Toyspeed.org.nz Message Board

by **atmosports** » Fri Apr 14, 2006 6:34 pm

Spotted this today while in at HiTech Motorsport, it's a quad throttle conversion using 20V throttle bodies for a 4Age 16V, have no idea of cost etc but I did see enough bits there to make upa few more sets.

http://atmosports.orcon.net.nz/20V/20v6.JPG
http://atmosports.orcon.net.nz/20V/20v5.JPG
http://atmosports.orcon.net.nz/20V/20v4.JPG
http://atmosports.orcon.net.nz/20V/20v3.JPG
http://atmosports.orcon.net.nz/20V/20v2.JPG

by **fivebob** » Fri Apr 14, 2006 6:48 pm

Interesting that they chose to use only #1 & #4 for what seems to be the pressure tap/ signal damper. Wonder if that would help to even out the pulsations in the MAP signal?

by **RedMist** » Fri Apr 14, 2006 11:58 pm

Agreed especially as 1 and 4 are paired.

Of more interest is the fact that it appears to be a standard webber manifold. Or the fact that the trumpets have a radical taper and only a 90 degree return and are so short you would need a quadrouple helmholtz refelection to get anywhere near optimal resonance. IE look good, but probably perform as well as I do after a double skin full.

by **escortman** » Sat Apr 15, 2006 11:13 am

im looking at getting one of these made up by evil si for my bluetop while i wait to put the blacktop in esky (which could be a while :lol:

) what sort of performance gain am i looking at and is it worth it for $360

by **Mr Revhead** » Sat Apr 15, 2006 6:28 pm

id say they are made for peak hp..... at some rpms..

but im not an ecpert on those things, but to me short before the butterflys and long after = high rpm power

by **3T-Rona** » Sun Apr 16, 2006 8:50 am

escortman wrote:im looking at getting one of these made up by evil si for my bluetop while i wait to put the blacktop in esky (which could be a while ) what sort of performance gain am i looking at and is it worth it for $360

simon made me a set and its awesome, well worth your money, u can pay easily over $400 for them elsewhere, without a doubt worth it wen u see the finished product

by **Adamal** » Sun Apr 16, 2006 12:22 pm

RedMist wrote:Of more interest is the fact that it appears to be a standard webber manifold. Or the fact that the trumpets have a radical taper and only a 90 degree return and are so short you would need a quadrouple helmholtz refelection to get anywhere near optimal resonance. IE look good, but probably perform as well as I do after a double skin full.

Looks like its for a bigport, so assuming you put the TVIS plate in there, what effect would that have on it?

no grip · by **Akane** » Sun Apr 16, 2006 12:50 pm

A friend of mine had an AE86 (built by lynn Rogers, for high RPM), but he had a problem with the quad TB's not giving enough vaccum (We took it into nite performance and the dude said so) to assist his braking (I had a drive, it was scary).

So if that's true, that's 1 thing to keep in mind.

the vac lines were linked 4 > 2> 1 IIRC to the brake booster.

can't remember how his map sensor was linked, but he was using a Link ECU for it, and it had it's fair share of problems.

by **atmosports** » Sun Apr 16, 2006 5:29 pm

Not saying your theories are wrong or anything but the trumpets on that setup where the result of 2 days dyno testing with regards to length/taper/radius & on this particular setup that is what gave the most gain with regards to peak torque 7 the rpm at which it's acheived. As for why they've taken the vacumm from 1 & 4 I'd say that to would have been tested & for some reason or another that's why it's like that. No worries about not enoguh vacuum for the brake booster to work as the car these are going on doesn't use a booster.

Why yes it is a weber manifold, but then if the customer has one & wants to save some $$$ then why not use one & save some time & money. It is also gives Hitech the chance to use some of their 20V throttle body to side draft adaptors.

by **suberimakuri** » Sun Apr 16, 2006 7:09 pm

nothing wrong with starting from weber manifold. It's not the tidiest, but it is an easy way.

as for pulling the map lines and brake booster.
you do lose brake booster assist when going to itb's.
the map signal does bounce around a little but you can dampen it (mechanically and with software).

ITB's make an awesome noise, give great response and are a must imo for a great na motor. (One builds NA for a reason).

by **Mr Revhead** » Sun Apr 16, 2006 11:58 pm

why must you lose vaccum assist when going to ITB? the stock 20v cars have it.....

by **fivebob** » Mon Apr 17, 2006 12:10 am

Mr Revhead wrote:why must you lose vaccum assist when going to ITB? the stock 20v cars have it.....

Can't see any reason why you should lose it either. Long duration cams yes, but not ITB's.

by **suberimakuri** » Mon Apr 17, 2006 12:32 am

it's not like it's gone completely.
Just pulling the brake booster off one runner rather than a single throttle manifold gives you less assist... especially at certain times.
same deal with carbs.

IIRC the 20v manifolds collect brake booster assist from all cyls.

itb's make your idle signal higher (closer to 100kpa).
cams do this as well. itb's are harder to tune.

by **atmosports** » Mon Apr 17, 2006 8:48 am

We've always just taken the vacuum off one runner when we've done carb conversions on escorts etc & never had a problem with getting the booster to work.The engine these are going on has got $&#$% all vacuum anyway due to the cams it runs, hence the reason the booster is gone already.

by **suberimakuri** » Mon Apr 17, 2006 10:49 am

yeah, that's what I'm saying, the booster works, but you have sfa vacuum compared to single tb manifold.

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