i have noticed there are a few guys around here planning turbo systems for their inlines, well, me too! i have a 59 chevy truck with a 235.

I have most of the system planned out, i have found out how to modify a carb for blow through, found the fuel pump and regulator i need, and i can sort out the plumbing issues.

what cams do you guys plan to run?
i saw clifford's has some performance cams, but they are ground on 110* lobe centers, isn't that a little close?

what pistons, rods and crank are you guys running?

lastly i have not completely decided on the turbo to use. i am leaning towards a t4 or similar. i have been meaning to buy corky bell's book so i can learn mor about compressor maps to help pick the right turbo.

try this site www.turbofast.com.au/TFmatch.html
you can find turbo sizes based on size, rpm, and boost pressure. you can also mess around with the power calculator.

buy the book. there is another and i'll get the name but it is written by hugh mcsomthin. i'm using stock replacement forged pistons in a 292. stock rods with new bolts and a reworked stock crank. camshaft is by comp and is 114 lc. dur @50 is 218 int and 212 exh. lift is 521 and 501. i am using a turbonetics 62-1 turbo. tom

Turbocharged by Hugh MacInnes

Check the publication date on the book before you buy. Also read Corky Bell's recent book on turbocharging.

What I'm working on right now is an EFI conversion for my car. I'm running a 230 inline 6 at the moment with plans to get my 250 going again and possibly a 292 sometime in the future. I working towards real multiport fuel injection. Fuel and spark management will be provided by megasquirt. I've already built the megasquirt unit and rounded up most of the sensors and done about 40% of the wiring for the car. Now I'm working on building a custom intake manifold at school (college) since I have a machine shop available to me some days. It's going really slow (I'm busy right now at school) but I'm hoping to be done the intake by january-february range. I modelled what I'm building in 3D using Inventor 7. All measurements are based on a 250 head I have and two injection systems off 2.8L v6 (manifolds, rails, injectors, plumbing).

I do have a long term plan for turbocharging so I'm keeping this in mind as I assemble the system. I'm going to build in enough capacity to be able to deliver 300HP or so worth of fuel under full boost conditions (10psi or so).

keep us informed greg. i am curious about the megasquirt system and have looked at their web site. i based my fuel injection system on a clifford 4 barrel intake. just added my injector bungs on a angle near the head flange. i am presently going to use a holley commander computer to operate it.

My project on the go right now is fixing up my 1981 Trans am and putting it on the road. She still needs quite a bit of work. Thing is, while I'm at school I don't have the stuff in place to work on it so the car stays at home about an hour away. And since I can't work on it directly I'm working on the EFI conversion in my basement instead.

The reason I'm saying this is because I could see it being a year or more (pretty easily) before I have a chance to really put the Megasquirt unit through it's paces. I'm going to post a good writeup when I'm done. But don't wait on me

Tom (tlowe) how has it worked just adding injectors to the stock intake? Or have you tried it yet? This was something I considered and frankly I'm not sure I made the right call as fabbing a manifold from scratch is proving to be quite a bit of work. Are you using one common fuel rail? About how much power do you have/expect from the turbonetics 62-1? I haven't really looked into the details of a turbo conversion yet (parts #s and such) but I know I'm headed there eventually.

As far as Megasquirt goes, just assembly and testing, it was pretty smooth. I've had the unit powered on my work bench and measuring on all sensors without any trouble. With the coming upgrade to spark control capabilities (around january) they're turning MS into a real powerful DIY system.

I am thinking of doing the same thing on my 302. Did you use 3 or 6 injectors? How did you hold them down? I thought of getting some threaded ones so I don't have to make an awkward hold down clamp since the manifold is curved. I am going to use a GM throttle body for the throttle only, including TPS, etc. Any other thoughts?

Thanks,

Ed Pruss
Longmont, CO

i mounted injector bungs on a 45 angle within 1/4" of the head flange. i did use 6 injectors 42lbs each. two per intake hole and mounted inline with one common fuel rail. i am also using a modern gm throttle body from the ls series vthings. mine is from a 5.3liter vortec. it is a big mono blade with tps and iac, and is cable operated. i have extras if anyone needs one. i do need to make an adapter to mount it to the intake at a 90 degree angle pointed toward the fender. if anyone needs i did make a very nice jig for clamping the intake to a mill to machine the injector bungs. i could provide that service to anyones 250/292 intake. my goal is 400 hp and lots of fun with a stick.tom

6 injectors at 42lbs?!? Jeez. That puts you at about enough capacity for ( (6*42)/0.55 ) 460 HP! Not so bad at all! Better to be too rich that too lean. Ed, I'm not sure what you're aiming for in the sense of power but even if you only had 3 of those size of injectors (42lbs) you'd probably still be good to about 230HP. Not sure about how well that would work (large port, weird flow, single injector.....might not be nice at idle). As far as throttle body it kinda depends what you're running as engine control. Megasquirt will run anything with a linear TPS is I remember right (might wanna double check). So it'll run different makes too. If you're just in the planning phase of EFI it might be useful to look into throttle body injection. Often those conversions are a lot easier and let you get started with EFI tuning ideas and such.

