Fuel Injection / Megasquirt / Engine Management

[adequatespeed]

I am toying with the idea of going for fuel injection with individual throttle bodies and a megasquirt & megajolt system or the Emerald ECU

http://www.emeraldm3d.com/em_m3dk.html

http://www.twminduction.com/ThrottleBody/ThrottleBodyV8.html

This should give drivability and mid range performance improvements as well as preventing the flooding under breaking caused by the fuel in the carb spilling into the engine.

There is a significant challenge and a lot of unknowns in doing converting my engine to EFI, for example what size injectors to I need, how can get an initial map going

I have had a look at

http://www.megasquirt.info/

The result has to be a better engine than with carbs. Anyone got any experience information or ideas?

[mikelr]

Here's some info that will help you size the proper injectors for your application,

www.rceng.com/technical.htm

As far as setting up a base line fuel curve to get started, that all depends on what fuel management system you use. Most will give you the tools that you need to get up and running, than it's just fine tunning from there.

Here's another site you might want to check out,

www.electromotive-inc.com

Fuel injection is definetly the way to go on a car with such high cornering g-force capabilities.

Good luck,

Mike R.

[eliot]

Ive got Megasquirt on a chevy (but not in an Ultima ) works very well. Megasquirt(n-spark) will do your ignition too, no need for megajolt. There's something very satisfying about adjusting your timing with a few taps of a keyboard rather than having to pick a spanner up.

Ive documented my complete install, including the subsequent upgrade to twin turbos here:
www.mez.co.uk/megasquirt.html

[davefiddes]

My megasquirt install is sitting in a great big pile of boxes at the moment so I can tell how easy it is...yet. I did convert my old mech advance only dizzy to run with the spark portion of MegaSquirt-n-Spark over the winter. A very trivial job that has made the car a lot more drivable. The Megasquirt kit is very easy to work with and the support is excellent.

Interesting looking manifold your linked to. How much are they likely to set you back?

[eliot]

Megasquirt is MAP (i.e. vacuum) based, so you will need to figure some way to bring all the individual runners into a small chamber for it to measure. It's been discussed on MSEFI a few weeks ago.
Or you could use alpha-n mode which uses the throttle angle to determine engine air flow requirements.

[GreenV8S]

eliot said:

you will need to figure some way to bring all the individual runners into a small chamber for it to measure.

Is that really necessary? Won't all the runners show roughly the same depression if the throttles are synchronised? If not then surely the air distribution must be way out and you would be in trouble using a single MAP sensor and equal fuelling anyway?

[trackcar]

i think the problem may be to do with the pulsing effect of using one port to feed the vacuum to the map sensor .. linking all 8 together will reduce this, then using a suitable length of tube to the sensor should eliminate all pulsing effects within reasnoable bounds.

[GreenV8S]

Ah yes, that does make sense. Would it be possible to smooth the signal using some devious restrictor, sort of averaging over time instead of space iyswim?

[gtrclive]

The Kinsler system I have has 8 small pipes going to a small manifold (3/4" hexagon bar drilled out), then the MAP sensor takes it vacumn of that. There only small nipple screws with a push on pipe arrangment. Should be easy to do...

[eliot]

there are different ways of doing it, but essentially you want a smooth average of all the pots to avoid the pulsing of a single pot.

[steve_D]

If I wanted to go EFI where would I get a ready prepared manifold and throttle body.
I could do all the megasquirt bits and the fuel system mods but machining and welding the manifold is beyond the capacity of my garage.

Steve

[eliot]

Are you still talking about the TWM bodies? - they look pretty much complete to me.

People have scored old edelbrock/holley injection systems of ebay just for the manifold and TB and drove it with megasquirt.
Lance's corvette:
http://members.shaw.ca/corvette.1984/MS.html


You can get Victor Jnr manifolds with injectors on them allready i think (or at least the bosses)

Use a TPI setup - although its all done by ~5000rpm. Or reuse another factory manifold.

search around - they do exist, it's a chevy afterall!

>> Edited by eliot on Thursday 4th August 07:27

[davefiddes]

I've got the Holley single plane EFI manifold, fuel rails and throttle body. Just bought them from Summit.

www.holley.com/products.asp?product=9900-171
www.holley.com/products.asp?product=9901-101-1

[crafty]

Here's a very tasty 8 throttle setup for an LS engine.

www.harrop.com.au/root_folder/harrop_manifolds/amfd7022-00.html