su carb help please.

Post by **aussiemike** » Tue Feb 26, 2008 5:13 pm

Hi all, just wonderin gif someone oculd explain th edifference between a normal su carb and one form a turbocharged blow through set up???
cheers, michael.

I have seen ones from a non turbo engine being used with a blow through turbo also. Something about equalising pressure on both sides of the carb??

Post by **minor_hickup** » Tue Feb 26, 2008 5:34 pm

I believe the difference is that the throttle spindle on the turbo carb is sealed so mixture is not forced out the carb. Also boost pressure is applied to the float chamber so there is boost pressure + pressure from the fuel pump to stop fuel being forced backwards through the jet as the turbo applies boost. Normal carbs can and have been adapted. Practical performance car magaizine did this to turbo a rolls royce using the original SUs, HS8s i believe.

Post by **aussiemike** » Tue Feb 26, 2008 5:36 pm

Hi yep just been reading up on the rolls royce!!!! it was on that car that i saw non turbo ones being used. But they dont mention about the spindle having a new seal?
cheers, michael.

Post by **minor_hickup** » Tue Feb 26, 2008 5:39 pm

Have you got the magazines? I have an issue at home (100 miles from me) which I can dig out if you'd like? I can probably type it out for you at the weekend if i pop home from college. Unfortunately details aren't that great, more a brief description of the work done. Maybe its worth contacting the mag for more details.

Given how they've plugged this system as a brilliant way to blow through I feel they should do a feature on adapting the carbs. Perhaps they will as supercharging is a hot topic at the moment and being covered in a several part feature.

Post by **aussiemike** » Tue Feb 26, 2008 5:53 pm

yeh cheers fo rht eoffer but i have the mags. But as you have said the detail which is always the hardest bit is a wee tad lacking. I have just e-maied the editor asking for some more info!
cheers,michael.

Post by **Orkney** » Tue Feb 26, 2008 6:24 pm

Try sending a PM to Picky (know he's on the P*ss @ Uni ut should get a mail) and BMCOSSE - know they were both banging heads on the differences so might be able to help you out.

Post by **bmcecosse** » Tue Feb 26, 2008 6:29 pm

I know nothing! I do know it will be a whole lot easier to just use the carb designed for the job - Metro turbo carbs are cheap. Otherwise - go for fuel injection - either use a later Mini set-up or go Megasquirt.

Post by **aussiemike** » Tue Feb 26, 2008 7:01 pm

Hmmm o i have a fully programmable ecu for my engin now but as i live in a remote place i dont have anyone to help me with it so i ma wanting to simplify. So was htinking weber blow through but everyone o talk to say that i need one off of a lotus. Buggered if i can find one!!!!! so stumbled upon the turbo rolls royce using its actory carbs, su,s , and thought, hmmmmmmmmm why dont people use these more often??? yes i know i could get the metro turbo carbs but thye are a bit more pricey than the normal ones.
Bmecoose do you have a couple of metro ones for sale???
cheers, michael.

Post by **bmcecosse** » Tue Feb 26, 2008 7:04 pm

No sorry - but they are often on ebay - or try Minifinity forum.

Post by **aussiemike** » Tue Feb 26, 2008 7:10 pm

ok cheers Bm.
michael.

Post by **minor_hickup** » Tue Feb 26, 2008 8:09 pm

I believe the carb lotus used was a dellorto. However Janspeed used a weber or dellorto to blow through on a turbo setup. Does anyone have a copy of vizard to hand?

Post by **aussiemike** » Tue Feb 26, 2008 8:11 pm

I have one in the house somewhere.,,,,,goes off to look.

Post by **aussiemike** » Thu Feb 28, 2008 9:19 am

well i have spent the last 4 days trying to track downa business that can modify a weber/dellorto to suit a blow through turbo set up but they all told me the same thing......find a delorto off of a turbo lotus esprit and use the bits off of it. Hmmmmmm needle/haystack.?
So I also spent hours reading the vizard book last night and although it wa an excellent read it doesnt really go into detail about how to mod the carb or if the non turbo HIF6 su can be used or not.
So i have no idea how the boys in practical performance car mag did it, the editor couldnt really help either and sadi he would get that Charlie to give me a ring. But I reckon he probably has other htings todo.
So still looking for carbs and more advice guys.
cheers, michael and thnaks for all the help so far.

Post by **dunketh** » Thu Feb 28, 2008 10:55 am

Pop along to a Ford forum and ask about the Fiesta TT Kit.

This was installed to a pretty much standard Weber TLDM or DFT carb, both of which might be an option given the correct manifold and jet sizes.

I believe there were instructions in the TT install manual that showed what simple mods had to be done to either carb.

(infact Turbo Technics made kits for loads of car/carb combinations so there may be even more options)

Post by **aussiemike** » Thu Feb 28, 2008 11:08 am

Oooooooooh good point about turbo technics. Wow i have been thick, one of m good mates dad owns the business. Right I am off ot e-mail her now.
cheers!!!!!!!!!!!

Post by **bmcecosse** » Thu Feb 28, 2008 10:55 pm

It is probably as easy as arranging simple seals for the throttle spindle (O rings or similar may do it) - and connecting the normal float chamber 'breather' to the ingoing pressurised air supply.
Edit - and also ensuring that the little air feed holes on the inlet face of the carb are open to the pressurised air supply!

Post by **minor_hickup** » Thu Feb 28, 2008 11:14 pm

I believe the dellorto carb is a 45m, i haven't seen any about and I believe they're quite sort after. I hope Charlie Broomfield does get back to you as I'd like to know how difficult it is to modify the standard SU carb

Post by **aussiemike** » Thu Feb 28, 2008 11:49 pm

yeh i woul dlove to know how to do it with an su too!!!! But things have prigressed and i am now in the possession of an lovely 48mm side draft dellorto which has had a wee bit of custom work dont to it. I also have the company who can supply the bits for the carb and all i need now is to find a company to do the mods to the throttle spindle shafts.
cheers, michael.

Post by **bmcecosse** » Fri Feb 29, 2008 12:37 am

Tour of Mull for you this year then !