Best Fuel Injection System???
Thread Starter
Heel & Toe
Joined: Aug 2009
Posts: 18
Likes: 0
From: Pensacola FL
Best Fuel Injection System???
I have a 1979 Vette with a 383 stroker with a Demon 750 and about 425 hp. Its my daily driver and gets around 8-10 mpg and I would like to change to fuel injection to get more. What is the cheapest fuel injection system to go with? I was looking at going to a junk yard and getting the tpi off a late 80's Vette or Camaro, but i heard some say it would no suport that much hp? Is that true? If so, What system would? And what all do i need?
Thanks Will
Thanks Will
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
if i can get 18-19 mpg with a carb and 4.11 rear, u can too. Not just any carb. i use the 4165-6210
see my article http://community-2.webtv.net/MATTGRU/carb
see page 2 for carb info
.
But there is something wrong with your combo. Post details if u want help. There is nothing in your profile.
see my article http://community-2.webtv.net/MATTGRU/carb
see page 2 for carb info
.
But there is something wrong with your combo. Post details if u want help. There is nothing in your profile.
Last edited by Matt Gruber; Nov 23, 2009 at 09:11 AM.
Instructor
Joined: Jul 2005
Posts: 207
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From: Media PA
Racer
Joined: May 2006
Posts: 264
Likes: 0
From: Fort Myers, Fl / St. Paul, Mn
Matt, while I find your stuff on carbs and manifolds very interesting and will try your ideas on my car, my plan is to buy and install a Powerjection III when I get back home in January. I find, now that I have the interior and suspension nearly completed, that I spend most of my time screwing with carburetors. I hate those things. But they are fascinating - I still hate them!
When my 72 Vette and my 9 year old GMC pickup are both sitting in the driveway 9 times out of 10 I take the truck when going somewhere with a destination in mind. If I'm just going nowhere I take the Vette. My goal is to get the Vette to the point where I use it most of the time. Fuel injection would go a long way toward that goal.
When my 72 Vette and my 9 year old GMC pickup are both sitting in the driveway 9 times out of 10 I take the truck when going somewhere with a destination in mind. If I'm just going nowhere I take the Vette. My goal is to get the Vette to the point where I use it most of the time. Fuel injection would go a long way toward that goal.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
EFI is not going to turn an old car into a new one.
Any newer car is likely to be more reliable than a 30-40 yr old.
Nothing wrong with trying new stuff. EFI costs a lot and it stimulates the economy. They have a whole line of cams just for EFI. Plus, some require custom tuning that can cost $500. Or they don't need that, but can't handle a big cam. There is always something.
If u guys do EFI, whatever u do, avoid a single plane. It will have the same shortcomings as a carb
Any newer car is likely to be more reliable than a 30-40 yr old.
Nothing wrong with trying new stuff. EFI costs a lot and it stimulates the economy. They have a whole line of cams just for EFI. Plus, some require custom tuning that can cost $500. Or they don't need that, but can't handle a big cam. There is always something.
If u guys do EFI, whatever u do, avoid a single plane. It will have the same shortcomings as a carb
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Port EFI doesn't care about single or dual plane. Actually they run better on single planes. If you're considering EFI, pony up the extra $ and go port injection. The aftermarket EFI systems will work with big cams, it's just some of the factory boxes that don't like big cams.
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Racer
Joined: May 2006
Posts: 264
Likes: 0
From: Fort Myers, Fl / St. Paul, Mn
EFI is not going to turn an old car into a new one.
Any newer car is likely to be more reliable than a 30-40 yr old.
Nothing wrong with trying new stuff. EFI costs a lot and it stimulates the economy. They have a whole line of cams just for EFI. Plus, some require custom tuning that can cost $500. Or they don't need that, but can't handle a big cam. There is always something.
If u guys do EFI, whatever u do, avoid a single plane. It will have the same shortcomings as a carb
Any newer car is likely to be more reliable than a 30-40 yr old.
Nothing wrong with trying new stuff. EFI costs a lot and it stimulates the economy. They have a whole line of cams just for EFI. Plus, some require custom tuning that can cost $500. Or they don't need that, but can't handle a big cam. There is always something.
If u guys do EFI, whatever u do, avoid a single plane. It will have the same shortcomings as a carb
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
I'm looking at fuel injection as a replacement for outdated technology - the carburetor. If you are serious about making your car better, FI seems to be essential. I have no doubt that a good and patient carb guy could, given the time, tune a good carburetor to be almost as good as fuel injection - I'm just not that guy.
