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Turbo 3.1L lack of power


djz

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Warning - huge post follows.

 

I wanted to get some input on my setup and how much power I should be expecting, I feel that it is a lot lower than it should be putting out. To be honest the engine was built cheaply and assembled by me, it has run very well for the last 2 years and I have always driven it hard but it has never made the power I thought it should have made.

 

The engine is made up of:

N42 block, 3.5mm overbore

Z24 standard cast pistons 0.5mm oversize

L20ET rods

LD28 crank

N42 head with a minor clean up of the ports, I'm not really sure whether it was done very well or not, the sharp edges in the combustion chamber were removed as well.

Cam was reground 212 degrees @ 0.50 lift and valve lift of .439/.437"

Stock exhaust manifold that had a minor cleanup

Inlet manifold is stock except for a minor cleanup, stock dual butterfly (Jap spec) throttlebody

Pallnet fuel rail, 444cc injectors

TA51/T04 hybrid turbo (the compressor side is probably a bit too big for the motor)

2.5" crush bent exhaust (too small I know)

HKS T3 to T4 adaptor with built in wastegate

Large intercooler & 2.5" plumbing, blow off valve

The ECU is a Link stand alone

 

There's probably a few things I've forgotten and I'll add them if I remember them. The car has been tuned on the same brand of dyno twice at two different workshops, once when the engine was built with a smaller T04 turbo and smaller injectors it made 278whp on 12psi, and again a few weeks ago with the new turbo and bigger injectors it made 288whp on 14.5psi. I completely trust both workshops.

 

Can anybody think of anything obviously wrong with my setup? Below are the dyno charts from both dynos. The last one is in PS and not HP but it works out at about 288hp.

 

Any help would be muchly appreciated.

 

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That does seem low considering what ive seen other dyno claims are of otherwise stock l28ets and similar boost levels. My only guess would be that exhaust. Ive seen people claim wonders with a 3" turbo back exhaust (In particular the downpipe). Keep us updated if you ever get this thing making the power we all think it should be making.

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Im thinking your not even touching the effeciency range of that turbo as well as your restrictive exhaust. That sounds like a rather large turbo for your setup. Might want to go back to the drawing board, research what turbo would be best for your application and go from there. Also look at full mandrel 3" exhaust and tuning.. what is your timing table? what AFR's are you at when WOT? there are many factors in getting your cars full potential..

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Gabe - Is definitely on the right track. A well made mandrel 3" exhuast is going to uncork a grip of power. Plus as Gabe mentioned what are your AFRs? Basically you are at 300whp which is decent but there is definitely much more to be had especially as you have a Link ECU to play with.

 

Please share some pics of your set-up.

 

Yasin

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Thanks guys, I've been meaning to redo the exhaust for ages but have always ended up spending the money elsewhere. AFRs I'm not too sure about, I never asked the guys that tuned it and they aren't on any of the dyno charts I have.

 

I'll take some pictures later on today - its not much to look at. And I'l get a screenshot of the timing table too.

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Bigger cam and a port job rather than just a clean up. The lift on that cam is awfully low in my opinion. For a hot turbo setup I would get closer to .5" lift. If you have seen Big-Phils l28ET dyno video, it is a perfect representation of what a port job can do. He did something like 25psi or something @ 320-340hp I think? Maybe it was closer to 400hp. His buddy Chris has a built up motor with a ported head and did around the same power but at 17psi.

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Bigger cam and a port job rather than just a clean up. The lift on that cam is awfully low in my opinion. For a hot turbo setup I would get closer to .5" lift. If you have seen Big-Phils l28ET dyno video, it is a perfect representation of what a port job can do. He did something like 25psi or something @ 320-340hp I think? Maybe it was closer to 400hp. His buddy Chris has a built up motor with a ported head and did around the same power but at 17psi.

 

This is not the problem and Big Phil's setup is not a "perfect representation" about improvements from a port job. I am not knocking Phil's setup, but even he admits that his tune was not the greatest. Phil was running 100% methanol and did not tune for it. He has a stock intake and a stock P90 head. As a result he was running pig rich and leaving quite a bit of power on the table.

 

http://forums.hybridz.org/showthread.php?t=131896&highlight=dyno

 

I am running a stock F54 turbo block, stock P90a hydraulic lifter head, stock N42 intake, 440 cc/min injectors (flow benched at 503), T03/04E 50 trim turbo (similar to a Holset HY35), and methanol injection (quite different from Phil's setup though). I put down 390 wheel ft-lbs of torque which is identical to Phil and the same power at 20 psi . I am now boosting to 22 psi that increases to 24/25 psi after peak torque to address the power falling off. I am also running 1400 cc/min methanol injection versus the 700 cc/min I ran at 390 ft-lbs, all on a stock block, stock head and stock intake.

 

Again, stock block, stock head, and stock intake.

 

Edit: Addressing the OP, I agree with what gabe and yasin are stating.

