Offshoreonly.com - EFI, Edelbrock vs Holley vs FAST vs Accel

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Quote:

Originally Posted by bcarpman (Post 2851626)

Unfortunately, all of these systems utilize single plain manifolds designed for carbs, then converted to EFI. So they're all going to be compromises. The runners are different for each cylinder, and plenum volume is WAY too small for max HP with EFI.

There's a reason EVERY production EFI system from cars to Merc. use a manifold that looks completely different than a carb setup, and it's not just to be different.

As far as programability is concerned, the only one of these I've used is the Accel, and it does what it needs to do for the automotive applications I've used it in.

I'm sure they'd all work to some degree, but as far as HP is concerned, I'm pretty sure they'd all be a toss up. If that's all you're looking for, just research the basic intake manifold as it is used in it's carb'd form. You'll end up with about the same HP.

If usability is a concern, you need to figure out what is important to you. I'm sure each system has it's plus's and minus's. The simplest system to program will probably also be the least flexible.

Regardless of the system you choose, remember, all of them are designed for automotive use. For marine, you need to make sure the ECM is away from any moisture, and that it's fairly well isolated from vibration, which is much more severe in a boat engine compartment than in an auto. Also, make sure the one you choose does not rely too much on an O2 sensor for continued use, but has the ability to use a wideband sensor for tuning. O2's (especially Wideband) are great for tuning, but do not work for long in a marine environment with continued usage.

I have the Marine Kit. The PCM is conformal coated. I have the PCM located in the engine compartment. Been using it for 5 years. However my boat is dry storage and freshwater use. If you store the boat in extreme conditions you could remove the PCM for storage. The water jackets on the intake have a coating on the inside. Other than that I am not sure of anything else that was marine specific with the kit.

Quote:

Originally Posted by MadMat (Post 2851651)

Do you know what's the upper hp limit on the 1000cfm manifold & TB before it starts to become restrictive?

The engine is a airpump. If you would need a carb bigger than 1000cfm then go with the bigger TB. I think you will be limited by injector size befor TB. I use 42lb injectors with 500HP. I could use a little smaller injector but then they just have to work harder. I had 30lb injectors and I had them maxed out on upper RPM. I have large Oval and I had to remove a lot of material to do the gasket match. They come from the factory more like a penut port. The rectangular ports may be a little closer.

Matt,
I have used the Cutler system for years. On a 513" motor at 6krmp I made 690hp, motor would run to 6300rpm, using 52# injecotrs. Cutler was sold time and again and it ened up in Holley's hands. I believe they use the same manifold as the Cutler. If there is a hump in the floor of the manifold it is the same, I believe.
The word on the street is the Holley ECU's fail. That might be old news, but I have not worked with one, just heard distaste for it.
I ended up moving the Culter ECU to a 565" motor and had a Hogan sheet metal intake made with two 1000cfm, and 65# injectors used. The Cutler ECU is self tuning and you have to know the tricks to keep it happy. I since have switched over to Megasquirt with P&H drivers and love the system. Fuel usage indicates 700-750hp
My new motor will be using a left over Cutler intake with a Fast 1375 cfm TB and M4 Procharger using the MSII with Peak & Hold driver circuits. Shooting for 1000-1200hp.

If you have been down the MS road, I dont see why you would cough up all that money for one of the systems mentioned.

Hope this helps.
Dick

To be honest, the master plan is to end up with MS, but I need to make a decision as to which manifold & throttle body is best - it looks like the 1000cfm holley setup might be plenty man enough for the job - I understand it's good for about 800hp before it runs out of breath?

Quote:

Originally Posted by MadMat (Post 2851632)

A great response, thank you.

I completely agree with your comments regarding choice of manifold. My original plan was to use the arizona S&M tpi manifold & 1300cfm throttle body, however a previous post indicated that this manifold & TB combo really can't flow enough air - it's absolutely maxxed out @ 600hp with high vacuum measurable in the intake. So that rules that one out.
That post, plus other conversations, suggested the holley 2000cfm setup was the one to go for over the 1000cfm, but I'm not sure where the changeover point is to go from the 1000cfm to the 2000cfm combo (on the holley system)

I would love to go with a kinsler efi setup, but I need to be pragmatic, and the $$ to go with that setup appears to be pretty prohibitive - I also really would need a crossram setup to keep the whole lot under the engine hatch, and they're even more proud of the crossram (rightly so, it's a work of art).

Unfortunately I don't know of any other TPI manifolds (the GM Ramjet manifold is oval I believe, my motor is rect), so that left me with the more "standard" style efi setups I listed above. Unless I start looking at tunnel ram manifolds with a TB on top, or a hogan fabricated one - I don't know much about either unfortunately.

I'm not at all concerned by the ECU or wiring side of things - the ECU will be well away from the motor and fully protected, and I'll almost certainly be making my own loom to fit. I'm also not worried about the software, I've built a megasquirt before so am fairly comfortable with tuning software and don't need it to be programmed just for dummies.

I'm kinda getting the feeling that the most perceived difference between the different combos I listed is in the ease of use of the software, and that the manifolds, TBs, injectors & fuel rails are all much of a muchness - which is a shame, I was hoping one really shone above the rest, but I guess it makes it easier because I can base the my decision on $ rather than performance.

Thanks again
Matt

I couple people I've spoken to say that with minor mods, the ASM manifold is good to high 600's. That's what I just got done doing. I removed the wall between the runners in the upper manifold and radiused everything well. I also made my own oval throttle blade. The entire process took me about 5-6 hours. No big deal and I know I've got a good manifold to start with. If you do the calculations on those runner lengths, it works out very well for the RPM range where you're engine would be making 600hp. All those manifolds tune around 7000 rpm, and all have bad plenum volume for max power with EFI.

If you've already done a Megasquirt, why on earth would you even condsider those systems? The megasquirt is much more flexible than any of them and the prebuilt ones are dead on reliable and dirt cheap.

Anyway, that's what I did this winter. I have the whole setup ready to be lifted back into the boat. Changed from a Dart single plane and Holley 850. It'll be interesting to see how it compares.

bc,
you may be right, the manifold tuned to operating conditions will give you some gains.. It will be interesting to see what happens..
Do you have a pic of this new setup?? I would like to see what it looks like.
Thanks.
Dick

I second what GPM said,pic out a real good carb intake,many have bosses already there to add injectors then buy the appropriately sized throttle body using gm type connectors,iac,tps etc to keep things simple. Buy a ecu and harness to run it. I'm putting efi on a Pontiac engine right now for my 74 trans am,I looked at all the available kits and just decided to build everything. I bought a edelbrock super victor and a fast 1325 cfm throttle body. Some carb intakes are now even available with the injector bosses bored out. The problem with most kits in my case and yours is they use lame manifolds so you can get away from that by doing your own set-up and in the end it doesn't cost anymore,Smitty

If I were going to start with a carb manifold, and IF I had access to a TIG (i do), I'd buy a straight runner tunnel ram for a dual quad carb. Then I'd cut out the top plate and put a plenum on it with a throttle mounted somewhere on the front or side of the plenum (believe it or not, air likes that flow path a lot more than coming in from the top).

Quote:

Originally Posted by Mr Gadgets (Post 2852148)

Here's some crappy pics I had taken at one point. You'll notice the new O-ring no longer goes all the way around. I figured some sealant right around that area will be sufficient with the both right there.