Austarion

i was just woundering would there be any benerfit to put 2 throttle bodies on the side rather then one on the end of the intake? (provied there was room)
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Yamaha rd56 specifications

That would all depend on your I/C piping. If it is only say 3" wide, then a 3" throttle body would be adequate, otherwise you would loose pressure. And it also depends on your Turbo too. You see the twin and so on throttle bodies on the big V8 NA cars because there is nothing else that forces the air into the intake. It would be a waste of time and money and I think you would get a performance decrease. The only option would be if you had Twin turbo. Then the twin throttle bodies would be a very good idea. one per I/C piping (2 turbos, 2 IC's, 2 throttle bodies, might be a good option)

Ive been led to beleive that multiple throttles, allowed for faster engine response but could be limiting to top power. Seen a lot of 4 cyl Toyota's and Nissans with quad throttle bodies.

Dont ask me the theory on that one, Im not quite sure myself.

Yes more then one throttle body is good, but not for a turbo unless you do what I said previously. The more throttle bodies, the more air flow, but when it is restricted at the start of the line (i.e. Turbo) there is no use.

hhhmmmm twin turbo 2.6
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Mflb Vaporizer

if you have a set up like this

1 turbo 3' pipe into intercooler then splits from the intercooler into 2 3" pipes for thre twin throttle bodies there will be a drop in presure

could you prehapes drop the pipe down from the intercooler to 1.5" to each throttle body that way there would be no presure drop?
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Mercedes-Benz R230

Yes, there would be a pressure drop, so you would change it to twin 1.5" piping, but you would get a better response with the standard 3" through, but then again the twin throttle would look nice

interesting note on TB's. anyone ever looked at a LPG gas TB off a V8? they look over 80mm and are a very nice unit with a 4 bolt flange on one end. also have no crap hanging off them like water lines and shite......................................... i'll shut up now :(

what actual comes off the throttle bodies? i know there is the throttle cable where else is there?
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Dan Gurney

Article in fast fours in the past couple of months.

Most high compression engines and japanese motorbikes (running in vincinity of 12-13:1), use multiple throttles to reduce detonation.

I'd highly advise reading the article, as it was quite a good yarn.

logik

just a bit of imfo on turbo's and multi TB. the skyline GT-R has twin turboes and six throttle boddies and they are one of the most feared jap sports cars, their set up runs fine. a friend of mine has turbo charged a 20valve corolla motor and kept the factory quad throttle bodies. it make's 238 kw at the wheels. its very responsive, drive's like a normal car until 3800prm after than hang the f*%k on. they work fine as long as you can work a single TPS off all of them and they all open and shut at the same time. on the other hand tunning can be a world of hurt apparently.

the biggest pressure drop in a turbo system comes from the intercooler. having multiple tb's won't have any affect on pressure but depending on the complexety of the set up maybe a bit more lag.

Zoom magazine fitted twin throttle bodies to their Project Excel. The reason they did is because they had boost planned for it so bought and fitted a boost gauge that measured vacuum also. The passenger noticed on full throttle there was still vacuum displayed on the gauge. I used always think my boost gauge was innacurate not showing as much pressure as was there because until it came on boost it would read below 0psi, I checked it at work with a controlled source and it was fine.

The article which I can scan and email for people states that the 1.5L DOHC excel engine picked up 37% more power for fitting a second throttle body to the other end of the MPI manifold. It definitely makes sense. 2 x 60mm t'bodies are going to flow far more than one 90mm one.

Chris

mutiple tb can work on a starion but think of the manufactering cost, forget about splitting piping just run piping to a large plennem and have tbs connected to that.
I rmember a old zoom they were talking about tb that have no butifly this would be ideal but the cost of doing so is huge.

i hope this makes sense but its 1;30 and ive had quite a large night :beer

the sr20 in the GTI-r uses quad throttle bodies...bigger cooler for 170kw.. instead of the 150 in the 180/silvia

quad throttle bodies are also used in some toyota 4ag engines.... think on the 20 valve... probable just better air flow... dunno... but must have some performance increase... other wise i dunno why the companies wold of done it.. my mate has just finished buildin a 13bt with twin throttle bodies...