Need EFI manifold recommendation...
Thread Starter
Racer
Joined: Jul 2004
Posts: 276
Likes: 0
Need EFI manifold recommendation...
Hi all,
I have a stock L-48 (76) and I'm starting to plan out my EFI conversion.
I have the fuel injection controller already (www.megasquirt.info).
What I'm trying to figure out at this point is whether I should buy an EFI intake (with injector bungs in it) or try to get my stock intake modified (I've never taken it off, it's a dual plane).
This car is my daily driver, so any changes I make (manifold swap, etc) have to work with my stock Q-jet for now.
I don't have a welder, so if I modified my stock manifold I'd have to farm that job out.
I'm leaning at this point to getting an aftermarket TPI manifold (holley stealth ram or similar). What are my options to fit under a stock 76 hood?
If I went the route with the stock manifold, I could just gut an old Qjet and make it the throttle body.
I have a stock L-48 (76) and I'm starting to plan out my EFI conversion.
I have the fuel injection controller already (www.megasquirt.info).
What I'm trying to figure out at this point is whether I should buy an EFI intake (with injector bungs in it) or try to get my stock intake modified (I've never taken it off, it's a dual plane).
This car is my daily driver, so any changes I make (manifold swap, etc) have to work with my stock Q-jet for now.
I don't have a welder, so if I modified my stock manifold I'd have to farm that job out.
I'm leaning at this point to getting an aftermarket TPI manifold (holley stealth ram or similar). What are my options to fit under a stock 76 hood?
If I went the route with the stock manifold, I could just gut an old Qjet and make it the throttle body.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I faced similar prolems when engineering the DPFI system I had on my Pontiac 455, some 13 years ago...and still have the mechanics of the setup....i'ts a nitemare...you are better off by FAR to get an allready machined intake/fuel rail setup with central t-body on it....it's a single plane.....
I had NO such parts available for the Poncho engine way back when, today they are more or less 'available' but way tooooo expensive....not worth it....
the angles of the injectors are important, and they don't intersect well with dual plane manifolds...machining is a bitch and expensive, and then there is the welding, then the fuel rail...you would cry if you saw the setup on the Pontiac....
GENE
I had NO such parts available for the Poncho engine way back when, today they are more or less 'available' but way tooooo expensive....not worth it....
the angles of the injectors are important, and they don't intersect well with dual plane manifolds...machining is a bitch and expensive, and then there is the welding, then the fuel rail...you would cry if you saw the setup on the Pontiac....
GENE
Team Owner
Joined: Apr 2002
Posts: 62,198
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From: All humans are vermin in the eyes of Guru VA
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Burning Brakes
Joined: Sep 2002
Posts: 1,179
Likes: 3
From: SF East Bay CA
Got mine from Ken at www.firstinjections.com
I am also running a F.A.S.T. ECU with wideband. The manifold/plenum set up works great. I had to add a serp system so I could run the twin air intakes (aftermarket C5 intake)... Good Luck on your conversion.
I am also running a F.A.S.T. ECU with wideband. The manifold/plenum set up works great. I had to add a serp system so I could run the twin air intakes (aftermarket C5 intake)... Good Luck on your conversion.
Safety Car
Joined: Jul 2001
Posts: 3,921
Likes: 2
From: York PA
I like my TPIS miniram, although it's a little big for my current setup. I think (but not positive) that Holley stealth ram should fit under the stock hood. If you are going to keep you motor stock, look at a GM TPI setup, or one of the modified versions of this. Accel makes modified components for the TPI and various EFI manifolds.
Pro
Joined: Apr 2005
Posts: 591
Likes: 7
From: Batavia IL
well another option is to modify an lt1 intake for your heads. there are also people who keep the egr by plumbing it away from the distributor. I think you can pass with out the egr though. My carb'ed vette passed chicago emissions with out egr and they are very strict. here is a site that sells lt1 intakes already ready to bolt on. LT1intake.com
Burning Brakes
Joined: Jul 2000
Posts: 1,162
Likes: 2
From: Beaverton, OR
I don't have any advice on which intake you should go with that hasn't already been mentioned. . . I am however interested in your opinion of the megasquirt setup. I have a fuel injection system made by HI-Rel (now owned by Holley) that an uncle gave me. Unfortunately the computer with it was for a boat, so I need to do something different. Holley wanted something like $900+ for their setup. . . A month or so ago a friend told me about the megasquirt setup, though he had no experience with it. Seems like for the price (less than $200) it can't be beat.
You have any pictures of what you got? If you don't mind my asking, what did you pay for everything also?
Regards,
-dath
You have any pictures of what you got? If you don't mind my asking, what did you pay for everything also?
