3.5" with a large cone (9" tall) cone air filter.

 

Yea I have the DXD Southbend Stage 5 six puck....rated to 825tq. Haven't had any slipping problems with this one.

And its not expensive as far as high power holding clutches go.

Tom

 

Strange, I love my OS Giken twin plates, except when I get stuck in heavy traffic (which is very rare), then it gets a little sloppy. But compared to some of the other single plate clutches like the RPS, that thing is like pushing against a concrete wall to engage. My OS Giken is like stock but much stronger. Very light and great engagement.

 

Mine is super grabby. It's easy to push but that's not my issue. The issue is that it grabs so hard it's almost impossible to take off smooth.

rich, i'm not sure what happened. I emailed hal last night.

 

wish we can can some input from hal on this thread. it might clear a few things up. jeff where u still using the borla exhaust when the tuning was done?

 

I'm here He did have exhaust on the car though I am uncertain of brand. I think swapping exhaust housing and dropping the exhaust would be a couple of great things to collect data on. As mentioned, due to complications during the day (wastegate spring swap, front main seal replacement, tires etc) we simply ran out of time. Jeff drove the car in and was unable to leave it, so I hope to see Jeff and the G35 again soon to dig in deeper.

 

+1 good motivation.

 

Yes, it is a borla system. With dual 2.25" pipes there is more surface area than a single 3" exhaust would yield so "technically" this shouldn't have been the issue.

Like hal said, my cursed car kept us with time constraints. I thought about dropping the exhaust off but after discussing it the backpressure was measured before the turbine housing which means the main restriction would be at the housing. Yes, maybe dropping the exhaust could have helped slightly but being that it's a well known decent flowing exhaust i think the restriction mostly lies at the housing. I can pull it off for some street testing when i get a chance. This semester is 33 credit hours at med school so i'm going to be pressed for time. It will be a slow progress.

Hopefully i can build up my funds and get my car back down there. I really like the atmosphere at IP and hal does great work. I think there is somethhing going on with my setup causing the problem with my driveability. It was perfect from the last tune until i changed out my DW 800 injectors for the HKS 1000cc injectors. Something tells me this might be the root of my problem.

I wish i was closer so this wouldn't be so hard for me to make trips over. It would also be easier to leave the car. I was in a bind this last weekend because i had no means to get back to indiana (home) to gather my stuff then head back to st louis for school.

I've been extremely sick and haven't driven the car except for today to get some logs for hal. Hopefully when i start feeling better i'll have more interest in moving ahead with this car. Right now thinking about it makes me even more sick to my stomach with the money i STILL have to invest to get this thing running right. it never ends.

 

Found some interesting ifo. here:
http://www.atpturbo.com/root/turbopi.../mkivsupra.htm

Just a comparison of T4 .70a/r and GT42 1.06a/r housings


18psi:



24psi:



Old "T" Turbo: T72 Compressor, .70 A/R Turbine housing
New "GT" Turbo: GT42 Compressor-94mm, 1.06 A/R Turbine housing

 

something else to be asked is.....are you running off the WG spring or a boost controller. Mine reacts pretty different when the BC is doing its thing VS just the spring.

Here's mine for example...the blue line is with BC doing its thang, the red is with BC off (don't worry about power numbers, obviously the more boost is more power....but look how much laggier it is with the BC off).

 

^^^Wouldn't that mean that you back pressure is high as soon as you get in to boost?

If you have to use the BC early on, your back pressure is hight and pushes the w/g open (from the plunger side) before boost reaches spring pressure. Hence having the BC work with the spring (agains back pressure) to keep it closed.

Just my line of thinking.

It is hard to judge though, not knowing what spring is in the w/g and what those boost levels are.

 

/\/\/\

I have no idea lol...I just know for most folks in general, the BC changes the boost curve vs the WG spring

Tom

 

Tom, boost vs rpm would better demonstrate what you are explaining.

A wastegate begins opening BEFORE you reach target boost, otherwise it would overshoot. It is not strictly open or closed, it moves between. With a boost controller targeting much higher boost, you can keep the wastegate CLOSED as it passes the wastegate spring pressure on it's way up to the higher target boost.

 

When using a turbo as small as a billet 67 on a 3.5 with variable cam timing, .81 is the smallest that I would use.

FWIW I just did a billet 6265 with a 1.0 a/r housing and our quick spool valve on a 3.0 supra and had 21 psi at 4000 and it made 730 rwhp, 735 RWTQ on E85.

 

Informative post, thank you very much. Some very good power for a 62mm turbo. Did you tune on pump as well?

 

do you have a dyno of that? i'm curious what spool would be like with the .96.

From your experiences Larry, would the .81 put down decent numbers? I'm not looking to shoot for the sky anymore, i just want some sick pumpgas numbers. Break 500 on the DD and i would be really happy to get to 550 on pumpgas.

 

finally some decent info!!! thanks hal and sp. now the big choice would be the .81 ar or .96.i think jeff and i have a common 550-600whp pump gas goal. from the experience you guys have with turbos, supras, vq's and many other vehicles. which a.r would be best for our application?

this is one of the most interesting threads i seen in a while.

 

It is starting to sound like (to me at least) that the .96 housing would be optimal for high HP goals. Although I think the .81 would be good for 500 or so. A true test would settle this.

Either way, I plan on test fitting the SP quick spool valve on my kit this winter. If it works well, a lucky person (with a built block) will get to test it out.

 

ok, i'm finally thinking my driveability issues are leaning towards my injectors.

In may, vortech, built engine, stage 0 cjm return fuel, dw 800 injectors. Hal had it tuned so it drove better than stock. So smooth.

I bought rich's hks 1000cc injectors because i was wanting more and needed them for my future turbo upgrade. When i got them in the car drove like crap. I assumed it was due to my lack of tuning ability so i didn't think much of it. So the car was driving crappy with everything else the same except the new injectors.

So is there a chance that the bucking and difficulty getting the vac map dialed in is the injectors? I don't really want to spend 120$ to send them off for cleaning if that's not the case.

 

also, if there is anything else that could be causing this someone chime in.

problem with my cams, heads, valves, etc? would those cause issues? what things should i start looking for?

I'm getting kinda burnt out on throwing more and more money into a car that i purchased good parts that "should" work. I can't see myself selling it but it's crossed my mind to throw my stock engine, clutch, fuel system back in the car and just drive it as a daily driver again. :/


also, if anyone has some injectors i could borrow to test i would appreciate it. Preferably a decent size. I have some old stock ones but i'm not sure those would be the best thing to test since they are more than likely worn out.