Inliners International Forums General Discussion Blown and Injected blown jimmy

I just bought a 4-71 gmc blower for a 302 gmc project I have. I know that I need to modify it, and I will be making my own intake for it. It will be awhile before I will have this 302 done. In my truck now is a 228 in good but stock shape, will a stock 228 live with low boost? And what are your thoughts on running a muncie or saginaw 4 speed trans with a blower? Some people say it is ok others say it is not. Or should I run an auto? But I like to bang gears so of it is safe to run a manual trans I will.
Thanks

I think a blower will work great with a 4 speed, you need a auto. with a turbo to load the turbo,
or you need a rich fuel curve and retarded timming to make heat in the turbine at the start.

Isn't loading it on a stall covertor the same as Loading it with a STD tranny.Your still raising the rpms before hammering the gas?? Many Imports are std and turboed. So i don't see the difference.??

a muncie will hold up fine. they came behind many cars in the 60's with 400+ ftlbs of torque and same hp. just limit the boost to 3-6 lbs. tom

We just installed a Muncy 4 speed in the Buick straight 8 last spring. We ran it at Maxton NC and on the salt flats, works great, we also are running a gmc 4-71 making 8 psi boost.

Twisted 6 - a converter stalls because in gear the engine is connected to the car and trying to move it, the resulting heat spools the turbo.
on a stick it's like the car is in neutral and freely revs and not much heat is generated so no spool.

so it is more of a heated issue rather the exhaust flow/pressure??
Ok another kinda silly question I have seen guys use NOS on the exh. of the turbo. (saying it helps spool) But don't or wouldn't cool the exh.?

But most imports i see are stick cars and i don't see or hear them laging so whats up with that?
Or is it something to do with the size?

With the little import engines you see them revving the **** outa them just so they don't have as bad of turbo lag.
You can hear a lot of the lag between shifts also when they are running a big turbo.

W/an auto trans it is so easy to build boost pressure (as long as you have some sorta stall) like @ least 2000 RPM (for a small turbo)off the launch.

On my Stock Syclone w/a auto trans,I just hold the brakes,give it some gas & watch the boost come up @ 2100 RPM.
I can get 3 lbs of boost or 20 lbs of boost, all depends how much throttle I give it, & this is being done @ the same RPM 2100.
Throttle position will give me what I want in terms of boost pressure.

W/a stick car,,, you cannot do that,,, hold your engine @ 2100 RPM & get a 20 psi launch,,,you have to rev the **** outta it,even then, it will lag a bit,& still not launch @ 20 psi.

Turbine housing size plays the biggest role on turbo lag, but there are other things also that will take part in "turbo lag"

MBHD

so it's the load more so Over rpm. Not free rpm/no load if i said that right.??

that is correct larry, a automatic allows you to open the trottle blades farther because of the slipping converter. more air thru motor= more turbine speed=more boost quicker. on mine you can't hold it back with the brakes, the tires will just boil. tom

Tom,,,,,

Tom have you heard about installing larger wheel cylinders for the back brakes?
I have to look up a part number.
I put them on my Syclone & I can hold 15 psi boost launch.
With the stock smaller size wheel cylinders, I could only hold 6-8 psi.

MBHD

I just read in this months Road & Track there are a couple of foreign cars that have electric motors on their turbos to keep the lag down. I don't have it handy but I believe Hondas is one.

Edit It's not Honda, it's Mazda. Mazda is starting (hasn't got a project number yet)work on a replacement for the RX-7 with a rotary. Mazda engineers are working full time on the RX-8 rotary to improve low end performance and efficiency (cleaner emissions)with the turbo. They added an electric motor to add boost on the low end and on the top end the turbo works as usual. This maybe continuing development from the RX-8 Hybrid seen at the 2003 Tokyo Motor Show. Honda is rumored to be working on something similar.

Larry

Twisted 6, flow and pressure (heat makes more pressure) is what spins the turbo.
The stick guys spin their turbos by making them super rich and retarding the timing like crazy so the fuel actually burns in the turbo.

Im trying to think of where I saw it but a Lexus with a turbo that wired up a rev limited to the clutch, so basically he could stay flat on the floor with the gas, put the clutch in and shift while the car hit the limited and popped and backfired keeping the turbo spooled. Hard on parts but effective.

Well I guess that now explains the NOS being used on the exhaust side of the turbos.

On my 4-71 I would like to keep it old school I was thinking of using a multi v-belt drive. What are your thoughts on this and how many belts should I use? If I use a cog belt would a 2" be wide enough?
Thanks

AWAG, I used a 2" wide Gilmer belt on a 454 Chev, only made 10 psi boost, it works fine. I later went to a 3" wide x 8mm belt when making 15 psi boost.