I'm using two throttle bodies because I figure I can get better air distribution that way. They're setup so that each runner can draw from each throttle body (but they're not evenly spaced between the runners) so the distribution should be pretty good. We're going to see I guess. I've made enough design assumptions I can't be sure how it'll all work until I actually try it. I figure I can't really make it worse than the stock manifold (although I'm not really sure just how good it is).

Hi fellas! A little new here to this board, but not new to EFI.

To Tlowe, if you try to run all six of those 42lb's in a 3 port style intake, you will never get that engine cleaned up at idle. You cannot get the pulse width down low enough with two per port to idle clean. With a lot of EFI systems you can set them up to run staqed injectors. In your case, you could run only three injectors until a predetermine MAP reading was met then turn on the other three injectors. This is very helpful with very small engine running very large turbo making extreme amounts of HP.

The Holley Commander 950 does not have provisions for this (unless it has been added in the last 6 months or so). What they do have is the ability to program the system as if it were running dual 4 barrel throttle body injectors. In this scenario, the back barrels of each 4 barrel T/B would not start injecting fuel until the throttle blades are starting to open (apparently the 4 barrel T/B's have progressive linkage).
I would think that you could utilize the dual 4 barrel T/B wiring format and alter it to work with two sets of three injectors. This would allow you to run three injectors at idle and utilize the additional three as RPM and Load come up.

I do recommend you talk to a Holley tech to make sure the injector drivers will be OK to run like this.

I would love to see some pics of your handy work.

RobT

Thanks, guys. The GMC 302 has a round intake port, so it is only really suitable for one injector of 50Lbs. I realize the Chevy has an oblong port shape. I would like to find a local guy who is using Megasquirt to look over his shoulder to see how well it works. My use is mainly for street use in a '46 GMC pickup(4WD) and a turbo someday.

Ed Pruss
Longmont, CO

Sorry Ed, I was thinking 250 series inline rather than 302. I don't know much about the 302 so I shouldn't talk.

I agree that those 42lb/hr injectors may not be too fun at idle. I've heard of lowering the fuel pressure at idle to compensate for overlarge injectors on an engine. Maybe if you setup up your regulator some how so that you dropped to 25psi or something low? You'd probably lose something as far as spray pattern and what but maybe it'd help with idle? Not sure.

I see a problem with running the stage injectors too. Since you've got an injector on each side of the port if you just shut one off you might hit some real distribute issues. Which is it's own headache.

i figured i would have some issues with fuel at idle but thats one of my lower concerns. just getting it all to run and work is my biggest goal. this is a big challenge but don't we all enjoy a good challenge occasionally? tom

It's all about priorities. Big things first, then the little stuff. The injectors I'm running may end up being too small but I'm going to run them anyways at first to get things going. Then we'll see from there.

Tom,

I'm running meagsquirt on a SBC for 2 years now and can help with configuring it.

I suggest that you consider running megasquirt using "dual table" s/w. What this does is operate only 1/2 the injectors until the boost come on and then the second set of injectors come in according to the 2nd VE table. Megasquirt can do this since it has 2 injector drivers, you need to wire injector driver "A" to injectors 1,3,5 and injector driver "B" to injectors 2,4,6. This works really well for a common intake runner like our 292's. You may need to turn the base fule pressure down to get a clean idle and then boost reference the regulator.

I'm planning on installing the injectors inline with the runners, centered vertically on the vertical wall of the manifold. My thoughts are that this will give the injector shot longer to atomise and I won't be spraying fuel on the manifold floor.

Comments welcomed

i ran a t3 cheetah g/n turbo suck thru set up on a 292 easily adapted....mad tq. 15 lbs boost 4400 rpm rev limit ..that turbo was a little small for the 292 but would work well with a 250 or smaller engine......some pics @www.suttonspeedshop.com.....under camaro project