500 efi intake
 

I hear that a limiting factor on a 500efi is the intake.
How much hp can the motor produce before the intake is a restriction.
What is the restriction - is it the throttle body? Would using a larger bore throttle body fix it.
Thanks
Matt

I have modified 500efi's (540's) and the intake is a restriction. We used a larger TB, ported heads, cam and made 630hp.......could have made more but I like EFI vs carb.

I spoke with Jim V. he said that a touch over 600 is about all that is there. He said it can be ported and it will help. It is in the port area where the two manifolds come together. There is not a lot of material to work with. Remember if you get an honest 600 plus, that is a large improvement considering these engines are coming through with only an honest 470 to 480 HP.

I'd like to put one on a 540 bulldog.
Are there any other elegant efi solutions?
By elegant I mean not just having a 4 barrel throttle body on top of a "normal" manifold.

The throttle body on top of a "normal" manifold may not be elegant, but it works. I have tried with the 500 intake and like everyone else, made just over 600 hp. I had the largest throttle body made at the time(1300 cfm I believe), extrude honed, shortened runners, hand porting, etc. It was on a 555ci BB with 10:1 comp, fairly large hyd. roller, Dart Pro1 heads, etc. Engine would only pull to 4800 rpm and then fell on its face. It should have pulled to 5400-5500. Went way rich past 4500 and pulled a ton of vacuum. I left it on the dyno and pulled the manifold and put on the Holley set up I normally use. With no other changes, the engine made 80 more hp. With a little fine tuning, it made a total of 92 more hp over the 500 intake.
Eddie

That's a good point, thanks. Form should follow function.

In that case, what is the best injection manifold & throttle body combo - I am keen to go injection. Not fussed abut the ECU - will sort that out seperately.

I really like the set up from Holley. I think it is the Commander 950. The only things I buy from Holley are the manifold, 2000 cfm throttle body, and fuel rails. I use a Mefi 4 ecm and harness, so I do not buy any of the electronics from Holley. I can not even count how many systems I have used and it works really good and is very clean.
Eddie

A 500 EFI intake won't work on Bulldog. The Bulldogs are tall deck blocks.

Talk to the guys at FAST, they have a complete BBC fuel injection system with everything including the intake, throttle body, injectors, fuel rails, harness , hardware and programmable computer which on your 540 will make all the power you need! Just ask for a tall deck intake with it.

Best Regards,
Ray @ Raylar

I have run the 500 intake on a tall deck before using spacers. I wasn't crazy about it but that is what the customer wanted. It worked fine, but still didn't make any power.

The Holley kit I was talking about in my previous post is also available in a tall deck version.
Eddie

I made hp in the mid 600 range on my 540 dynoing it on Crocketts dyno (with no accesories but it did have cmi headers on it) using a extremely ported/machined 502 mpi intake and bored out throttle body. It too went rich at about 5500-5600 on the dyno and went rich in the boat at about 5200 plus when fine tuning the mefi on the water,Smitty

Some of the old Kheikhafer injected race motors had spacers!:drink:

But, setting 600 as a target, It wants to be an "easy" 600, without having the motor trying to fight the inlet to get enough air.

You are right that it is not an elegant solution, and although it will work it is by no means optomized. The design compromises for a carb manifold are not the same as an EFI manifold.

A typical single plane carb manifold has too small a plenum volume for best power with efi, and the runners are unequal length and too short. These are compromises necessary when the manifold needs to distribute fuel as well as air.

We recently had another thread about the HP500 manifold and porting. I'm guessing that if all you're looking for is 600hp, the Hp500 manifold with a little porting is probably the best solution currently available for reasonable $$.

The Holley manifold will make good HP but you lose alot of much needed Torque getting rid of the long 500 intake runners.

Thanks for all the answers guys.

I guess the next question is what's needed to get 600 from the bulldog. Will it need both heads & exhaust? Or can the heads be pocket ported and that will do. How much HP can you get through a GIL exhaust.

Leaving everything other than the inlet "stock", how much extra can be had, if any, from a different cam.

Cheers
M

What about using a tunnel ram(fairly long runners) and adapting it to fit a 2000cfm throttle body?

I have a Paul Phaff 598 with a ported arizonza speed and marine intake on it which makes over 700hp and 730 torque. It does have a huge cam to compensate on the intake restriction. Its a sleeper when you pop the hatch and it looks like a 525.

Here is a picture of the motor

johnlomant,those runners are shorter than the hp500efi manifold.It probably flows more too.At what rpm is your max tq?

4500

I didnt know that, but it makes sense

I'm confused, what do you mean by this. That is the hp500 manifold

I am more confused; how does a huge cam compensate for an intake restriction?

Allowing more air in on the intake stroke to compensate for a restrictive intake manifold

Anyone care to elaborate more on this?

or a pair of 1000 cfm throttle bodies. No adaptation required.

I have a 500 efi bored to a 540, AFR heads and Tyler Crocketts Throttle body mod which mount the throttle body on top of the manifold. Dyno'd out at 693 HP.. Jeff Wurl

Talked with Tyler I'm looking at preventative maintenance on head gaskets,springs motor has 280ish hours on it. Not looking to touch the bottom end. Like to keep the appearance of stock as well. He's putting me together something. Looking at around 600-625hp

I have 502 with a stock bottom end,except for the balancing and gapless rings,Edelbrock large ovals flowed 340@600,42lb ford greentop injecters and Arizona Speeds Ramjet intake with their 1050cfm throttle body and billet fuel rails.The engine made 598@5200 and 670tq at 3700 with a stock merc. fuel pump.The intake was just port matched.Tuned the computer in the boat with MEFI BURN system.Starts great,idles flawless and we were able to improve the the shift into gear.Shifts better than the stock setup.No clunk.

So your saying a stock 502Mag makes more HP with a ecu reflash and a throttlebody than a HP525efi??? I'm curious to see that dyno sheet. Not doubting just curious.

I have aftermarket heads,cam,rings and my compression was raised to 9.8.I'll be happy to email the dyno sheet,Bob:coolcowboy: