What I have learned so far from my junkyard dog turbo project.. feel free to add!

Figure on twice the cost you started with, then add some more

Add fuel, subtract timing

You can do it yourself, but do some research!

Make sure how to adjust the BOV so it doesn't open at 4 psi instead of 12

Stuff gets kinda hot under there!

Rear tires are expensive

trying to launch in 1st and hitting the rev limiter before it moves is cool

...but not as cool as launching in second and spinning the tires so hard you have to get out before the ditch comes up

cams with extra exhaust duration let the boost blow thru

mild steel works fine for headers, just get it coated if you want it to last

Turbo Supras give you funny looks when they finally catch up after a 50 mph punch

The Forced Induction Forum Rocks!

LT1's REALLY like the boost!!!!



Now to get it broke in with all the new parts and try out the 100 shot!!


Film at eleven!

 

This touches on a point I've tried making in the past. Vizard says that supercharger/turbo cams need to open the exhaust valve late because boosted engines retain cylinder pressure later in the power stroke. Opening the exhaust valve later gets more work out of the high pressure gas. This points towards less exhaust duration and goes against most accepted logic about dual pattern cams and boost.

How did you discover this? Dyno, track, or neither? What were the results?

Mike

 

stuff gets really, really, hot under the hood.

 

Combination of dyno results and talking with the techs at Comp cams, Crane and Combination Motorsports. All recommend reverse split cams for a turbo app.

My dyno numbers were representitave of 6-7 psi, not the 12 psi I was seeing at the intake. I also loose some RWHP compared to a late model, due to my 3500 stall, T350 and 31 x 16.5 sticky tires, probably around 30-50 hp compared to a 6 speed car.

So 405 RWHP at 6200 rpm was "fair" for 6-7 psi thru intercoolers on a typical 95+ Houston day. But not for 12 psi. Blame it on the Hot Cam and the drivetrain. But the torque peak was right around 3200-3400 and over 500 ft/lbs up to 4500, so something is working ok!

 

I had the same dyno experience. Vigilante "0 pump" converter, which is rated at 2800, but stalls closer to 4000 behind a blown stroker. I "only" dyno 550 rwhp but run 10.40's in a full weight street car.

What are your old versus new cam spec's?

Mike

 

Twice the cost... I figured around $4K and have spent in that neighborhood, but I did buy some stuff and had to sell it because it wouldn't work (like before I finally bit the bullet and built headers, vs. trying to get some to work) The little things added up QUICK!

How do you adjust the BOV? There should be 2 ports on it and when under boost there is the same pressure on both sides of the BOV, and the spring should keep it shut... Thats how mine works, but the big *** Tial BOV's only use 1 port.

My .68 A/R exhuast housings make for late spool, which I kinda like. It starts to make boost after 3K in first and then hits hard! Makes my launching a little easier. Plus once it's spooled in first, it jumps right back when shifting, no loss.

I do love this Forum as well

What in Gods name do you need N2O for Thats what they make boost controllers for

another point to add... I hate freeking Exhaust manifold gaskets. I blew out my Felpro 1406's the first day
I have the Felpro stock gaskets that bolt to the outside holes on the first and last cylinders, They have a little more beef on the ends, which is where they always blow out on me. I will have to try some stock ones from GM for the LT1's.

Bill

 

Cam specs... had a LT4 Hot Cam, went back to the stock LT1 cam with 1.6 RR for now. The lowest boost I can get with my non-adjustable wastegates is 12 psi, so that will be a bit high on pump gas with a dedicated turbo grind. And the budget can't handle the alchohol inj. and new cam right now!

My BOV is a Type R, which has a screw and nut that adjusts spring pressure. It only uses one hose, referenced to manifold boost, and a spring preloaded pop off valve. Supposed to be good to 14 psi or so cranked all the way down, I had mine almost all the way backed off at the start. Now it is almost all the way tight and works MUCH better!

Why NOS? because I can spray the 100 shot on pump gas!

 

If you have a Greddy Type-R BOV then you have it plumbed wrong. I had one of these back in the day on my first turbo setup and it most definately has two ports. The one you have hooked up is probably on the top and you have that running to the intake manifold. Look on the cast part of the BOV, there is another port that needs to be ported to the turbo discharge (anywhere after the turbo and before the throttlebody) The reason I know you have it hooked up wrong is because that is exactly the way I had it, before I looked more carefully at the instructions Hook up that second port and try that. You will have no more problems with it lifting. The spring is supposed to control the sound of the BOV releasing. The way you have it now it probably doesn't sound like much when you get off the throttle. With both lines connected it will sound AWESOME, and like it should! Let me know how it goes!

Bill

 

I dug up an old pic of the BOV on my webpage: http://www.bytehead.com/~dunk/turbo.html
It's like the 4th to last pic on the page. This is how I had it hooked up wrong, and you can clearly see the other port that needs to be attached to the turbo discharge. I usually just weld in a bung right near the BOV and route a line with two hose barbs, and problem solved.

 

hmmm everything I have, and according to the imports crowd, it only has one line hooked up. It clearly states to leave the second port open, even tho I see threads in there.

It has no problem venting and I can hear it fine, but I may have to try it y'alls way just to see!

 

That is exactly how mine is plumbed, with the bottom port open.
Interesting.

Guess I will have to pull the intake pipe and tap me another hole (on the bottom, out of sight!)

I can hear mine vent, everytime I let off the throttle, but it isn't all that loud. I've been looking for a horn that will thread in, but I'll give your idea a shot and see what happens.

thanks!

 

It will be loud with the bottom hooked up

 

If you want loud, get a Type XS RFL. Those things are extremely loud from what I remember from my DSM days. No tone, but it sounds impressive.

 

I wasn't so much looking for loud.. most of the import BOV's are really small diameter, like 1" or so

The Type R was about the biggest one I saw, and I have it on the bottom of a 3-1/2" inlet pipe, so I wanted to be able to vent as much pressure as I could.

Guess we'll see how loud it is when I hook up the second port.

 

Texlurch, what kinda fittings did you use on the fuel regulator? It doesn't look like you used the black -an fittings w/ o-rings that aeromotive sells. Can you put a normal -an fitting in there with their o-ring?