A brand new 4165 with like new lines, tank/filter will be as reliable as EFI. But it is old school and inexpensive. We will never pull out of this recession without some big spenders-like you!
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Single plane + big cam + EFI = fuel is injected into the runners at high pressure = good atomization.
Most factory EFI has issues with big cams as they see a low idle vacuum and dump way too much fuel (computer thinks the engine is under load). No such issue with an aftermarket computer. You can tune it any way you want. Most modern systems also let you increase the fuel table resolution for low vacuum.
With a big enough cam you still have fuel robbing from cylinder to cylinder even with port injection. But it will still run better than the same cam + carb. Direct injection will fix that issue but so far there are no direct injection retro-fit systems.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
But it costs like 10 TIMES that
a few years from now, when it dies, what then? tow to a chevy dealer? do they know those systems?
True they don't know carbs either. So who is gonna fix these new EFI's? What will the repair bill be? I just bitched and moaned that i had to pay $8.99 for a spare pump diaphram for my 4165. What do a set of spare injectors cost?
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
There is always going to be a huge debate on FI vs a carb and is it worth it. No it is not worth it from a dollar standpoint. You will never realize a savings unless you drive it a tremendous amount of miles. Most of us here do not drive it enough to justify it. That being said I switched over to FI last year and it cost a bundle. Was it worth it, you bet. Every time I fire the car up and it just starts and runs smoothly regardless of temperature or weather conditions it runs and runs hard. BTW I run a big cam and a single plane intake and it blows the carb setup away. My carb was tuned very good with a LM1 meter so the AF ratio was dead on. As for HP they make about the same peak HP but the area under the curve and the driveability of FI set up correctly will win every time. Nothing wrong with a good carb setup correctly but a properly setup FI system will be provide better economy and driveability every time. How many carbs do you see on new cars. I can take any new car stone cold or blazing hot and start it and drive it and never get a cough or sputter. Try that with a carb. 
Thread Starter
Heel & Toe
Joined: Aug 2009
Posts: 18
Likes: 0
From: Pensacola FL
Look guys. I didnt try to start a carb vs efi war. If my car was a weekend car, i would stay with the carb. Its not. Its my daily driver. I was asking what you think is the best bang for your buck efi. 7-9 miles to the gallon is not working. For under $1,000 i can get 15-17 mpg. Do the math. As much as i drive my car, it would pay for its self within 6-8 months. Thats why i want efi ... Would a stock TPI with larger fuel injectors support a 425 hp 383 stroker with a mild cam. Thats my question.
Thanks for all the info,
Will
Thanks for all the info,
Will
Le Mans Master
Joined: Nov 1999
Posts: 5,768
Likes: 3
From: San Diego CA
Look guys. I didnt try to start a carb vs efi war. If my car was a weekend car, i would stay with the carb. Its not. Its my daily driver. I was asking what you think is the best bang for your buck efi. 7-9 miles to the gallon is not working. For under $1,000 i can get 15-17 mpg. Do the math. As much as i drive my car, it would pay for its self within 6-8 months. Thats why i want efi ... Would a stock TPI with larger fuel injectors support a 425 hp 383 stroker with a mild cam. Thats my question.
Thanks for all the info,
Will
Thanks for all the info,
Will
you can support that with a TPI, but probably not an inexpensive stock steup.
Thread Starter
Heel & Toe
Joined: Aug 2009
Posts: 18
Likes: 0
From: Pensacola FL
If memory serves a STOCK TPI is limited in breathing capability. There are larger runners and intakes that can resolve this. but the Stock TPI isnt well regarded for hi-output excellent breathing motors.
you can support that with a TPI, but probably not an inexpensive stock steup.
you can support that with a TPI, but probably not an inexpensive stock steup.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
If memory serves a STOCK TPI is limited in breathing capability. There are larger runners and intakes that can resolve this. but the Stock TPI isnt well regarded for hi-output excellent breathing motors.
you can support that with a TPI, but probably not an inexpensive stock steup.
you can support that with a TPI, but probably not an inexpensive stock steup.
The TPI was really designed for a 305. It winded out at about 4500 rpm and it was done. The runners do not have enough airflow for a 383.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Lsx
best solution is a LS1 complete engine, then any chevy dealer can service it.
With no details available on your current engine which clearly has major problems, it is the safest route to turn an old car into a Daily Driver.
With no details available on your current engine which clearly has major problems, it is the safest route to turn an old car into a Daily Driver.