Regards,
-dath
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Safety Car
Joined: Jul 2001
Posts: 3,921
Likes: 2
From: York PA
Originally Posted by DonBecker
I think my biggest problem right now is finding something with an EGR on it. Arizona emissions are pretty tough.
Thread Starter
Racer
Joined: Jul 2004
Posts: 276
Likes: 0
Talked to Edelbrock today, they recommend their EFI intake for converting 87 and up Chevy trucks from TBI to TPI.
Hate to lose the gutted Qjet concept, but the throttlebody will flow 550 cfm, which is plenty for my anemic L-48.
dath, check out: http://www.rs-autosport.com/
that's where I bought my controller and stim. I'll be buying a bunch of other stuff from there, Rodney is a good guy.
Read up on megasquirt @: www.megasquirt.info
They also have forums. There is a ton of EFI info there, and you don't have to spend an arm and a leg to fuel inject your car.
Let me know if you have any questions.
Thanks again for all the help guys!
Hate to lose the gutted Qjet concept, but the throttlebody will flow 550 cfm, which is plenty for my anemic L-48.
dath, check out: http://www.rs-autosport.com/
that's where I bought my controller and stim. I'll be buying a bunch of other stuff from there, Rodney is a good guy.
Read up on megasquirt @: www.megasquirt.info
They also have forums. There is a ton of EFI info there, and you don't have to spend an arm and a leg to fuel inject your car.
Let me know if you have any questions.
Thanks again for all the help guys!
Thread Starter
Racer
Joined: Jul 2004
Posts: 276
Likes: 0
Eventually yes, but I feel like it needs a complete overhaul, and the EFI conversion won't be stressing anything in the engine anytime soon.
I haven't really decided whether to get a new engine or just mothball the vette while I rebuild the old block.
The EFI is fun stuff.
I haven't really decided whether to get a new engine or just mothball the vette while I rebuild the old block.
The EFI is fun stuff.
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
I wouldn't go with a wet designed manifold. Seems like you lose too much that could be gains since your going EFI. Like just adding throttle body. You can gain more.
I kind of doubt exact placement of the injectors since the manifold modified types have them sticking straight up and they are spoda point at the intake. On my BB there is no way to point an injector at the intake valve that I can see since it would have to be in the duct itself.
I'm up **** creek and cheap besides so going to try building my own intake. Long runners for low end with sliding throttle plates for high end short runners.
You have the advantage of buying off the shelf but this also restricts you to what is available.
I kind of doubt exact placement of the injectors since the manifold modified types have them sticking straight up and they are spoda point at the intake. On my BB there is no way to point an injector at the intake valve that I can see since it would have to be in the duct itself.
I'm up **** creek and cheap besides so going to try building my own intake. Long runners for low end with sliding throttle plates for high end short runners.
You have the advantage of buying off the shelf but this also restricts you to what is available.
Thread Starter
Racer
Joined: Jul 2004
Posts: 276
Likes: 0
Can anyone point me to where I can find out about which GM stock TPI manifolds will bolt right onto my stock 350?
Even a parts interchange would help.
Are any of the stock tpi's gonna allow me to keep my stock large cap HEI?
Even a parts interchange would help.
Are any of the stock tpi's gonna allow me to keep my stock large cap HEI?
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Originally Posted by DonBecker
Eventually yes, but I feel like it needs a complete overhaul, and the EFI conversion won't be stressing anything in the engine anytime soon.
I haven't really decided whether to get a new engine or just mothball the vette while I rebuild the old block.
The EFI is fun stuff.
I haven't really decided whether to get a new engine or just mothball the vette while I rebuild the old block.
The EFI is fun stuff.
plan ahead so you don't waste $$$$
Racer
Joined: Jun 2004
Posts: 322
Likes: 0
From: The Dirty, Dirty South
Originally Posted by DonBecker
Can anyone point me to where I can find out about which GM stock TPI manifolds will bolt right onto my stock 350?
Even a parts interchange would help.
Are any of the stock tpi's gonna allow me to keep my stock large cap HEI?
Even a parts interchange would help.
Are any of the stock tpi's gonna allow me to keep my stock large cap HEI?
Any of the L98 manifolds off a Vette will work, and they have the added bonus of routing the fuel lines on the passenger side as opposed to the f-body manfolds that route the lines on the driver's side. The main difference is the middle two bolt holes on any f-body manifold after 87, which have the 72 degree angle. They can be altered to the 90 degrees used on the earlier heads, though. I got a manifold from a 91 tpi Trans Am, I don't forsee any insurmountable problems getting it to fit. As far as the HEI, once again, early C4's had a large cap dist. that was computer controlled (85,86 I think). Some of the vendors may have them, or you can probably get one at Napa...
