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Oldie but a Goodie
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Discussion Starter · #1 · (Edited)
Well... i took my car to my dad's shop today to put it on the dyno to see if we could find out what's going on with this turbo whine. No matter what we couldn't hear the sound in the shop. Used a nice long and thick prybar placed on the turbo housing and couldn't hear any noise/vibrations and the turbo still spools fine and holds boost well (10psi).

Next thing i need to do is go through and check all the exhaust gaskets to make sure there is no leak... it is quite possible that a certian someone (myself) could have caused this problem by using a certain high performance sealing device, otherwise known as "cardboard," as gasketry for the new testpipe :dunno: .

Anywho! After finding that the turbo seems to be ok, we went ahead and did a dyno run to find out how the test pipe benefits the car vs. having a cat on.

Old numbers: 257hp/292 ft.lbs tq

New numbers: 328hp/304 ft.lbs tq

I'm a bit baffled as to how the hp surpassed the tq figure but i'm fine with it the way it is. Everything was identical from run to run except i replaced the stock cat with a 3inch test pipe and swapped the old lower IC hoses with a single hardpipe. Both runs at 10psi.

Hp should also be a tad higher for peak, my dad cut out at 6200rpm and it was still climbing. He forgot where the rev limiter kicked on and backed out early.

overall... I F***ING LOVE THIS TORQUE CURVE... err rather torque LINE!!!

I am most certainly glad i chose the 50 trim for the CT. Dyno sheet to be posted within the next 10 minutes.

*edit mods are in the sig* - CAT - stock lower IC hoses + testpipe + lower IC hardpipe



I appologize for how light the coloring is, i should have darkened the image. If you want to compare to the previous dyno sheet just click on the link to my webpage or i'll post it up again as well.
 

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Chrisco said:
Well... i took my car to my dad's shop today to put it on the dyno to see if we could find out what's going on with this turbo whine. No matter what we couldn't hear the sound in the shop. Used a nice long and thick prybar placed on the turbo housing and couldn't hear any noise/vibrations and the turbo still spools fine and holds boost well (10psi).

Next thing i need to do is go through and check all the exhaust gaskets to make sure there is no leak... it is quite possible that a certian someone (myself) could have caused this problem by using a certain high performance sealing device, otherwise known as "cardboard," as gasketry for the new testpipe :dunno: .

Anywho! After finding that the turbo seems to be ok, we went ahead and did a dyno run to find out how the test pipe benefits the car vs. having a cat on.

Old numbers: 258hp/292 ft.lbs tq

New numbers: 328hp/304 ft.lbs tq

I'm a bit baffled as to how the hp surpassed the tq figure but i'm fine with it the way it is. Everything was identical from run to run except i replaced the stock cat with a 3inch test pipe. Both runs at 10psi.

Hp should also be a tad higher for peak, my dad cut out at 6200rpm and it was still climbing. He forgot where the rev limiter kicked on and backed out early.

overall... I F***ING LOVE THIS TORQUE CURVE... err rather torque LINE!!!

I am most certainly glad i chose the 50 trim for the CT. Dyno sheet to be posted within the next 10 minutes.
Those are some really good numbers..
 

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Wu_Tang said:
wow...i didn't think the cat restricted that much hp...very nice indeed.
It's the stock cat, and I believe it. An aftermarket high-flow 3" cat was only $40 at Summit, and woke my car right up when I built the cat-back. That is in addition to the BIC downpipe.
 

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Oldie but a Goodie
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Discussion Starter · #8 · (Edited)
Twigger said:
I find it hard to believe that removing the cat gave you 70hp. but good numbers.
I thought the same thing when i first saw the numbers... i was hoping for close to but not at 300.. I'M VERY MUCH PLEASED with how things resulted though. And as i said in the first post, if you want to compare the two dyno sheets just look at my webpage (link in teh siggy) or i can post up the other dyno sheet, just let me know.

And thanks for all the good replies :bigthumb: 7m power.com still have the 300hp minimum?

*edit*
OH SH*T! i completely forgot that i did actually ad one other mod. replaced the stock lower IC hoses with a single hardpipe. That would aid in the hp increase. Many appologies for the missleading information. Fixed the first post too.
 

