Single Throttlebody Conversion

[weejimmy]

Ive been taking out my double throtle and looking at the inlet, the single botom hole provides air to 2 intake pipes and the top 2 provide air to 2 intake pipes too,
shurley there could be some gains by replacing the 3 buterfly set up in the tb with 1 large one ,i presume the top 2 buterflys stay closed on light throttle for botom end torque on standard set up, so would expect to loose some botom end torque and responce,
has this been done? and with what results?
if i was to do this what size tb would i be looking at 90mm ish?
(i have large street port and t78 turbo).
 
or would this be a stupid way to go.

[BlitzBoy]

Really Interesting question you pose, I dont think it would be needed or much gained on mid sized single turbo setup, even on Dragons high powered FD that was still running the traditional 3 butterfly setup. Reworx\'s old drag car did run a big single butterfly throttle setup but that cost big bucks.
So unless you are building an out and out drag car dont bother IMO.
Would Luv to here the other high power rotary guys on this forum chime in on this thread.

[weejimmy]

I know what you mean but any amount of air can be flown threw any inlet mainifold if the boost is high enough.
i would prefer to not raise boost so just looking for that few extra horses other places.
and id quite like to build a new inlet anyway.
there is 80mm throttle bodys on fleabay for £100 and the fab work would cost me £50 max for materials (and the labour is free) so not crazzy money (even if i do end up with a shiny inleted laggy car with no more power lol)

[BlitzBoy]

well if your quite adept a fab work Id say go for it. What I would do first is dyno the car, then once you have made the changes redyno it and see if you have gained or lost anything on the power curve

[AtomicRex]

I spoke to Carl about this....his opinion is there is no need to remove.

However I think TonyC has done it

[BlitzBoy]

Removing the double throttle was one of my first ever mods, its only used on warm up to stop full boost. Removing clears up the inlet tract so at high rpm air flow characteristics will be better. Personally found it pulled sightly harder after removal.
But lets get back to the main title of the thread , who else has done a custom big single butterfly conversion?

[weejimmy]

well my cars not run in yet after being to pips so itll go down for final map and get my dyno figgures from there,
then if i do it i can re dyno and see the difrence, can always stick old one back on if it dosent work out.
Is tonyc on here?

[ianelvar]

Have you worked out how big a single would need to be to equal the area of the three?

The area of the stock TB is:
45mm each butterfly
area=45*Pi*3

= 427sq mm

Compare that to a 90mm single TB

area=90*3.142

= 283 sq mm

No comparison really. The Mazda TB is a lovely piece of very subtle design. Don\'t be fooled into thinking it\'s a restriction point, it\'s really not. Compare it to the dimensions of the ports, for example.
The way that the lower one opens before the other two move is also quite crucial in making it driveable. If they all opened at the same time you\'d have something approaching a digital throttle.
I do agree that there\'s possibly some mileage in removing the double throttle though.
I\'d hate to see you go to all that work only to find it\'s not as good as the stock setup.

[shaunwil]

Area is radius squared times Pi .

so the stock throttle bodies are 4771.9125mm2 and a 80mm is 5027mm2.

I run a single on the 1st gen and you do loose some of the bottom down control. Good fun in traffic. Plus the stock throttle body has quite a large travel (if its like the fb) and the throttle pedal movement is alot less and between closed and open. Pedal travel halved with my throttle.
The stock throttle doesn\'t always open all of the ports.

Plus you need to worry about the location of the TPS on the new throttle body and if it will fit ok.

Best bet is to look on USA ebay, there are plenty of V8 ones.

I need at least an 80mm on the 1st gen to get average power, but its N/A. I think i\'ve got a 65mm one at the min but its too small.

Shaun

[weejimmy]

i see your points but most cars have a single tb and dont suffer from poor drivability.
i was thinking as i have larger than standard ports i should have larger than standard diameter inlet pipes and tb.
I was just guestamating at 90mm.
 
a well nothing wrong with a bit of trial and error. (i hope)lol

[shaunwil]

Mines running on a carb and the LPG carb was a single inlet. Don\'t know if EFI single throttle is easier. Think half of it is all ports are open all the time too !

Please remember most cars only have tiny throttle bodys :Giggle

Shaun

[TonyC]

I spoke to Carl about this....his opinion is there is no need to remove.

However I think TonyC has done it

Slight difference Jon, I simply removed the extra butterflys from the upper inlet, but weejimmy is talking about the butterflys in the throttle body and making a new throttelbody with a single butterfly. Would probably have some effect on WOT, but make the car pretty undrivable in most other circumstances I\'d imagine.

[weejimmy]

well ive got my interccoler today so got plenty work trying to v mount it to get on with,
mayby reserect this thred in future.

[interloper393]

just go with a custom plen n lim.. but keep the standard tb O n let me know how it goes cus i like the sounds of it lol

[weejimmy]

ok as i said need to sort v mount out then run car in, get set up at pips then start playing agin,
i was thinking
1 dyno figures
2 tubular mainifold with standard tb - dyno
3 single tb - dyno
4 whatever was best - boogy