Quads throttle or Single throttle efi set up??

[WRCDAT]

Heres a topic that might be of interest to quite a few people on these forums with the age old discussion of which is best.... Would also be interesting to see your views/experience on the topic.

Heres what iv seen..

From the experience from the back ground where I was involved quad throttles look and sound fantastic, but are a good way to limit power. We proved this on numerous occasions, ie. one occasion customer went who went to where people would say is one of the highly regarded tuning shop in NZ / Wellington, then came to where I worked at the time which was a 8-9hr drive north of Welly (mainly for interest sake) and we re-dyno'ed the car which which had a trick set of quads on it, then we put a standard inlet manifold on with the standard single throttle and gained 10kw top end with out adjusting any fuel or ignition maps... and yes the all very important power curve was better also. Yes this particular car was a Honda, but we also proved this on starlet 4k eng and numerous others....GTR, GTi R....etc food for thought people.

When it came to working with quads, we found the ones from gtir were hard work to get good numbers from. Yes the numbers were alot better then standard, but when we fixed the quads wide open, then putting a single throttle from a rb20 onto the plenium it made the set-up a whole lot more tuneable = futher power gains . The 20valve 4age quad set up how ever was a much more tuner friendly set up with a good vacuum for map sensor, but again when building high hp 4agte (corolla wagon pushing 500hp atw) we went to single throttle, but on a custom inhouse intake setup.

Obviously in different situations individual throttles may be the best option due to space in engine bay / you want to hear a throaty intake.

What do you think?

[brocky41]

This will spark some good discussion - was interesting talking to you about this at work.

I think most guys just want the look and the noise - its pretty hard to make a standard SR or CA intake manifold (or any standard one) look good other than polishing or maybe some trick looking covers.

Its pretty amazing that you managed another 10kw without tuning which means potentially more power again on top of that.

[DJZ]

If they run individual throttle bodies in Formula 1 there's gotta be something to it I can't really see more throttle plate area "limiting" power, but there is a lot to the length of runners, how close the throttle plates are to the valves, angle of the runners, the person tuning it etc etc

Why run twin or triple carbs instead of a single larger carb?

My mates car makes 497rwhp on a single 65mm throttle body, it's a turbo car but the throttle body isn't the restriction to making more power.

[Evil13]

I always thought the quads were better for throttle response and for higher revving engines?
I'm just getting them because I want it to look oldish

[nick_m]

ITBs are way more picky to resonance tuning than a plenum setup. If you buy shelf ITBS and a Shelf header you'll just about be guaranteed to loose power. The ITB setup I bought came with 13" long runners, which is way too long for pretty much anything other than a diesel motor. They were originally a shelf setup for a hi revving honda motor. Go figure.
I think most siuations would be better off with a plenum, more forgiving and you can still definitely make awesome power on a custom plenum setup. If my ITB setup fails miserably ill probably test out a plenum setup
Where do you work WRCDAT? I would love to work somewhere that had a dyno

[WRCDAT]

I don't work the workshop anymore, as made the move south a few years back, but used to work at Speed Source - the owner is one clued up man. Was very interesting proving what can be done just by getting back to the basics and keeping it real.

Theres no real right or wrong answer to the topic, just personal preference.

Also might be interesting to see a if any one out theres experienced the opposite affect with accurate testing facilities i.e. dyno with your engine based on a production engine (as most are in the country).

Exhaust could be a whole new topic too. interesting how some of the cheaper ones out performed the far ken expensive ones,

Was fun changing things on cars strapped to a dyno to prove a point.

[nick_m]

yeah its interesting how many people just buy parts hoping for results
I've put a lot of research in sizing and selecting my parts so im hoping it pays off with good results. That said I also hope to continue testing once the car is running as much as funds allow. Most my testing will probably center around exhaust and cams though

[DAT620]

Heres a topic that might be of interest to quite a few people on these forums with the age old discussion of which is best.... Would also be interesting to see your views/experience on the topic.

Heres what iv seen..

From the experience from the back ground where I was involved quad throttles look and sound fantastic, but are a good way to limit power. We proved this on numerous occasions, ie. one occasion customer went who went to where people would say is one of the highly regarded tuning shop in NZ / Wellington, then came to where I worked at the time which was a 8-9hr drive north of Welly (mainly for interest sake) and we re-dyno'ed the car which which had a trick set of quads on it, then we put a standard inlet manifold on with the standard single throttle and gained 10kw top end with out adjusting any fuel or ignition maps... and yes the all very important power curve was better also. Yes this particular car was a Honda, but we also proved this on starlet 4k eng and numerous others....GTR, GTi R....etc food for thought people.

When it came to working with quads, we found the ones from gtir were hard work to get good numbers from. Yes the numbers were alot better then standard, but when we fixed the quads wide open, then putting a single throttle from a rb20 onto the plenium it made the set-up a whole lot more tuneable = futher power gains . The 20valve 4age quad set up how ever was a much more tuner friendly set up with a good vacuum for map sensor, but again when building high hp 4agte (corolla wagon pushing 500hp atw) we went to single throttle, but on a custom inhouse intake setup.

Obviously in different situations individual throttles may be the best option due to space in engine bay / you want to hear a throaty intake.

What do you think?

Thats a null test because of too many variables like altitude, temperature and most importantly Dynos. 10kw isnt even enough to feel in your foot. Did the quads and the Single have the same surface area? for a true test you would have to have tested and tuned both engine setups on the same dyno on the same day. As for the 4age that would makes sense because I would doubt the factory quads would be able to support 500hp.

[WRCDAT]

It was done the same day and time on the same dyno with an altitude meter, temperature gauge, baro pressure etc all inputs for the dynos computer system as per normal.... car left on dyno whilst work performed.. before and after dyno runs - so not a null test id say, proof to our theory for what was tested. a standard civic throttle plate was smaller then the quads surface area if all added together.. Personally i think 10kw is not too bad when looking at a gain from 150-160kw. Id feel it.

Shouldn't be a topic to rustle feathers.... maybe just looking for tried and tested comparisons to check notes basically, with others who have the experience. Could save alot of moo laa for the people who are getting into / looking at options to get there cars modified. When I started out as a mechanic I too wanted 4 throttles on my datsun just because it seemed logical.

[fletch]

injector placement means a lot also.
Most serious race engines have the injectors out of the trumpets. Not very practical on a road car...

http://www.youtube.com/watch?v=y2iBbwocYZw" onclick="window.open(this.href);return false;