My l16 draw through turbo setup....having issues, HELP

[fiveoneohray]

Thanks for the info & dig your set-up/dime! I am currently building a SU draw through myself and hoped you could give me your advice on a couple questions I have. You mention a single Z SU is a bit small for the bigger L series engines. I am hoping to build this for a L20 but I am thinking that even the 2" Jaguar SU is not enough carb for that displacement and a dual carb to turbo would be tricky / complicated system. In your experience do you think its possible to build a draw-though for a L20 with SU's or should I look towards a smaller displacement block? Also curious to what kind of timing you running and any other advice for us nutty SU turbo guys, Thanks!

 

Its hard to explain but the single Su should be able to breathe enough air. The tuning of the carb will be a bit difficult as the jet will need to be drilled and you will need to profile the needle down pretty aggressively. I would start with the needle. Another way to do it would run a single dual barrel carb like a phh mikuni or webe, just run a 40mm but it will still be a bit big and hard to tune.

 

With draw through things are a bit different than in a na or blow through system and actually less carb is needed comparatively.

 

What you really need to concentrate on is have as little upward moving air after the carb and match port everything to keep from pooling. If everything can run downhill, that would be ideal as fuel air mixture is heavier and likes to go down.

 

You will need a turbo with the correct seal so as not to pull oil out of the center housing when the throttle is closed.

 

As for timing the least expensive to retard timing under boost is look for a MSD BTM. I have heard of messing with the plate in the distributor but I have not personally done this. Currently I am running 8deg advance at idle and no vac advance. I just havent installed my BTM. It idles great, has a little bog right off idle, great under acceleration, then gets a little pingy at wot and full boost. My engine is over 11:1 so its gonna be different for you. Current boost is at max 5psi.

 

Hint L28et or vg30et turbos have the correct seal for draw through.

[spudly13]

QUESTION for anyone who knows anything about turbos. In its stock application the turbo im using had an oil feed line that was bolted diretly to the top of the housing. the drain was directly on the bottom. Can you rotate the turbo and lets say 90 degrees and have the feed on the said and the drain on the side?

[hacked521]

You can but your turbo wont last very long, as in about a 1/4 mile. You need the drain and feed tilted no more than 15 degrees past straight up and down. You really don't want the turbo tilted past that, the oil will either take too long to drain out and coke up or just not drain at all causing bearing failure.

[sssr20det510]

QUESTION for anyone who knows anything about turbos. In its stock application the turbo im using had an oil feed line that was bolted diretly to the top of the housing. the drain was directly on the bottom. Can you rotate the turbo and lets say 90 degrees and have the feed on the said and the drain on the side?

Some turbos you can take apart and flip the center center section

[hacked521]

Some turbos you can take apart and flip the center center section

 

yeah meant to mention that. :thumbup:

[sssr20det510]

On a draw through set up it has to have special seals in the turbo you cant just use any turbo ( on a side note there is a blow through carb and box on ozdat for sale for like 75 then you can run an intercooler and any turbo)

[spudly13]

Haha thanks guys, i had it all figured out about a week ago ;) Figured my old Suck through thread would have been the quickest way to get an answer!

 

I ended up taking it apart and clocking the intake and exhaust.