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Oldie but a Goodie
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Discussion Starter · #12 · (Edited)
tiki240 said:
whats ur full mod list?
see first post.. and they're all in my signature except for the test pipe and lower IC hardpipe, but i suppose i can post them more formaly.

Only engine mod is a rebuilt longblock from Jasper engines and transmissions... stock build.

other mods are:

upgraded CT to to4e 50trim shimmed to 10psi
dirty ass K&N filter
Lower IC hardpipe
3inch turbo-back exhaust.

everything else is suspension related except for the rear end, but those are all of my power adders.
 

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nice numbers...

as for your question about hp beating out tq...

did you keep an eye on the boost gauge? my guess is you are experiencing boost creep... which is how you get more hp then tq...

you get max tq down low...BUT because your target boost is surpassed as the engine rpm increases the hp increases but youve already hit your max tq...thats how you get numbers like that....

so check your boost gauge when you run it up sometime...ill bet it spikes up to around 13-14psi before the gear is done...

EDIT: oh and from your AF curve..you would GREATLY benefit from an afc and some tuning..looks to be another 20-30hp in there easily...
 

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Discussion Starter · #14 ·
psifactor said:
nice numbers...

as for your question about hp beating out tq...

did you keep an eye on the boost gauge? my guess is you are experiencing boost creep... which is how you get more hp then tq...

you get max tq down low...BUT because your target boost is surpassed as the engine rpm increases the hp increases but youve already hit your max tq...thats how you get numbers like that....

so check your boost gauge when you run it up sometime...ill bet it spikes up to around 13-14psi before the gear is done...

EDIT: oh and from your AF curve..you would GREATLY benefit from an afc and some tuning..looks to be another 20-30hp in there easily...
Well I did a couple 3rd and 4th gear pulls to check on the boost creep. Turns out that yeah it is doing it, but for some reason it doesn't in 5th?? Or maybe i just hadn't reached high enough rpm for it to (didn't feel like going over 120).

How does boost creep occur? i'm assuming it has to do with the wastegate spring losing tension or something of the sort.

And yeah i can't wait to tune it. Looking into the MAP ecu as we speak... err, rather as i type this ;)
 

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Chrisco said:
How does boost creep occur? i'm assuming it has to do with the wastegate spring losing tension or something of the sort.

And yeah i can't wait to tune it. Looking into the MAP ecu as we speak... err, rather as i type this ;)

Its because you have your wastegate shimmed and the spring is probable a bit on the weak side to. Get a good MBC it it should be cured.
 
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Nice #'s Chris!! I need to bring my Supe down to school so we can race. :D
 

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Buttmunch said:
Its because you have your wastegate shimmed and the spring is probable a bit on the weak side to. Get a good MBC it it should be cured.
id be willing to bet the opposite actually...a weak spring will cause the actuator to open up prematurely and causing boost drop off...

boost creep is usually caused by exhaust gasses not able to exit the WG fast enough...so they choose the main exhaust instead of the "trap door" this in turn raises the boost... hence boost creep...

sooooo my suggestion to cure this would be to port out the wg hole on the ehxuast housing... you can make it about 32mm IIRC without having to move to a larger flapper...

ill bet this will correct any boost creep issues you are having...
 

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if you shim the waste gate u compress the spring and make it stiffer. So that may attribute to the boost creep.
 

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nice numbers. I have a death whine of my own but its coming from the alternator. Only a year old and the bearings are already shot. Belt tension was correct too.
 
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IdealSupra said:
sooooo my suggestion to cure this would be to port out the wg hole on the ehxuast housing... you can make it about 32mm IIRC without having to move to a larger flapper...
I would NOT recommend this. The wastegate holes are already notorious for cracking and thinning the wall there would only make this worse. Trust me, you dont want a bunch of cracks around your WG hole cause it makes boost controll a real PITA.

You should not be having creep issues and I would look for other problems. Perhaps try unshimming the actuator and run a cheap MBC as stated above. Also make sure your WG flapper isnt binding up or anything.
 
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