Bench Race this w/me ...

[Bamfster]

Re: Bench Race this w/me ...

Some more food for thought on the TBI....

Procharger sell superchargers for the gm tbi trucks that run (i think) up to nine pounds of boost, and they somehow boost reference the regulator. If the tbi will work with a procharger, why not with a turbo ... boost is boost right?

After searching the net high and low, there are hundreds of opinions on turbo sizing, single vs twins etc. I'm kinda getting lost with the info overload about different trims, AR numbers etc. I know the CC article outlined what they did with the T3/T4 hybrids, but why those? Why not a single?...But what size? I want to plan/build/tune this thing by myself, not follow an article and replicate something ....

Someone posted up a link for turbo sizing etc a long time ago here, but for the life of me, I can't find it. I think it was Dan Stokes who posted it, anyone else remember?

[IRONHEAD]

Re: Bench Race this w/me ...

it's a 2 bolt block, I'd stud the mains and heads and new rod bolts..
you could score a 305 vortec top end from a van cheap enough for better heads and a plumed intake
or a 350 vortex top end..
yes you can shove the air through the worst heads, but it'll also heat the air more,, and pump gas..
I was at 10 junkyards this week end.. not one turbo to be found... even the saab's and volvos where picked clean..
there was one powerstoke, but it was toasted, and no idea if the parts are anygood after that

[Bamfster]

Re: Bench Race this w/me ...

The whole point of this is low $$$, if I'm gonna go to all that trouble, I'll just build the 350 I found in the street .....

Here is the victim, I pulled it out from under the bench this morning:

[Blazerteam]

Re: Bench Race this w/me ...

Just do it..we are always finding new parts and better heads carbs etc,and end up doing nothing but want stuff.

Wrench-drive-break ;D

[TC]

Re: Bench Race this w/me ...

According to DG when running twin turbo's you treat the engine like two 4 bangers. So you'd want to size the turbo's to the amount of HP you think four cylinders of the motor would make. So lets say you want to make 700hp, then basically running two turbo's that are rated to 350hp would get you there/close. Benefit's are the twins will spool up quicker than a single and running the exhaust is easier since you don't have to cross one sides exhaust to the other side where room might not be there.

As for turbo's, if the motor is a about 300ci, then a couple of T3/T4's would probably get you to that 6-700hp mark. If your going to do this with a 350, then a couple of T4's would definitely do the job and would probably serve you well at multiple power levels.

Here's a T4 that would do the job and some.

http://cgi.ebay.com/ebaymotors/GODSPEED-Gt45-T4-1-00-Trim-Turbo-600HP-S10-SILVERADO-V8-_W0QQcmdZViewItemQQhashZitem27b3776188QQitemZ170514669960QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[Bamfster]

Re: Bench Race this w/me ...

6-700 hp .... i'd be happy with a streetable 300 corrected for 9000' D/A. So seeing as this engine will only be 307 cid, and lower HP, are there smaller (read cheaper) turbos that will get me there?

So what about "mm" sizes, what do the "AR" #'s? mean....

[BobStuart]

Re: Bench Race this w/me ...

A pair of 60/.63's from 85-86 Turbocoupes will get you there and then some. The 60/.48's from the automatics would work good too. http://toohighpsi.com/ Scroll down to the Blue bomb. The engine is still running great after 10 years, although sadly the Mustang has succumbed to cancer. It's heart is being transplanted into an 88 T-bird.

[terry russell]

Re: Bench Race this w/me ...

I think it should run in the high 13s + 17/19 mpg.Build it
terry

[IRONHEAD]

Re: Bench Race this w/me ...

I'd think on a daily driver sizing is everything..
to big.. boost comes on to late in the rpm for a mild build with low budget valvetrain
to small.. great power off tip in of throttle at the cost of boost at cruise.. killing mph..
as the boost make the small c.i.d. act bigger than it is.. and that requires more fuel..
so, I'd think sizing will require knowing what rpm it will run at, at hyway cruise(mph)
to have a balance of power and mpg.. untill you drop hammer.. then mpg goes out the window..

