AFRs

[Jono]

New poster! (less than 10 posts)

Happy New Year everyone!

Easy question for someone in the know....

Whats AFRs should I/we be aiming for? Do i need to run a richer for higher boost levels or can it stay the same. ie 15psi AFR is the same as 20 psi AFR


Some guidance appreciated!

cheers

[stuTHC]

If you are upping the boost to 15psi on a std carb then you will need to adjust the fuelling. There's loads of info on the site about carb settings, have a search of the articles and forum using 'carb', 'fuelling' and 'afr' as your search words.

The 4th post on this thread is a good starting point thou-

http://www.rtoc.org/boards/showthread.php?t=1685&highlight=fuelling

:)

[Jono]

New poster! (less than 10 posts)

well... im currently running a so called group A carb from a well known tuner :-). Though I suspect it doesnt fuel correctly and is probably responsible for my head gasket failure some 18 months ago. My 5 has been off the road since due to other reasons. However im now in the process of putting it back on the road, well to be exact, that engine into a new 5. I was also planning on converting to fuel injection, but im initially going to get it running with the carb first. So really im just on an info gathering exercise!

[stuTHC]

grpA huh? well know tuner huh?

Start again.
Do your reading on here, get the car built up and running, stick a probe up its ass and go from there. If your planning on going efi eventually a good wideband will be essential anyway. :)

[jure]

New poster! (less than 10 posts)

Happy New Year everyone!

Easy question for someone in the know....

Whats AFRs should I/we be aiming for? Do i need to run a richer for higher boost levels or can it stay the same. ie 15psi AFR is the same as 20 psi AFR


Some guidance appreciated!

cheers

In short, Yes. You are always aiming to have same AFR in all conditions. Everything else is already said.

[RussellT]

Come on Jono mega boost, a lead right foot and the fact you tried to rebuild the turbo might have something to do with the head gasket failure. Also wernt you playing with the jets yourself? :wasntme:

As for AFR as you get above a bar you need to run slightly richer to help gaurd against pinking. I was told 11.5 is a good AFR to aim for when at full throttle under load.

EFI I admire your ambition I look forward to hearing how you get on :coffee:

Russell

[Jono]

Howdo RT. Happy New Year!

I resent those comments! lol Initially I did fiddle with the jets but it wouldn’t idle properly so I then had the whole carb rebuilt and I haven’t touched it since. It’s still sat on my engine with the jets the tuner put in. Re my turbo I bought a stage 3 jobbie at a cost of ~£700 it lasted a few months and then smoked like mad. When I stripped it the bearings were goosed and I sent it away to be rebuilt where it was condemned! :cry:

Re EFI, if some kind person would send me a picture of their EFI inlet manifold so I can shamelessly copy it that would be great!

On another note, I purchased a Helmet and race suit on Friday, so I’m now kind of committed!

[RussellT]

I think that blaming others when your car blows up could be considered a prerequisite to be a member of this club. :wasntme:

there was a French guy at the national day with EFI on a 5 using the inlet manifold of another Renault ? a 16 If it fits the head that would be a lot cheaper way of doing it. Mudslinger or Miller in Scotland can help you on the bespoke manifolds.

To my mind to do it properly you need the Gordini cross flow head as Andrew Cooke has on his 5

[Sparkie]

it was off a renault alliance - usa spec only. he waited 2years for one to come up on ebay? rarer than a raider badge or a new towing eye cover...lol