borgue

hey guys, i got an elford turbo car from the uk.

looking to make her a bit quicker, it uses a draw through su carb and a t3 turbo with no intercooler.

as a stock car it runs 4-5psi (ithink) i was hoping to up the pressure using water and methanol as charge cooling.

the car has a completly stock bolck, with underdrive pulleys and double belts.

was unsure if lowering the back pressure would help move things along? at the moment it is using an elford header with the stock back section. would going striaght through help?

thanks Ollie

RacerX7fb

Yes. Freeing up the exhaust will increase boost.

borgue

ok cool will it bo ok to go straight through or do i still need some back pressure?

inuissus_cendi

not on a turbo, you shouldnt need any backpressure at all. get that exhaust outta there

borgue

side exit it is then! with a screamer pipe!

mwatson184

You should retard the ignition a few degrees to be safe. Sounds like you have a pretty good idea about everything though. Should be a pretty solid setup once you get it running.

-Marques

inuissus_cendi

I wanna see that! post pics when youre done. Good luck

borgue

ok the plot thickens!

the oil temps are slightly higher than i would like due to the combination of 'beehive' and air cooled turbo combo!

have just acquired an fc oil cooler and am about to follow this mod

https://www.rx7club.com/1st-generation-specific-1979-1985-18/how-install-fc-oil-cooler-1st-gen-write-up-pics-462460/

this guy is a genius! but i use the oil passage at bottom of block below the oil filter to supply the turbo with oil, what is the best way to have an oil cooler and a turbo feed?

I thought oil from outlet below oil filter to feed the cooler and then the return from the cooler to the turbo??

the turbo drains to the sump via a baffle.

any help greatly appreciated!

Ollie

trochoid

iTrader: (6)

Well the 'genuis', , here says don't put the turbo in the loop with the cooler, too much flow and pressure. I have never seen an Elford set up, and am not sure about the size of the oil supply pipe to the turbo, but the flow directly from the oil cooler will be to much and blow the seals. If you follow my write up and use the FC banjo bolt at the bottom of the rear iron, then tap the end of the banjo bolt for the turbo feed.

After looking at the oil flow diagram in the FSM, if you routed the oil cooler directly to the turbo, a good portion of the oil supply would by pass the engine and none of the cooled oil would go to the engine, internally, it would be returned to the sump to be picked up again. Not a good idea if your oil temps are running high now.

borgue

ah i c! the supply for the turbo is quight small (not sure of evact size!) but i think you might have just hit the nail on the head!

ill have a look as soon as i get a chance! ill try to post some pics up to show problem and remedy.

are the the banjo bolts m18? i think my turbo feed pipe is 1/4bsp? so i might be ok!?

so the oil would be split between the turbo and the cooler? would the pressure at the turbo drop?

Cheers Ollie

trochoid

iTrader: (6)

Since the original feed is coming off of the rear iron, there should be no pressure change for the feed. The critical part will be the amount of oil going to the turbo. 1/4" bsp is not that much different than our npt threads and the banjo bolt will accept a tap of that size. Just don't tap the fitting too deep as to interfere with the flow through the banjo bolt.

Use as much of the original oil feed lines that you can to simplify installation. Can you post a pic of the fitting at the bottom of the rear iron?

I've been called professor and MacGuyver before before, I'm a few points short of 'genius', but thanks anyway. Glad you found the write up usefull. My engine now runs too cool in the winter weather, probably need to change to a 190* thermostat.

jes

I used to run the first version Cartech drawthough carburated turbo setup. First off be careful with the boost on a non-intercooled turbo... I was running ~6 # of boost and by the time the small IHI turbo fried the first time at 15K miles I had already flattened the apex springs and completely burned (as in no evidence they existed!) the rubber part of the 2-piece corner seals from excess heat. The only reason I knew was I got bored waiting for the turbo to be rebuilt and pulled the engine to port it. After that some of the changes I did were:
* solid corner seals
* 8 # boost
* high volume fuel pump
* 50% ethyl alcohol injection, boost & rpm controlled (methyl alcohol attacks plastic & rubber...)
* filtered turbo oil feed using Racing Beat's gauge adaptor block under the oil filter.

Tapping oil from the oil cooler line banjo bolt is before the filter...

BTW I have previously scanned the Elford sales brouchure.

Good Luck and have fun.

sdminus

Out of interest how much water/methanol do you run and how did you work it out the ratio. i presume the wi is virtually direct port. If you have any pics of you install it would be great

Scott

sorry for all the questions trying to achieve a greater understanding

REVHED

I don't get what you're trying to do. Why don't you run the oil cooler lines as per factory? The fitting in the front cover feeds the cooler and the return goes to the rear plate. You can then tap the rear plate fitting for the turbo oil feed.

Another good way is to use an early tall style oil filter pedestal and tap that for the turbo. That way you're feeding it filtered oil.

jes

I was running a 50% mix of ethanol. It's available as denatured alcohol, shellac thinner or moonshine. I used a Spearco controler IIRC set to start injection at 4K RPM and maybe 4# boost. From there it increased to it's maximum delivery as boost and RPM increased. I was using a spare windshield washer tank with motor to a nozzle over the carb. Going down through the venturis and through the turbo insured that everything was well atomized before it got to the combustion chamber.

The whole setup added an "interesting" oder to the exhaust. I remember a co-worker commenting upon returning from lunch after I put away his supercharged Thunderbird that the exhaust had a funny smell when I got on the boost...

If you still want a picture I have to dig around...

borgue

ok the cooler is in but not connected. gotta decide between the filter neck method and the rear banjo for oil to the turbo!

drove her to the workshop with only a header and it came onto boost so fast! bit of creap though! haha. got a wideband o2 in now so its all go for tuning!

any hints with SU carbs? got a couple of books but must admit im more used to fuel injection!?

picks to folow, just got to blag a camera! lol

on another note removing the diff to weld tomorrow! just got to get the driveshafts out.

have a good holiday!

Ollie