with slightly lesser response and torque for the time being.

[NoSk1LLeD]

Hi There,

i am from Germany.

here my setup:

HKS GT RS Turbo (Customized GTX Billet Wheel)
Tomei Exhaust Manifold
Tomei Cams 256°
Tomei Rocker Arm Stoppers
3" Elbow
3" Downpipe
100CPSI Cat
Blitz Nur Spec
Nistune ECU
Z32 AFM
Z32 Fuelfilter
Wallbro Fuelpump
FMIC
etc.

I drive this setup in my S15.
Makes 351PS/468nm.
With the swap to another gearbox, i can do more boost.

I am wondering about your Dyno.
Is this only of your fuel?

My peak is at 2200rpm, full boost at 3780rpm

[Sforteen]

I disagree with this. That peak at 4250 rpm is when full boost comes on, torque builds from there. 12psi at 4250 is quite reasonable given that OP has the larger turbine housing. My 2871 52T (which OP also appears to have) 0.64 A/R hit 15psi at 4200, and the time/rpm difference between 12 and 15 psi would be lightning quick as the compressor wheel is accelerating very quickly by that point.

The bigger turbine housing really offers any benefit when running these turbos to their absolute max, the 0.64 A/R would have offered a slight increase in torque given this setup. But by the sounds of OP's plans for E85 (and 20+ psi I assume), he will reap the benefit of the larger housing. Those aftermarket manifolds will really shine then too. OP just has to put up with slightly lesser response and torque for the time being.

Torque builds with boost i bet boost is just lazy at that point.. be nice if he had a datalog of the boost curve. My personal car makes peak torque pretty much when peak boost is made. it follows the boost curve (initally) almost exactly.. everytime.

[derass]

You're right. I forgot what a turbocharged torque curve should look like. OP should definitely double check his boost control setup. Here's a graph of my pal's car. Just like you said, peak boost and torque happen at the same time.

https://i2.wp.com/www.onpointdyno.com/blog/wp-content/uploads/2014/09/BrandonS13_Meth.jpg?resize=700%2C466

[Sforteen]

A slipping clutch can also produce a simular result...

[Kingtal0n]

Another dyno for the mix
S14 sr20, oem piston, tubular tomei T-25 manifold, gt2871r 64a/r, tomei 256,
approx 16-18psi, pump gas 93

http://i9.photobucket.com/albums/a90/kingtal0n/Recent_tune/alexa_zpsadiw9rsq.jpg (http://s9.photobucket.com/user/kingtal0n/media/Recent_tune/alexa_zpsadiw9rsq.jpg.html)


I think the curve the op posted looks fine for what it is.

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FWIW this is my favorite cheap ($450~) top-mount T3 turbo for daily driver sr20det engines (50 trim compressor, T3 48 a/r turbine). This 9:1 compression, 93 octane, crappy exhaust manifold (worst one I ever saw, custom junk), Ebay intercooler, brian crower 264's, just a bunch of junk and it was absolutely a blast. Top curve was 18-19psi.
http://i9.photobucket.com/albums/a90/kingtal0n/Recent_tune/50trim-sr20_zpsjkvc1vop.jpg (http://s9.photobucket.com/user/kingtal0n/media/Recent_tune/50trim-sr20_zpsjkvc1vop.jpg.html)

[racepar1]

Holy crap! That car's so much cooler than it was last time I saw it! I might have a stock intake mani for you too, getting a CRAPLOAD of SR parts right now. I'll let you know man, LOVE what you've done with the car!

[Rich260z]

I wish I could like that racepar1. Thanks

[bfellini]

Torque and Horsepower should ALWAYS intersect at 5250 RPM's as HP is derived from the torque reading via an equation (HP = Torque x RPM ÷ 5252)... on your dyno plot it crosses much lower so there is some fiddling going on with correction factors or software manipulation...