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This is not the problem and Big Phil's setup is not a "perfect representation" about improvements from a port job. I am not knocking Phil's setup, but even he admits that his tune was not the greatest. Phil was running 100% methanol and did not tune for it. He has a stock intake and a stock P90 head. As a result he was running pig rich and leaving quite a bit of power on the table.

 

http://forums.hybridz.org/showthread.php?t=131896&highlight=dyno

 

I am running a stock F54 turbo block, stock P90a hydraulic lifter head, stock N42 intake, 440 cc/min injectors (flow benched at 503), T03/04E 50 trim turbo (similar to a Holset HY35), and methanol injection (quite different from Phil's setup though). I put down 390 wheel ft-lbs of torque which is identical to Phil and the same power at 20 psi . I am now boosting to 22 psi that increases to 24/25 psi after peak torque to address the power falling off. I am also running 1400 cc/min methanol injection versus the 700 cc/min I ran at 390 ft-lbs, all on a stock block, stock head and stock intake.

 

Again, stock block, stock head, and stock intake.

 

Edit: Addressing the OP, I agree with what gabe and yasin are stating.

Well I guess it just depends on what sort of money he is willing to spend because no one can argue that a port job will kill his power, and I still think that cam is a bit small compared to some other turbo cams. If he is going to go through the trouble of changing some stuff on his turbo, exhaust, and maybe intake, then by that point it is a good time to change out a head while everything is off of it. And I still think the head is a problem, it is always a problem until you have it ported. Note the guys who have built NA stroker motors without a port job and they only make 180-200hp. Port it and you bump up to 260-270hp hopefully. Well now force 17psi or whatever through it, the gain is even better. Like I said, if he is willing to dish out the money, and apparently he is to a certain point if he had some good people build it (unless you received some great deal), then he can dish out another $1500-$2000 for a cam and port job or just $1250 for a port job. Big phils situation, if you take out the methanol and add a good tune, it would be the perfect situation, sorry for stating it improperly. The port job still prevailed in the dyno runs.

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Porting is not the answer for his power issue. Porting is not the answer for everything. Installing a cam is not the answer for everything. Changing intakes is not the answer for everything.

 

If he was asking how can I make more power, then yes, porting could be an answer. He is asking why do I seem to be down on power.

 

Again, Phil and I are making some nice power on a stock long block. Yes, we could be making the same power with less boost by allowing the engine to breath easier, but the fact remains we are making nearly (if not over by now) 400 ft-lbs on a stock long block.

 

To the OP: We are looking at power curves. Do you have a plot of your torque and power together?

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Thanks for all the input guys, a couple of you have pretty much nailed what I was thinking, people are making just as much power and in a lot of cases more than I am with stock blocks and heads, it just makes me think that something in my setup is very wrong.

 

Anyway, here are some pics, as I said it's not much to look at and I went in a Grasskhana on the weekend that was more like a dirtkhana so everything is covered in it, had to make some last minute repairs after one of the radiator fans failed so thats what the messy wiring and cable ties are. The car is a 1978 280ZX, converted to 5 stud all round, R32 Gts-t calipers up front, Z31 brakes and half shafts in the rear, R32 Gts-t gearbox and clutch, R31 LSD, '83 R&P powersteer.

 

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Ignition.jpg

 

And a little movie of the dirtkhana if anybody wants to watch my terrible driving, it was my first time actually racing my car in any sort of event.

 

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I don't think my general point isn't getting across properly. I am keeping with my porting logic, not so much the cam although I do think a little bit bigger would be good. My point is that sending so much pressure into that motor like that to get maximum number, to me, I don't find the very reliable. I would rather take the time to properly setup a hot head and make the same power but at a lower pressure because one bad habit that Big-Phil has/had which I think some are forgetting or avoiding is that he went through motors quickly. I think all the answers are valid to the original question "Can anybody think of anything obviously wrong with my setup?"

 

Goodluck with your progress.

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Several have already mentioned it, but...

Airflow, Airflow and Airflow. The exhaust is a problem, and have you done any work on that intake manifold? There are usually several casting protrusions into the plenum and the runners that make for funky flow characteristics, and how big is that TB again?

 

Also, I'm not sure there's much you can do about it short of modifying the end tanks, but that IC design is requiring more tight 90's in the plumbing than I'd like to see.

 

Have you measured the air temps at the intake manifold? It would help to know what air temps you are seeing at WOT and full boost. I see that you are running a heatshield between the intake and exhaust manifold which is good, but your air filter placement is drawing hot air from the engine compartment and making your IC have to work that much harder to get the temps back down. I know that this is also not that easy to solve, but your crossflow IC should leave some room to draw the air from the front.

 

It would be good to have a wideband for tuning the AFRs, too. What are you currently using for an EGO sensor?

 

Have you checked the timing on that reground cam?

 

That IS a good looking ZX, BTW!

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