Thoughts on this dyno graph, is my power being restricted?

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The cooler is 650x300x55 with ordinary end tanks on it.
The 3RZ is a truck motor, so yes designed to make heaps of torque.
I suppose there is only one way to find out.

[oldcorollas]

hmm, you are losing 10% torque from 4000-5700 ish..
if it was flat, it would be all you could hope for

for power, cos you are losing torque, the poer could be 10% higher at max rpm... but it doesn;t look that bad
from 4000 to 5700, you are increasing flow (hp) by 33%, whereas ideally, you would increase by 43% maybe (assuming you are making max torque at 4000)

11.5 is fairly rich.. could the boost + rich mixture be making it harder to ignite?

if you hit cams limit, it should drop off faster. if you hit valve float, it should be similar.. fast change with rpm.

it could be a number of little things adding up, but you are getting 75% of the increase in power from 4000 to 5700 that you could/should be getting..

oh, before you go all spendy on a new IC... measure the pressure drop across it (ie from the piping before and after it) if not much pressure drop no need to replace (unless temps go up)

actually, it would be very informative to hook up two pressure gauges, one to each side of IC, and give it a bootful.. if one goes up faster than the other, then it has issues..

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hrrrrm, getting so many differing comments so far.

For reference, this is the original dyno graph of the car in its prime. I sent this to the tuner to show that the graph is practically showing a similar type of curves. But his not convinced.



So who am i to believe.... getting quite conflicting reports so far.

[oldcorollas]

that second graph was done in 4th gear?
you could try to overlay them... (i just tried, and they are similar shape, but new one loses less up top)

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i worked it out that its done in 3rd gear, and the revlimit is higher (i think its 6500rpm...)

[chris davey]

I know what you are saying about the stock cams being designed for low end torque but that is a n/a motor. As turbo cars will usually have less duration than a n/a car I would see if you can get the specs of the cams. Max lift, duration from .050". Then some smart bugger can analyse it and see if they are a restriction.

Personally, I don't think it is the cams.

Could also get in contact with ARE and see if they modded that 3rz with a relatively stock engine at all?

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Thats what im thinking, the only small change i could is get a cam gear and dial the cams to move the torque bend further to the right of the graph (i dunno how that gets affected with scissor gear drives though....)

I'm hitting up all my 3RZ resources, but most are coming up short.

[oldcorollas]

after a bit of fiddling, i came up with this.

the power is overlayed at actual numbers on the graphs..
ie, new = 305, old = 355 or whatever..

the torque however, i scaled so they have the same proportions...

ie max at max, and zero at zero.

the torque curve is basically unchanged..




this second image is with the power altered proportionally, ie max = max..

so, assuming that the earlier power pull was reading 16% higher... they are basically IDENTICAL!!!

[chris davey]

pics don't work?

[oldcorollas]

your computer sucks they work for me

http://www.materials.unsw.edu.au/~sford/lance2.jpg
http://www.materials.unsw.edu.au/~sford/lance3.jpg

[30psi 4agte]

OC if i could rep you again i would !! excellent effort on the dyno seets mate !

Im with you about the testing for a pressure drop across the i/c core.
LANCE : This is a must do !! As it will give you an instant idea if the i/c is causing any probs or not and allow you to eliminate one possible cause.

I take it you are running a decent exhaust ??? It may be worth testing this for excess back pressure also. Blocked cat / exhaust ???

One thing i dont think was mentioned is the amount off boost you are running ???


by the way 11.5 :1 a/f is about the norm for a turbo car in full flight.

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thanks for that OC.

Ill get some fittings and see what the story is with the pressure drop. But I was always going to buy a bigger intercooler either way.

The exhaust is 3" all the way with no cat, and then splits into 2 x 2.5" squash bent outlets over the axle. I wouldn't think that its the flow restriction.

Boost im running for the 300rwhp run with the gt35r is 14psi. Old setup with T3/T4 355hp was using 20psi.

Curious though with the difference of the first picture between the power curves. The new one is flatter (shouldn't it look the same) instead of more curve like the old setup? Or does that come down to turbo?

I'll send off those pictures and see what the tuner says.

[oldcorollas]

Curious though with the difference of the first picture between the power curves. The new one is flatter (shouldn't it look the same) instead of more curve like the old setup? Or does that come down to turbo?

I'll send off those pictures and see what the tuner says.

the older graph you posted had a peak of 355hp, and the new one has 305.

the first graph just has the 355 grph laid directly over the top of the 305 one, but on the same scale of hp (so you can use the left axis as the scale)
for this first graph, i "normalised" the torque to have the same peak as the new dyno sheet.

the second graph, i "normalised" the old graph to peak at 305hp, and then laid it over.
it is basically identical except where it tails off up top...

so basically.... if the old graph was reading 16% over (or new one is reading 16% under) they are almost identical

edit, what were the differences in setup between the two runs? old graph also done in shootout mode?

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i couldn't tell you what the old graph was done in, as it was ripped straight from the magazine article done on the car way back when.

I posted the same question up on Microtech forums, and Jon from RX Engineering had a look and these are his comments (And if anyone knows what they are talking about its Jon)

That dyno graph looks fine
The power is still going up when the dyno operator has backed off which is telling me there's heaps more left in it.
The turbo is no where near it's full potential yet.My suggestion would be to put some good quality fuel in the tank & take the boost up to 20-22 psi.
The GT35 turbo for some reason on a 4cyl needs that boost to work properly in it's efficiency range
I can't see how from that graph they can figure out there is a restriction somewhere
Can you get a copy of the graph with the boost overlayed also????
You will find that the reason the graph comes up sharply & then changes direction is because the boost is ramping up & then the wastegate opens & the boost is held constant.You will see on the boost graph that the boost will flatten out at the same time the graph changes direction
I could post up 1000's of dyno graphs & they will all be like that.
Once the turbo is "out of legs" or there is a restriction somewhere the HP graph will be similar to what the torque graph is saying there.It will come up,peak & then start go back down again.Your graph is still going up.The turbo is no where near it's potential
Give it some more boost!!!!!!
But make sure you have some race fuel in the tank

[Mr DOHC]

they use pretty chunky valve springs already iirc

the ARE 3RZ is a full-house motor