MK3 Supra Turbo looking to Upgrade??

[bradenman1]

Originally Posted by turbophil

Hi you dont say what engine I take it it's a 1j, a 3" system will loose power down low and not make any more up top than a 2.5" system, we dont use 3" untill the motor makes over 500Hp, make up your mind if you want to be into fashion or power. forget about shiney "Look At My" bits they wont work well on the street.I have a 91 r spec with full GReedy set up, Trust Headers, TD07 ARC intercooler and all the rest of the best bolt on's from japan. It's a dog down low and while great fun, is not a streetable car (triple plate etc) Buy parts that will work for what you what if it to show off but the shiney bits. Phil


Where there's a Phil There's a way

No I have a mk3 supra the standard engine for the mk3 is the 7m series. I have a 7mgte.

Sorry it took me so long to reply I wasn't notified that someone posted.

That's funney iv heard the opposite everywhere iv been. On a turbo cxar biger is better to allow the exhaus to escape faster and to alow scavenging to occure in the piping. The more free your downpipe and exhaust is the faster your spool is because there is leas back preasure. The faster you can spool up the quicker you get your power. I have also been told that you can see gains of 1-3 psi and 30+ horsepower just from a 3" high flow exhaust.

Someone correct me if I'm wrong please

[Supra Saiyan]

I don't know if your wrong or right.. I hope it is true.. Sounds true enough..

[cre]

Originally Posted by bradenman1

Someone correct me if I'm wrong please

Ok... well, yes and no... Larger pipe HURTS scavenging... severely. The larger the pipe the lower the velocity and the more time gases have to cool and increase in density thus requiring more energy be expended to expel them. BUT, scavenging isn't terribly important in a forced induction setup.... it is fo a N/A application which is why you'll hear a lot of mechanics and tuners telling an N/A owner they're a dope for running a 3" or larger exhaust, too large a throttle body or intake piping. Scavenging is a where the high velocity of the gasses flowing through the exhaust create a suction which, if employed correctly, assists in the removal of exhaust gases from the combustion chamber on the exhaust stroke... in a turbo setup this simply is not possible as the gasses must be pushed in order to move the exducer. The turbo's exhaust, especially after the turbo, is much cooler and much denser thus it requires more room to flow without creating back pressure.... and no matter what you may have heard; BACK PRESSURE IS NEVER A GOOD THING!

[Supra Saiyan]

Originally Posted by cre

Ok... well, yes and no... Larger pipe HURTS scavenging... severely. The larger the pipe the lower the velocity and the more time gases have to cool and increase in density thus requiring more energy be expended to expel them. BUT, scavenging isn't terribly important in a forced induction setup.... it is fo a N/A application which is why you'll hear a lot of mechanics and tuners telling an N/A owner they're a dope for running a 3" or larger exhaust, too large a throttle body or intake piping. Scavenging is a where the high velocity of the gasses flowing through the exhaust create a suction which, if employed correctly, assists in the removal of exhaust gases from the combustion chamber on the exhaust stroke... in a turbo setup this simply is not possible as the gasses must be pushed in order to move the exducer. The turbo's exhaust, especially after the turbo, is much cooler and much denser thus it requires more room to flow without creating back pressure.... and no matter what you may have heard; BACK PRESSURE IS NEVER A GOOD THING!

So if you have a turbo you would say 3in exhaust is good, and NA should not be that large.. Like 3in.. lol..?

[turbophil]

Sorry you are wrong, the size of the pipe after the turbo on a STREET driven car is very important The flange on the turbo back to the under the car (First 1.5 /2 meter) is very important and dispite what you have read, i have proven it many times on the dyno but in fairness as the engine gets larger the effect is less, I stand by my comment that most people buy things that dont suit what there are doing but thats the power of advertizing (God bless America) LoL Phil

[kamikazemkiii]

Ive got a 3inch downpipe if you need one

[turbophil]

Sure your right but thats is all I'm doing, Im sure members can take from it what they will Thanks Phil

[Raysupra]

from some personal experiences My friend took his stock 1j and put a nice 3" exhaust on it and he definitley saw hp gains and boosted from 12psi to 15psi hitting cut somewhere now and it sounds very nice and spool is very smooth and fast. I would recommend a 3" exhaust For any inline 6 as to be Perfect i think a 3.5 is to big.. but i have yet to drive with one to compare.. 2.5 seems a tiny bit to small for my needs and hp wants

[turbophil]

From personal experiance, my mate ??? did he try a 2.5 system? no, so HOW can you make this statment, he may well of got the same result and what sort of expert are you to advise people to fit a 3 " system? I know a guy who had a freind who knew a guy ........

[Raysupra]

i drove the car. im not saying 2.5 is bad but he say hp gains to the 3"