I was going to go with the holley tbi to carb intake adapter until i read a few posts about the bore being off centre.
I have heard about a place called PAW but cannot find a listing/email address (I live in the UK).
I have also heard about a place called turbo city.

are there any more suppliers ? the holley one looks kinda pricey for what you get.

what about a combined "tbi adapter/nitrous plate" has anyone heard of these. I was going to fit an edelbrock performer RPM intake but looking at the height it might be tight for clearance under the bonnet especially if i add an adapter and maybe a plate. Now i am kinda thinking that i should be trying to match the intake to the cam (which will be a an LT4 that shifty sold me).

so i guess the question should be,
I am fitting an lt4 cam so which intake, with an adaptor for tbi and maybe a nitrous plate will fit under a stock bonnet and complement the cam best.
should i be considering a single plane...if so does the bore centering become more or less critical ?

 

I have a TurboCity adapter, and it's centered nicely over the manifold. Oh, and see my setup below...

 

http://www.tdperformance.com/pdf%20p...Iadapters.html

http://www.painlessperformance.com/catlarge/60118.jpg

http://www.cfm-tech.com/catalog/tbi_...ate_549472.htm

http://www.turbocity.com/default.php...fca566cd132133

 

I've heard the off centered ones actually make more power. If you put the bore towards the front it makes better numbers. Not sure who dynoed it but I know someone did. The center will probably make as much power as the foward position, but putting it in the rear is the worse out of the three.

 

I tried both a centered unit and one with the TB forward. This on a single plane on a BBC. The centered adapter caused my rear cylinders to run rich, which a BBC is known for anyway.

 

is there anyway that the holes could be elengated fore-aft and then the plate moved to get the best mixture distribution ?

if so then the plate with the most meat around the holes would be best surely.

or is it that at idle the fuel all seems to drip from the lowest part of the throttle butterfly but at WOT it does not.
That would mean you would need some solution that at idle the low butterfly point was at centre but as you increase throttle the plate would move back to centre the whole bore.

Do we have any fabricators with jolly clever ideas ?

 

worrying too much about mixture distribution based off of where the tbi mounts on an adapter plate isnt going to gain you much...

the changes in performance etc... are going to be pretty minimal.

 

i think part throttle the butterfly directs the mixture either to front or rear. cant recall. so that is why the offset? part throttle operation is 95% of your driving. if you are only doing drag racing, centered may be best. trade off. my howell engineering adapter plate(1/2 inch) is 3/16 inch off center. at wot not sure how it will react. going into common single plane plenum, maybe no big deal.

 

im just saying... if you are worried about 1-3% power loss/increase durring daily driving you're being way too picky, there is better ways to look somewhere else to make 10-20% more overall... instead of hairsplitting on an adapter. If if i had to give 20 bucks to anyone who could guess if i moved his tbi 3/16ths forward or backward... i'd have 20 bucks. forever.