[dieselgeek]

Re: Bench Race this w/me ...

how did I miss this thread??

My thoughts:

Skip TBI for turbocharging. Fuel distribution issues, etc. Might as well go carb with that - but remember, on the street you need "part throttle" work too. When cruising up and down gentle hills, you will see a little boost a part throttle - I have no idea (nore much confidence) how a carb setup handles load that does not consistently vary with throttle opening/vacuum. You'll run out of injector really fast too. THe fuel pressure would have to be boost referenced, which is hard to do with an internal regulator in the TBI.

I'd figure out a port EFI setup. It's not going to cost that much more to do, and will be worthwhile when you're driving on the street - looking for economy, smooth running, etc. TBIs have distribution issues, worse than carburetors (sometimes, by far).

I think the 307 is fine. I'm not an expert at turbo sizing, but I can tell you for sure - don't be afraid of a single because it's 100% internet myth that "twins spool faster" - with twins, you cut everything in half so it's no different than with all 8 cylinders feeding a single. With the single, you end up needing a crossover pipe and will likely have more hot piping under the hood; but you only have to spend the money on a single BOV and wastegate (look into an external gate regardless of which junk turbo you use, IMO). With twins, gates and BOVs add significant bucks to the cost.

Some guys here - with a LOT more experience than me - will say you ca get away without a blowoff valve. I prefer to run one, but you could save some bucks perhaps.

It's possible that the internal gating on some turbos will work for you - add that to your list of things to check out.

EFI is no more difficult to tune the first time on a turbo engine than on a naturally aspirated one - no worries there.


I wouldn't fear the 307 or a crappy set of heads, either. Be more concerned with a good installation for reliability. Tom Hogshead from KC - the cop who always runs drag week - would have great advice for you. His builds are always inexpensive, but he learned a lot about heat management, longevity of the hot and cold plumbing, reliability, etc. He switched from carbs to a low buck Holley 950 if I am not mistaken. Really cool guy, does anyone here know how to get in touch with him? ksj1 maybe?

-Scott

[milner351]

Re: Bench Race this w/me ...

this is gonna be SWEET!

(so is that diesel olds block set up!)


Aaron just sent me a CL link to a $100 powerstroke turbo - want me to grab it for you or are you going to run two smaller ones?

[Bamfster]

Re: Bench Race this w/me ...

I appreciate the offer John but I'm a ways from actually "building" this. I've been researching the F/I stuff the last few days and .... well, I need to learn a bit before I head that route.

The turbo stuff (sizing etc) is starting to make sense to me. I'm not one to buy something sight unseen, I need to touch/fondle/look at it before I actually get it.

Decisions decisions .....

[Bamfster]

Re: Bench Race this w/me ...

So let me throw this out there....

What about an intake/injection setup from one of the ramjet 350 engines? Can it be made to work with a Mega Squirt controller? Hmmmm .....

[dieselgeek]

Re: Bench Race this w/me ...

What about an intake/injection setup from one of the ramjet 350 engines? Can it be made to work with a Mega Squirt controller?

totally will work. now you're thinking!

[TC]

Re: Bench Race this w/me ...

I'd think on a daily driver sizing is everything..
to big.. boost comes on to late in the rpm for a mild build with low budget valvetrain
to small.. great power off tip in of throttle at the cost of boost at cruise.. killing mph..
as the boost make the small c.i.d. act bigger than it is.. and that requires more fuel..
so, I'd think sizing will require knowing what rpm it will run at, at hyway cruise(mph)
to have a balance of power and mpg.. untill you drop hammer.. then mpg goes out the window..

Being the motor is a 307and he wants it to be a street car, I think a pair of T3/T4 hybrids would work real good.

Look on Ebay there are TONS of turbo kits for SBC's. Prices range from 1000-1500 bucks.

And took through the different kits, some have more pieces than the others and some come with an intercooler and some don't.