EFI experience and anyone tried a 6-speed or more automatic gearbox?

[alexsalvaris]

Hi all,

Was looking to see if anyone had any experience of swapping their carburettor set up to an EFI unit, and/or anyone tried to fit a "more than 4 speed" automatic transmission.

For reference, I have a 383 stroker engine with a Holley Street Avenger 670cfm carb. Should be good for c.450bhp and about 450 ft/lbs or 600Nm. I have not dyno tested however.

I have looked at the Edelbrock Pro-Flo 4 rather than the more popular Holley Sniper 2. The Edelbrock has a fuel injector in each runner of the intake manifold, which makes it a more true EFI unit than the Holley. I think! Anyone have experience of using either EFI system and what's your take on it? Not looking for more performance, just better and more linear power delivery throughout the rev range.

The transmission might be more challenging. I have a 700r4 and would like some more gears for better acceleration and keeping the engine in a better power range. I enjoy taking my C3 around a racing circuit. I have seen some builds using an automatic GM6L80 transmission. Anyone have experience with these or ZF 8 speeds?

Thanks,
Alex

 

[Roscobbc]

Quote
I have looked at the Edelbrock Pro-Flo 4 rather than the more popular Holley Sniper 2. The Edelbrock has a fuel injector in each runner of the intake manifold, which makes it a more true EFI unit than the Holley. I think! Anyone have experience of using either EFI system and what's your take on it? Not looking for more performance, just better and more linear power delivery throughout the rev range.
end quote
You are so right about multi-port injection. Why spend £1000 to perhaps £1500 for a fuel injection system like most that are effectively an electronic carb......this is what OEM car makers were fitting to American cars in the early/late 80's.
For perhaps double the cost of one of these above Edelbrocks Pro Flo 4 will give you individual port injection, a new inlet manifold, system specific distributor and dash mounted tablet to set it-up and display all sorts of parameters on.
All you need in addition is to fit a high pressure fuel pump in your tank (or a new tank with pump) or their fuel 'sump' in the engine bay.
Good deal I'd say..........but, my major concern would be if one ran-in to technical problems. All you will have is Edelbrocks dedicated on-line forum to ask questions and (hopefully) answers one can understand.
Take a few minutes to go on the forum and try to understand some of the silly problems (and non-conclusive OEM responses) that purchasers come-up with.......often bizarre. It seems to me that whilst it all appears relatively easy to install and set-up.....here in the UK we would almost be on our own........unless perhaps you have a third party install it. This (to me anyway) defeats the object of a reasonably priced product.
I have researched the FI issue for a number of years now (having had a earlier desire to install an old school 8 stack system to my stroker big block) and have come to the conclusion the old school methods (carbs) may not be as bad as we think. You won't get any additional power from fuel injection - better fueling and economy (relatively) perhaps, smoother running (perhaps)........but unless you travel many miles, fully understand how the systems work/or have a tame mechanic its going to cost you a comparatively huge sum of money for little return.
Multi speed transmissions - I think your current transmission probably has the ideal ratios plus a useful overdrive ratio to cover all type of use.
Modern 6, 8 and 10 speed transmissions whether manual or automatic are designed for todays computer controlled vehicles and maximum economy/minimal emission figures. Your 383 stroker engine has more than enough torque to obliviate the need for a multi ratio transmission and operate over a far wider rev band without the need for multiple ratio that a smaller capacity engine would need.
Most of the 6 speed aftermarket manual transmissions have gear ratios spaced once again for 'todays' economy/emissions orientated usage in computer controlled vehicles, and not always for performance use. You'll need to look very carefully at manufacturers spec's to find 'true' performance ratios on modern gearboxes.

 

[CaptainK]

I too have been wanting to put the Pro-Flo 4 setup on my 1968 327 - like you said, it has multi-port injection and so forth. Looked into it a lot.

The reality is though is that it costs a lot of money and I hardly drive my C3 that much. So as much as I would like a nice smooth setup of fuel injection and better economy, I can't really justify it as a priority for the mileage I do in my C3. I mean I've had the car 9 years and I've only done about 3.5 - 4k miles in it.

 

[Roscobbc]

And btw

I too have been wanting to put the Pro-Flo 4 setup on my 1968 327 - like you said, it has multi-port injection and so forth. Looked into it a lot.

The reality is though is that it costs a lot of money and I hardly drive my C3 that much. So as much as I would like a nice smooth setup of fuel injection and better economy, I can't really justify it as a priority for the mileage I do in my C3. I mean I've had the car 9 years and I've only done about 3.5 - 4k miles in it.

Capt' - I've had my '68 for 25 years and have done a similar mileage as you (max) and it ain't gonna increase too much in future.......so spending out perhaps £3.5K or more for FI just dosen't make any sense (and much the same with a 5 or 6 speed transmission)

 

[CaptainK]

And btw

Capt' - I've had my '68 for 25 years and have done a similar mileage as you (max) and it ain't gonna increase too much in future.......so spending out perhaps £3.5K or more for FI just dosen't make any sense (and much the same with a 5 or 6 speed transmission)

Wowzers, and I thought my mileage was bad in 9 years .

Out of interest, why did you go for the big powerful engine (over the original 427) and not drive it much?

As for 5 speed and FI and a 383 stroker - I'd love all in my C3, but I just can't financially justify any of it. I mean I battled with myself for a long time about getting electric headlights / wiper doors over the cost and the fact I pretty much never drive at night, and try to avoid driving in the rain . But then that outlay I ultimately justified because I wanted to fix my slow vacuum issues and slow wipers, and mostly I just wanted to challenge myself in fitting all that stuff to the car (I'm a noob when it comes to mechanics). I learnt a lot doing that.

