Up-pipes

[STIGR-Wagon-Dad]

My set up is a vf48 with an HKS equal length manifold mated to a Grimmspeed up-pipe. It works well but I am going to run a Steam STX 76. I originally was going to use a Perrin big tube up-pipe but the outlet was slightly smaller than the turbine inlet. I decided to go with a GTSpec up-pipe to have a better match in diameter. Am I going in the right direction? Based on my last turbo car which was a 88 Celica All-trac turbo, which has the turbo right at the exhaust ports and port matched, I figured to try to get the ports to match as close as possible. The Grimmspeed matched the stock turbo perfectly and I would think that it would help with the manifolds ability to improve the bournoulli effect at the collector, by using a slightly bigger up-pipe that matches closely to the manifold and turbo. The turbo is equivalent to a gtx 3076 with a mitsubishi 9 blade turbine with a 10cm turbine housing, GTX 3076r style comp wheel with a 3 inch compressor inlet.

 

[HolyCrapItsFast]

I think you are on the right track if not for matching the ports alone. Since you have headers, you have increased the flow and have allowed the use of a larger pipe. With a turbo that large, I would always recommended headers and an up pipe as well as a very unrestricted exhaust. I might even have recommended a set of cams to help increase the exhaust load.

With any turbo, the key to good spool is the velocity of the exhaust gasses supplying the turbine. The mistake many people make when selecting up pipes is they automatically think bigger is better when in fact it has the totally opposite effect as desired because a larger pipe decreases the flow velocity. Only a proper setup requires a larger up pipe and that includes anything that will increase the flow. It sounds like you have done that.

 

[STIGR-Wagon-Dad]

Thanks, Holy! Majority of my experience is mainly 4ag powered toyota. My short time with the Celica was only less than a year and I was only 20 yrs old at the time. The celica was stolen before I could learn anything about it(and the Internet wasn't around to do some research). I figured by having the collectors scavenging effect take place and having a port matched uppipe maintain velocity, and have it big enough to flow for the power to spin the turbine. Supposedly the mitsubishi 9 blade is lighter, spools quicker, and outflows the Mitsubishi 12 blade, the EJ257B produces high back pressure and i want to take advantage of it. I am going catless also, and with the help of a 3 port ebcs, synchronic dv, and tune, I'm expecting this turbo to spool quicker than the other turbos comparable to it. I was thinking about running the dc sports downpipe because it is the only one that has a shallow merge with the iwg pipe to the main 76mm pipe. I appreciate your experience in the matter. This is my first bigger turbo swap.