[TT_6SPD_95]

Just wanting to get some feedback on anyone who has done between 500-550rwhp before and after cam dyno runs? Anyone done this? Thanks, your help is very appreciated.

 

[Guest]

Most of the member's on this site have unopened engines (stock internals), so I doubt you'll get an "experience" response, but who knows, there's prolly someone on here I don't know. I'm sure by doing this you would see a considerable hp increase (probably around 30 hp), but the most important thing that would result out of this, would be that it would make your engine be able to handle more boost, which is all we want right? MORE BOOST!!

 

[Guest]

Tony, if you don't mind could you tell me exactly what you have done to your car to run those times.

Thanks
Phil

 

[element217]

Tony, if you don't mind could you tell me exactly what you have done to your car to run those times.

Thanks
Phil

If you go to his website, theya re all listed.



Tony_

I installed cams and did not see a hp gain but saw a huge gain in torque. The cams were never tuned for power though, as they were tuned for idle, so who knows.


stephen

 

[TT_6SPD_95]

If you go to his website, theya re all listed.



Tony_

I installed cams and did not see a hp gain but saw a huge gain in torque. The cams were never tuned for power though, as they were tuned for idle, so who knows.


stephen

Thanks for the response. Would you happen to have any dyno runs that I could see to compare before and after. I would really appreciate it. If you can't post the sheets, what numbers did you do before and after...both hp and tq. Thanks.

 

[RSA Supra]

If you look in the parts section, you'll see that I'm selling some barely used 264's for a friend of mine. He is happy with the power that he'll be able to make with his T04R w/ out the cams.

I think you get the most power from cams when you do headwork and valves, but you should gain torque and likely spool the turbos up better with the cams. It will make the car sound really nasty. :evil:

 

[Steve Jarvis]

Cams will flow more air which could increase your peak torque, but your hp probably won't go up if your on stock twins. I don't this the stock twins can push enough air to use the extra flow on the top end. Spool up is typically slower.

Of course this is all theory, so it would be interesting to see.

Later, Steve

 

[TT_6SPD_95]

Thanks for all the responses everyone.

Ryan, did he try the 264's on the stock twins? What power levels was he making first, and then did he gain anything? Thanks.

 

[RSA Supra]

Thanks for all the responses everyone.

Ryan, did he try the 264's on the stock twins? What power levels was he making first, and then did he gain anything? Thanks.

He threw them on with the 60k service after he did the single, so I don't know. I'm not sure if anyone's run cams on stock twins.

 

[John H]

Geez, it always amazes me how people give false advice on topics they know nothing about.

For the most part, Steve is on the ball and running with it.

To make corrections (to others), turbo spool will always decrease. For 264s the average is a 500rpm later spool. Larger cams will not increase the amount of boost your engine can handle. No one has ever posted an actual dyno sheet or given a dyno account of different cams on a stock twin car and I've been reading all the Supra crap since before the MKIV list, i.e. SOGI.

Tony, if you want to be a pioneer, I would opt for the HKS 254 cams. 264s are more than plenty for even the output of the largest twins/singles. On stock twins the gain would be minimal, but with the obvious flow your turbos are making, the 254s should give an increase. Over 15rwhp? Not likely. 10-15rwhp? Maybe. The increase in peak torque will be higher as Steve noted, but the torque under the curve will decrease as the peak torque will be higher in the rpms.

Another very interesting aspect which I'm not sure if you've taken into consideration is your use of nitrous. The larger cams will definitely increase your rwhp while on nitrous as opposed to running stock cams.

John H

 

[TT_6SPD_95]

Geez, it always amazes me how people give false advice on topics they know nothing about.

For the most part, Steve is on the ball and running with it.

To make corrections (to others), turbo spool will always decrease. For 264s the average is a 500rpm later spool. Larger cams will not increase the amount of boost your engine can handle. No one has ever posted an actual dyno sheet or given a dyno account of different cams on a stock twin car and I've been reading all the Supra crap since before the MKIV list, i.e. SOGI.

Tony, if you want to be a pioneer, I would opt for the HKS 254 cams. 264s are more than plenty for even the output of the largest twins/singles. On stock twins the gain would be minimal, but with the obvious flow your turbos are making, the 254s should give an increase. Over 15rwhp? Not likely. 10-15rwhp? Maybe. The increase in peak torque will be higher as Steve noted, but the torque under the curve will decrease as the peak torque will be higher in the rpms.

Another very interesting aspect which I'm not sure if you've taken into consideration is your use of nitrous. The larger cams will definitely increase your rwhp while on nitrous as opposed to running stock cams.

John H

Thank you very much John for the info. That helps out greatly.

I am just curious as to why people use 272's on the big singles and say that 264's are for the smaller singles?

Corrrect me if I am wrong please, but aren't the stock cams 22X intake and 233 exhaust?

On the peak torque subject.....my peak torque now comes from about 4400rpm, so if I did 254's that torque peak would move to 4900 or so is what you speculate?

Thanks for the input John, I am just trying to get everything I can out of the stock twins to do 10's without the aid of nitrous. If I do cams (which I am not sure of yet) the next step would be to maybe get a lightweight flywheel. What do you think the gain would be with just that alone?

Sorry about the long post. Thanks for all the input, it is very appreciated.

 

[burnmacs]

If your goal is 10's on stock twins how about you hard wire the wastegate shut. Talk to Chris Bergemann about this one, he was running 2 bar on the stock twins and said it pulled like his T-78. Unfortunately a BOV hose popped off killing the twins en route to the track.

 

[RSA Supra]

Geez, it always amazes me how people give false advice on topics they know nothing about.