 

[Roscobbc]

Wowzers, and I thought my mileage was bad in 9 years .

Out of interest, why did you go for the big powerful engine (over the original 427) and not drive it much?

The reason why Capt? - I have always loved the concept and fun of cars with excess cubic inches and loads of power without any for of electronic interaction. All these Supercars out there withan advertised zillion or so horse power........do you get to ever 'feel' all those zillions of supposed HP without electroic 'nannies' decided the tyres won't take it? - perhaps only at 'full chat' triple numbers speeds that you won't legally achieve on UK roads. My dream car would be an Edwardian open bodied race car with a huge capacity WW1 period aero engine.
Just love all the Ford 427, 428 and 429 powered cars of the 60's and early 70's.....and of course Mopar's equivalent and obviously GM's offerings.
50 or so years later so many aftermarket companies have honed and fine tuned all these engines significantly. For example the only item in my engine that is Chevy/GM is the engine block. Everything else is aftermarket......and arguably far better than GM's mass production items.
My goal was to equal or exceed the performance of GM's L88 power unit.....but in a street drivable way. Whereas the L88 engine is designed with a power band perhaps between 3500 - 7000 rpm mine is between 1800 and 6000 rpm and happy to cruise at 1400/1500 rpm with fuel consumption equal or better than a stock L36 427 (so 15/16 mpg on cruise)
As for not driving it much - other things (employment, family deaths, health issues etc etc) have simply 'got in the way' over the years. And of course we now have the spectre of Khan's London with its cycle routes, Uber drivers, many other road changes deliberately designed to catch-out the unweary and generate income for local authorities and Khan's TFL. I'll stop here or it'll turn in to a rant

 

[Forrest Gump]

Quote
I have looked at the Edelbrock Pro-Flo 4 rather than the more popular Holley Sniper 2. The Edelbrock has a fuel injector in each runner of the intake manifold, which makes it a more true EFI unit than the Holley. I think! Anyone have experience of using either EFI system and what's your take on it? Not looking for more performance, just better and more linear power delivery throughout the rev range.
end quote
You are so right about multi-port injection. Why spend £1000 to perhaps £1500 for a fuel injection system like most that are effectively an electronic carb......this is what OEM car makers were fitting to American cars in the early/late 80's.
For perhaps double the cost of one of these above Edelbrocks Pro Flo 4 will give you individual port injection, a new inlet manifold, system specific distributor and dash mounted tablet to set it-up and display all sorts of parameters on.
All you need in addition is to fit a high pressure fuel pump in your tank (or a new tank with pump) or their fuel 'sump' in the engine bay.
Good deal I'd say..........but, my major concern would be if one ran-in to technical problems. All you will have is Edelbrocks dedicated on-line forum to ask questions and (hopefully) answers one can understand.
Take a few minutes to go on the forum and try to understand some of the silly problems (and non-conclusive OEM responses) that purchasers come-up with.......often bizarre. It seems to me that whilst it all appears relatively easy to install and set-up.....here in the UK we would almost be on our own........unless perhaps you have a third party install it. This (to me anyway) defeats the object of a reasonably priced product.
I have researched the FI issue for a number of years now (having had a earlier desire to install an old school 8 stack system to my stroker big block) and have come to the conclusion the old school methods (carbs) may not be as bad as we think. You won't get any additional power from fuel injection - better fueling and economy (relatively) perhaps, smoother running (perhaps)........but unless you travel many miles, fully understand how the systems work/or have a tame mechanic its going to cost you a comparatively huge sum of money for little return.
Multi speed transmissions - I think your current transmission probably has the ideal ratios plus a useful overdrive ratio to cover all type of use.
Modern 6, 8 and 10 speed transmissions whether manual or automatic are designed for todays computer controlled vehicles and maximum economy/minimal emission figures. Your 383 stroker engine has more than enough torque to obliviate the need for a multi ratio transmission and operate over a far wider rev band without the need for multiple ratio that a smaller capacity engine would need.
Most of the 6 speed aftermarket manual transmissions have gear ratios spaced once again for 'todays' economy/emissions orientated usage in computer controlled vehicles, and not always for performance use. You'll need to look very carefully at manufacturers spec's to find 'true' performance ratios on modern gearboxes.

Hi Alex
Have you considered changing the differential ratio? Im not too sure what ratio you might have at the moment but I think the later C3s were geared more as cruisers regarding the final ratio.

Re the EFI, I know two people that fitted it and they are really happy with it. The background was that they were both totally fed up with trying to get their previous carburettor to work properly (probably something wrong with the carb in each case) so were faced with either buying a new carb or trying the EFI. Both did have fun and games trying to get the EFI to work properly and one of these guys is an electrician and very good with cars!
EFI isn’t going to be much better than a good carb - yours looks relatively new and is the right size.

 

[CaptainK]

I have always loved the concept and fun of cars with excess cubic inches and loads of power without any for of electronic interaction. All these Supercars out there withan advertised zillion or so horse power........do you get to ever 'feel' all those zillions of supposed HP without electroic 'nannies' decided the tyres won't take it? - perhaps only at 'full chat' triple numbers speeds that you won't legally achieve on UK roads. My dream car would be an Edwardian open bodied race car with a huge capacity WW1 period aero engine.

I very much agree, just don't have the finances for such fun. Closest I got was a 205 GTi with a tuned throttle bodied 306 GTi6 engine in it. Granted all electronic fuel injection etc, but still very fun having a car with much more power in it than it was designed for.

And yes, I love the old cars for that sense of speed at legal speeds. Like you said, fancy supercars are wasted most of the time as they are barely idling on public roads.

And oh yes, an aero engined car. Now we're talking