The V8 Owners Forum -

Looking seriously now at the problems to be overcome in making the 455 an EFi setup.

Bike throttle bodies are easy to come by but given that each of the pots on this engine is nearly 1000cc I'm not sure if I'll get the air flow through them that I need.

Realistically the engine will see no more than 5700rpm which means about 27lbs of fuel per hour or 280cc injectors with each pot requiring roughly 70cfm of flow.

Does anyone have any flow figures for something like a set of Suzuki TL1000 bodies (that's a 1000cc twin)

I think you will need bigger injectors.
I maxed out my 24lb LS1 injectors with a few psi of boost - raising the fuel pressure to 60psi to make the injectors look like about 28lb only gave me a few more psi.
I'm pushing about 400bhp on the chevy which has 60lb mototrons in it - which only ever hit around 50-60% duty cycle.
So I would say you should be looking in the 40+ region - depending on what you can source.

Rossco,

How are you planning to seal the valley if not using a one piece manifold?

Are you planning to make your own inlets to take the throttle bodies?

There are of course either single 4 barrel or double 4 barrel inlets available which can take throttle bodies instead of carbs or the inlets can be for port injection but starts to add up the $

Had a quick look around and came across this article which shows a seperator/cover for the valley which might be useful.

http://www.popularhotrodding.com/engine ... to_13.html

Kevin.

Eliot

Must admit I calculated that twice and still thought it was a bit low. I'll see whats available in 40+

Kevin.

Yes, sealing the valley is a simple fix and to some extent so is fabricating the inlets as I have access to CAD/CAM and laser cutters.

I've looked at the various bolt on EFi systems for the 4 barrel manifolds but to be honest while they all look great they dont offer much over a well set up carb. In fact some of the guys over at V8 Buick have ditched the bolt on EFi systems in favour of carbs.

There's also a bit of "No-one has done it this way before" involved here and I'd really like to see how this engine responds to a full sequential system

Fuel injection just makes it easier to make adjustments without having to mess about taking the carb to bits. You drive around dataloggging and then you can sit down at home look at the logs and decide what you want to change.
Not sure what to say about throttle bodies - they are usually associated with high revving engines with lumpy cams (which prevents charge robbing) - you application is [relatively] low revving high torque application.

Thinking of throttle bodies purely because it's an easy way to start.

I could fab a new manifold but to be honest why reinvent something that is already available off the shelf.

The alternative of course is to fit injectors to the standard manifold and use the carb purely for regulating the flow of air.....not pretty but would work

Hi Rosco
Throttle bodies work well on low reving engines even though they are associated with high reving units, you may want to design somthing with a slightly longer inlet length though. Another way of going would be an indy car style set up where there are two plenums over the valley with the inlets fed from both banks so as to give even pulses 180 degrees apart into both plenums and a TB on the front of each, effectivly like a duel plane manifold but with much straighter inlets. You could also adapt a cast tunnel ram into individual stacks by removing the top and extending the runners into TBs.
Best regards
Mike

Mike

I like the idea of the TB's and will be looking at what is the optimum runner length for low down torque.

Will also look at the Indy style plenums.

Currently looking at a set of Suzuki GSXR750 throttle bodies to assess if they can be adapted.

Hi Rosco
I would recon for a throttle body to be large enough for your engine you are looking at a bore of about 65-70 mm working on the basis of an SBC equivilant being about 62-64mm (less capacity but a bit higher reving) if you work out the area of a finnished port, convert that into an equivilant runner diamiter and add about 10% for the throttle plate restrictin and another 14% for the taper of the port to the throttle plate you should be in the right ball park. If you look at the throttle bodies for the vauxhall omega v6, 3.2 litre version, they are about 64- 68 mm depending on version, they come in pairs and could be a good cheep basis for what you want (ebay is you friend )
Like this http://cgi.ebay.co.uk/VAUXHALL-OMEGA-3- ... 255a85d6b2
Best regards
Mike

Mike

Interesting.

The advantage of using the motorcycle throttle bodies are that they come as a complete setup - linkage/injectors/TPS etc

Bike sized injectors may come up small for your gas guzzler - what power do you expect the engine to put out?

Rossco wrote:Looking seriously now at the problems to be overcome in making the 455 an EFi setup.


Realistically the engine will see no more than 5700rpm which means about 27lbs of fuel per hour or 280cc injectors with each pot requiring roughly 70cfm of flow.

Numvers must be wrong
70cfm *8 = 560cfm

Ford 302 fairly stock will run a Holley 650

Your engine is running 50% more cubes

289 race engine will run 48 IDA / IDF webbers (sure there is some restriction with tubes etc)

I know I can get my hands on a 4 barrel injector kit (Carb replacement thing) running 1000cfm if it iis of assistance

But it ain't cheap!

Ian

Ian

As I said above those figures looked low tome but they are at 70% VE.

I can get the 4 barrel EFi but to be honest I see no reason to go with that when a decent carb would be just as good.

The idea here is to do something that none of the 455 guys have tried before.

Hi Rosco
what heads are you going to use on this engine? I have a feeling some Buick after market heads have BBC exhaust flange pattern, I'm not sure what port pattern the Buick inlet is might be worth investigating to see if they are the same as BBC because if they are then there is the Hilborn route, much simpler than making a suitable inlet from scratch.
Best regards
Mike
Edit, just had a look and the ports are in the same arrangment ie in pairs so may be worth a look.

Mike


The heads will be standard Buick to start with and replaced next year with the alloy aftermarket heads from TA

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