I assume you're talking about me...

I think you get the most power from cams when you do headwork and valves, but you should gain torque and likely spool the turbos up better with the cams. It will make the car sound really nasty.

Cams are not something I know nothing about, but I don't know a whole lot. That is why I qualified my comment with I think rather than irrefutably.

Regardless, yes you are correct they will cause more lag due to less air velocity. What I should've said was, that they should help spool the turbos at high end because they will flow a little better, but again with stock turbos and even stock heads, you're not likely to see much improvement. You are correct in stating that the 254's are probably the only thing that Tony should consider. On a big single, a car will probalby get 30rwhp w/ out tuning from the 264's. But with stock twins, probalby won't see much more than 10-15rwhp with either cam.

 

[TT_6SPD_95]

If your goal is 10's on stock twins how about you hard wire the wastegate shut. Talk to Chris Bergemann about this one, he was running 2 bar on the stock twins and said it pulled like his T-78. Unfortunately a BOV hose popped off killing the twins en route to the track.

I might try doing the HPF mod, but I am very close right now without the extra boost...I am doing 20lbs at the track now. Once I get to the 10's without the extra boost then I will do the HPF mod and see what I can do then. At that point I will just be waiting for the stock twins to run out of breath...not sure when that will be though.
After the stock twins go out I am going to do a single turbo upgrade and have another goal then.

 

[Lagtime]

I wonder if a longer duration cam on the exhaust side wouldn't exacerbate the potential problem of exhaust gas reversion into the cylinders. Cars on stock twins have a huge pressure ratio, one of the reasons I suspect so many BPU cars run better on high octane fuel, reversion due to backpressure causing the incoming A/F mixture to preignite. Higher octane gas helps prevent this.

If you hold the exhaust valve open longer, on a setup that already has trouble flowing (the stock exhaust manifold and stock turbo exhaust side) you may end up with more exhaust flow back into the cylinder, rather than better cylinder emptying on the exhaust stroke.

I must admit my thoughs are that area under the curve will suffer on a stock twin car with bigger cams since the stock turbos won't flow to the capacity of the stock head/cams as it is.

 

[Guest]

Good thoughts. I doubt there is any power to be realized by going with larger cams on the stock twins. Maybe an HKS 248/256 combo, but doubtful. If you want to make more power on the stock twins, port and extrudehone the stock exhaust manifold and hot side of the turbos. This is the first restriction, cams are second.

 

[Grant]

I wonder if a longer duration cam on the exhaust side wouldn't exacerbate the potential problem of exhaust gas reversion into the cylinders. Cars on stock twins have a huge pressure ratio, one of the reasons I suspect so many BPU cars run better on high octane fuel, reversion due to backpressure causing the incoming A/F mixture to preignite. Higher octane gas helps prevent this.

If you hold the exhaust valve open longer, on a setup that already has trouble flowing (the stock exhaust manifold and stock turbo exhaust side) you may end up with more exhaust flow back into the cylinder, rather than better cylinder emptying on the exhaust stroke.

Agreed. After looking the size of the turbo flanges on the exhaust manifold, and the size of the turbos themselves, I now believe that spending lots of money and time on the stock twins is a complete waste.

 

[John H]

Ryan, it's ok. :beerchug:

Tony, the 256 cams shouldn't affect your torque curve by 500rpm. That's just the average when using 264. Obviously it should be less with the smaller cams. To my knowledge, no one has installed anything smaller than 264s on a 2JZGTE and reported about it.

On the lighter flywheel subject, I wouldn't recommend this for you since you mainly dragrace. I didn't figure you roadraced much since you drive around on ET Streets. With the lightweight flywheel, you lose the launch inertia the heavier flywheel gives you. It's also pretty tricky to launch and the flywheel will tend to overheat on repeated launches. I don't have extensive first hand experience with this, but the launch inertia is common knowledge with any car and the overheating I've heard from a few sources including Chris Rado. The lightweight flywheel will give a BPU car about 1-2 mph in the 1/4 though.

Walser/Darren's advice on extrude honing and (port matching) the exhaust side of the turbos to the manifold is solid advice. I would have done this a long time ago, but by the time you take everything off, you might not want to put it back on.

On the wastegate mod, you might not get too many chances to run 10s before the turbos self-destruct. Chances are very high it wouldn't even last the first attempt. The backpressure in the engine has to be insane at 2 bar with the stock turbos/exhaust manifold. You would have to be a dumbass to do that.

I think the only thing not mentioned would be to extrude hone the stock intake manifold. Negligable gain, but a gain non-the less. I don't think anyone has done this on a stock twin car either. If a VPC w/o tuning gives an increase on stock twins, theorectically this should as well - regardless if the exhaust side of the engine is the restriction. The exhaust side just gives larger gains.

John H

 

[RSA Supra]

John, :beerchug:

Both manifolds were extrudehoned on my car before I bought it, so I don't know what gains they gave.

As far as trying to run 2bar of boost. It's been done bofore, but I'm not sure how much help it would be because the turbos are working so inefficiently at that point that the intake charge would be very hot. Mani hit 2.17 bar a few times but said the car didn't feel any faster than @ 1.6 and then a few weeks later lots of smoke started coming out of his exhaust.

I suppose with a big FMIC that has been iced down, you may be able to keep things in check long enough to make it down the track @ 2 bar.

 

[pooshda]

2 bar on stock twins is insane, thats about all I have to say though... And ive killed two sets last year alone, Stock twins scare me... I would hate it if I need to put those back on in order to get my car operational by summer... might happen though, I think Id rather keep it put away in the garage than put stock twins back on...