Thread: Let's talk exhaust housings for a bit

How do you have your adapter set up on your car? I'd like to have a bp gauge with the boost gauge.

I talked to aaron? at full-race today. He agrees that the .78 housing is small. He suggested using the smaller cams as well to see how they react. So I will be doing some datalogging with the VET cams back in there and see if I get better results. If I don't get the results I want, I think I am going to put a .82 housing on there and some valve springs. Rev out to 8500rpm on standard cams and maybe upgrade to the SR16 cams down the road. I can get the response I want if the engine has more revs to work with and I can keep it in the powerband.

.78/2 comes out to a .36 housing. That is really quite small, and verifies what I see in the pics. I could always port the hell out of my divided housing lol.

that whole .78/2 .36 makes sense as to why you felt like the response was better but the numbers werent adding up, it gave you greater response from the smaller housing yet didnt create anymore power over the previous state of the setup, that kinda makes sense.

Well, how would a setup be affected if you went from a .63ar to a .48? It would prob lose 20-30whp (just a guess). It never clicked to me before, but the pulses that go into each scroll now have only half as much space to travel through. The gains you normally see from a twin scroll setup must be from turbine efficiency increases, and not because they flow better.

A 1.06 housing divided would perform like a .63ar, but would make slightly better power and would have better response.

I am going to put in the VET cams and I will let you guys know what happens. I can do some datalogging to see when airflow values are reached, peak values etc. So we can see once and for all the power vs spool between the two cams. I can't afford to have my car on the dyno for 2 hours for testing right now though.

The numbers that people have been able to hit on this housing are pretty impressive though, they just need the right cams, high revs, and more boost pressure. I would not expect the VE to make more power than a DET until crossover occurs and I can take advantage of the head flow. Problem is; on restrictive setups you are not going to see crossover.

I am puttin the VET cams back in right now. I will see how they perform compared to the VE cams on the datalogs. Higher maf voltage=more power. Let's see what happens.

Okay it is all finished up. Had to eat dinner and finished up before the sun went down. VET cams are in. I will let you all know how the spool and power feels. I expect these to spool a lot faster than the ve cams. I will try switching that exhaust cam too and see what happens!

Wish me luck guys!

Took her out tonight. Meh. It builds 15psi by 3700rpm. The exhaust cam made the biggest difference when it switched at around 5500rpm. When the intake switched to 6500rpm you could feel the pick-up. No datalogs yet.

I don't know if you could just feel the intake cam because the exhaust cam was causing a loss of power with it switched?

The top end pull was really really good, and desperately needs more revs on these cams. It seemed to pull pretty good, but not really sure if it runs as good as the VE cams. It is about twice as loud though! It builds the boost faster, but it doesn't start to really feel like it is boosting until later in the powerband. Not sure if this is a good sign or bad. Pretty much what I expected I guess. But one thing I did notice is when rolling on the throttle with this setup, the tires would barely break loose in 2nd. This would indicate a loss of power for sure. Sigh. I hope the logs give me a good idea of what is going on. I may just put some sr16ve cams in there, raise the limiter to 8K or so, and put a .82 ar open housing on.

I did a leakdown test just before I changed the cams. Once I finally got the cylinders to seal right I got my numbers. 8, 8, 7, 8. So about 8% leakdown. This seems pretty good considering the big ring gaps. Before I built the motor I was seeing about 5-6% leakdown.

The next combo to try after I log this setup is: VE intake cam VET exhaust! And we will see how that performs.

I didn't really feel much difference in power when the exhaust cam switched though. Pretty much just like before. The note of the engine changed, but that was all I could tell from SOTP.

Took it out today. Spins through 2nd from a roll, except when the tires are really warm from doing it over and over lol.

The engine note seems to smooth out a lot when the exhaust cam switches. It actually gets quieter! And when the intake switches it sound amazing. The growl turns a lot of heads.

I say to hell with twin scroll. Slap a 1.02 A/R housing on it and go all out 20+ psi on 93 octane/110 race mixture. Enjoy the car as it shakes violently at 150+mph.

I'm officially scared of the Jackson Diamond car. :o

i'm with tekkie and I love fast cars