8 Throttle Body Intake

[Lambo]

Itb

Damien, Have you pinpointed where the vacummn leak occurs is it where the adaptor plate meets the original runners, or is it through worn bearings in the ITB itself.

Regards
Lambo

 

[Damien]

The problem is that the bores in the throttlebodies from Carbontech are all over the shop. When EFI Hardware measured them up to make each butterfly they range from 44.2mm to 44.9mm. Also when I hold them up to the light the gaps aren't uniform so I don't think the bores are round.

I've had ball bearings fitted with o-rings so there are no leaks along the shaft.

It's difficult to get a well sealing butterfly which doesn't stick when opening/closing. OEM ITB's like what Ed is doing would be much better.

 

[Damien]

I've started a website to share my mods and I've put up part 1 of my ITB conversion which is an intro and covers all the extra bits. Part 2 will cover the installation etc...

www.v8soarer.com

 

[Lambo]

I believe NZsimon had issues with his Carbontech ITB as well , i found these pics i had salted away of his setup, another choice would be to have the bores rebored round and new b/f made, or have a look at these, but they are not cheap, http://www.rollingroadtune.co.uk/jenveyprices.htm another way to go would be like tmillar did and go with 4age ITB , had a ride in his car lovely noise and go !!!!! the first picture is of unknown origin., the other two are NZsimons setup

Regards
Lambo

 

[Damien]

First picture is mine : )

NZSimon's done a fantastic job with his. EFI hardware have sold a lot of their kits for the 1UZ and they've helped me a lot so I should have just bought one of their sets instead of getting my carbontech set overhauled.

 

[ed_ma61]

Ed, will you be using stock cams or something a bit more aggressive?

around 252deg @ .500" (equiv) and 11.5mm odd lift

give or take. ive yet to figure out this whole vvti thing, so duration doesnt mean much. its possible that even with a hell lumpy cam at idle the vvti will give large vacuum

 

[Damien]

Be very interesting to see how it goes. Where did you get the cams? Kelfords?

 

[ed_ma61]

no no, havent got them yet - waiting to actually get the heads back, will looks at the ports, get the flow figures, then talk to kelfords about profiles to suit

 

[Damien]

Got my car back on the road over the weekend... finally! Solved the problem with the butterflies sealing with nailpolish. Old carby trick apparently and it's enamel so goes rock hard. With the butterflies closed I painted around the trailing edges so when it dried it formed a small lip (like 0.05mm) for the butterfly to close against. That also made off idle progression much smoother.

I also fitted an SMT6 for ignition only and retarded ignition at idle which also helped control the idle speed. Spent most of yesterday with the wideband O2 meter sorting out the fuelling but I'll get it fine tuned on the dyno. It's running 12-12.5:1 at WOT which is safe for now and it sounds awesome - bloody quick too and the top end feels strong.

 

[Damien]

Received the custom airfilter which I ordered from Unifilter to fit over the base plate and trumpets. I'll only be using this until I get the plenum made up so I can then have airfilters behind the headlights to get cool air. Sucking warm air in from the top of the engine bay isn't ideal but at least it'll be filtered.

 

[rarson]

Looks very nice. Now I've got a question: with a plenum, once air gets flowing, the runner length would have less effect on power (at least at WOT) than it would with an individual setup? In other words, obviously we're severely limited for runner length tuning with this engine, so would adding a plenum and some extra ducting to the plenum effectively increase the runner length?

Either way, I think it's probably best to use a plenum with ITB's on this engine.

 

[Damien]

The plenum won't affect the effective runner length as the runners begin at the mouth of the trumpet whether they're enclosed or not.

 

[Damien]

Finally got my car all sorted. I fixed the issue with getting a good seal with some moly dry film spray which I wish I knew about months ago.

Got it dynoed yesterday and while the peak power is pretty good, it's the midrange and throttle response that's giving me a grin from ear to ear!

I've got more info on my website and I'll be finishing the write up of how I put it all together now I know what works and what doesn't - www.v8soarer.com

 

[sniper]

Please please post Video footage of your car, incar sounds, outside fly-bys, it must sound like nothing else on the road!!

 

[Damien]

You got it - I'll get some footage this weekend : )

 

[ed_ma61]

its quite incredible how low in the rev range these engines are tuned. id predict by your mods that youve already moved the rpm power band up around 1500rpm...

ed

 

[Damien]

Iit's a shame the stock cams fall right off by 6000rpm... but it makes sense for powering a heavy luxury car.

 

[Ghazzah]

Gents,

All very interesting! I'm 90% thru installing x8 red rebuilt 4AGE TBs on a pair of Tony Millar mainfolds, home made 60mm polished ali trumpets, red Unifilter sock filters, zero-backlash couplings between TBs throttle shafts, Summit fuel rails, aerofast couplings and miles of braided line, Microtech ECU. Going into a 950kg AC Cobra. Currently 0-100kmph 5 sec and high 12 qtr miles on stock 1UZ-FE. Traction is the biggest prob. Gonna get much worse real soon...

Stay tuned.

Gaz.

 

[Damien]

Nice! Got any photos?

 

[Ghazzah]

Yup.

Chocolate fish for the 1st person to identify the purpose of the custom gear sitting atop the stock scissor gears in the 4th pic. No prizes for the 5th.

GazMan.