Yea, in this application I would definitely agree. Spool time isn't going to be an issue for this exhaust housing on a 4.4L, your not trying to extract every last bit of power out of this like you would in a race application, and you aren't going to be treating the turbo so harshly as to warrant the BB setup. Now if you decide in the future to drag this thing, setup an anti-lag / two-step launch parameter, or prefer to remove your BOV and subject the compressor to those strains...well then you will want the BB.

But since you are journal bearing I would be extremely careful about putting an oil restictor in. I wonder what the Z06 TT guys use for oil return pumps...

 

I'm not going to be restricting it without say-so from Precision. No smoke on several WOT runs today. The pump I'm using came highly recommended and was really expensive so I'm going to be pissed if it doesn't work out. I've seen a lot of people use pumps not rated for hot oil and heard a lot of stories about them failing in 6 months or a year. I spent the big dollar to get a pump that would last.

I'd like to get some kind of an anti-lag set up but I don't think I can do it with HPTuners.

 

Email Bill and Chris and see if they can help you out.

 

Just an update on the smoking/oiling issue...it's gone. I'm just tuning right now. I've maxed the MAF sensor in Hz and lbs/min so I'm working on a solution for that. I'll probably be testing my new tune on Sunday and if it works out I can turn the boost up past the 11psi I've got now.

 

Good Luck Tim!!

 

Another update: I got my scaled tune to work and I turned the boost up to 13psi yesterday. My stock injectors are at 100% now even though they are boost referenced (fuel pressure rises 1:1 with boost so you don't loose injector flow fighting boost pressure). 48lb injectors should be good for 600rwhp and I know I'm not making that yet so I don't know why they are maxed. Maybe fuel pump. I've got too much to do this week so it will be some time next week before I can get it on the dyno to check fuel pressure during a pull. Removing the tank to upgrade the fuel pump is a huge pain in the ass so I hope it's not the pump. I don't really see what else it could be though.

 

$175 get them made in to 60's

 

I'd have that done right away if that was the problem. 48s should be plenty big. People have made over 600 at the tires with 48s.

 

I changed my injectors to 58s.

 

Dyno time is scheduled for after work on Monday. We should be able to figure out what is going on with the fuel situation. We are also going to look into why it spools slow. I'm not getting full boost till 3800 rpm.

 

No updates yet. Heat and scheduling have delayed dyno time. I'm hoping to get it done this week but I'm not in that big of a hurry for some reason. I've been busy building headers on a 72 Blazer/6.0 LS swap and it is taking all my time. I just got the last tube tacked so I just have to weld them up now.

 

Got it on the dyno last night.

464rwhp in 3rd gear at 13psi. We tried a 4th gear pull but had to abort due to dropping fuel pressure. Pressure dropped on the 3rd gear pull too, but I had the car tuned around it so the AFR stayed at target till the end. No more power can be made until I upgrade the fuel pump.

I have the turbo pull laid over the last supercharger pull I did. Torque curves are not on there because I forgot to set up the rpm input. Pull only goes from 3000 to 6200 or so because I knew I didn't have enough fuel pump to run it to 7000rpm+ like I usually do. You can really see the power gains once it spools and the losses before that. I'm going to swap the exhaust housing to the next size smaller to help with that.

 

Great work TimmyC.. looks like you only have a few more things to work out before it's complete. What are your boost level goals after you upgrade the fuel system? Kinda hard for me to read the graph numbers but it looks like a nice improvement so far. I'm anxiously waiting to see higher boost numbers to see if there is an obvious sticking point for our engine setup (minus turbo or supercharger). If anyone is going to find it you will with your setup.

 

I'm going to turn the boost up till it doesn't make any more power. I'm only running 8-9 degrees of timing right now and it's at the edge of spark knock. I still have the stock plugs in it so that might be part of the reason for that. I'm going to go a heat range or two colder and see what happens. After I max out pump gas I'll put some race gas in it and go again. Then I'll probably try e85. I'd like to see 600rwhp at least once on the dyno.

 

update?

 

Trans is out for rebuild/upgrade. Updates will follow when it's done.

 

How much street time does the car see? Any concerns with driving in rain due to the filter being so close to the ground?

 

It is my DD. I got a pre-filter for it last week so we'll see what happens next time it rains. I drove it a half hour in a major downpour right after the turbo install and it did suck up a little water. I took the intercooler out thinking it had a bunch of water in it but only a couple ounces came out. With the filter sock I think I'll be good. The filter is not in a direct line with tire spray.

 

Trans is back in the car. I won't be able to finish it up till Thursday though. Then I have a lot of work to do on the tune to readjust for fuel pressure that is not dropping after 10psi boost. I wired in a boost-a-pump for that.

 

if this goes well, I am willing to give this a try! lol...

 

Finally got the car running tonight. I ran into a snag with the turbo oil feed line last night and had to wait till today to get a replacement. I did a little tuning tonight but it was dark so I couldn't go too fast. The .68 turbine housing helped a bunch on the lag problem. The boost doesn't come on all at once anymore. It builds more like a supercharger from 2700rpm with full boost at 3700. I'll do some more tuning this weekend and next week then put it back on the dyno and see if I can turn the boost up.

 

Thanks for the Update and good luck!

 

Went back to the dyno today with a boost-a-pump wired in and working. We played around with ignition and cam timing and made some good gains. The biggest gains came from dropping the exhaust post-downpipe (39rwhp) and replacing the air filter with a 45 degree coupler and a bellmouth (24rwhp on top of the 39 from the exhaust). Totals on the day were 502rwhp/517rwtq in full street trim, 537rwhp/546rwtq open downpipe, and 563rwhp/568rwtq open downpipe, no air filter.

Max boost is 15psi on the 563 run falling to 13.5psi by the end of the run. I turned the boost controller up but boost did not change. I am pretty sure the waste gate is blowing open from exhaust back pressure. I should be able to turn the boost up if I put a stiffer spring in the gate. There's only a 6lb spring in there right now.

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At the next dyno session we'll be able to turn the boost up and mix in some race gas. 600rwhp should be easy. I'd like 550rwhp in street trim.


AFR is 11.5 on the street trim run and gets leaner on the other two. 11.8 and 12.2 on those. The AFR stuff on the graph isn't right. I was going by the wideband in my car and didn't worry about the dyno gauge.

 

WOW... congrats :shocked:. So after all the tuning and mods adjustments what do you think the biggest restriction is for people keeping the supercharger? Do you think headers are worth it or is it simply the supercharger arrangement? I feel the intercooler is a big air restriction with the stock car. You should consider fabricating a replacement and selling to everyone on the forum . I can't imagine how your car drives with that power. Good thing you upgraded the transmission. Great work.

 

Thanks. I've gone over my thoughts on this before but here they are again quickly. I think headers with no cats will be worth 20-25rwhp. The intercooler setup blows but there is almost no room to build a better one and have it fit under the hood.

 

That's impressive torque too...I would expect it to run better times than your average 500rwhp turbo car (weight not withstanding of course).