site with fuel injection for straight eight .

[41buickcompoundcarb]

This was discussed before on here ,so I would post this site that has a lot of good info on adapters for floor shifters and headers plus intakes custom made .Then the fuel injection too . Have fun looking at this site . http://www.roadmachine.fi/Buick/may2005.html . This man deserves a thank you for his knowledge that he is posting on his website about his buick and the straight eight .

[Jyrki]

Well thank you - you make me blush!

I have long neglected updating my site. It's just that my workload has increased to a level where it's hard to find time/energy for my hobbies. But rest assured, there's going to be a lot of EFI and supercharging stuff coming over the winter! I just came back from the SEMA show in Vegas and got some new ideas.

[nali]

Oh yes Jyrki .....
Please keep on beeing a guinean pig , I d like EFI and supercharging too for mine ..

[lakester]

There is a discussion on landracing.com under Forums:Efi about a st8 efi unit.

[nali]

I already saw it .
The problem is it take a little more than hand tools and a cheap Megasquirt to make what those guys do
It seems we always go back to the same solution , keep stock or have a custom head build

[39CENT]

Just put a supercharger on it. Will force the air in.

[nali]

It s the easiest way .
Not to say I don t like it .
I m already trying this on a Rambler with a 232 CI and a Riviera Eaton
Just feeling tired , the Buick 38 is for Gabriel my kid . Anakin will have the Rambler .

[Jyrki]

I was finally able to put together my thoughts and update my site with some EFI theory for straight-eights. Enjoy, and let me know if you think I'm on the right track or if you think this is BS

http://www.roadmachine.fi/Buick/EFI.html

[nali]

First :
- Is 6000 RPM safe ? I know some Str8 run as high , but how long will they last ?
- 15 PSI boost . With custom pistons and rods ? Can we use so much on a stock engine ?


Now about the injection .
This took me a while to understand , so I made a draft on my way .

V1 : valve 1
I1 : injector 1
V2 : valve 2
I2 : injector 2

A : We want the I2 to open when the V1 close . V1 close at 251°.
It would be stupid to let I2 open while V2 is closed , or V1 will get the fuel later , running rich . So we close I2 at at or before V2 close , at 431° .
So I2 will be open from 251 to 431 = 180 °

B : I suppose it s logical to have I1 open the same lenght as I2 . So if we open I1 360° after I2 , it opens at 611° , but close at 791 ° V1 is still open . While I2 has squirted in an open valve , I1 squirt first on a closed valve . This valve will then be open for just 85° . Not the same pattern as V2

Questions :
A : even if we have the same amount of fuel in both cylinders , are 180° enough to fill them at 6000 RPM with 15 PSI boost ? It seems to be the same pb you mention .

B : will V1 open 85 ° during injection , while V2 is always open during injection , may cause a pb for tuning ?

I hope my draft is correct and my world clear enough

[Jyrki]

Nali,
I picked the 6000 rpm as a safe number for injector sizing, as there will never be a need to rev any STR-8 higher than that, although some of the racers here have revved up to 7000 rpm. Yes, with boost, we are talking forged pistons, but many experts here agree that the stock rods are plenty capable.

I'm going to use only 4 injectors (1 per port). You don't achieve anything by using 2 injectors per port, as they wouldn't fire simultaneously anyway. It doesn't affect injector sizing, either. 180 degrees being the maximum squirt window, you get 50% duty cycle with one injector and 25% with two injectors, and that's the only difference.

Yes, the number 2 cylinder gets it all on an open valve, while #1 gets part of it on a closed valve (all of it at idle) and partly on an open valve. I don't think the difference in fuel mixture will be significant, though.