Homemade Throttle Bodies

[Pysco]

Isnt a throttle body bascially just a carb. with all the bits removed apart from the throttle plate and a feul injector added?

So why not get a custom manifold made, keeping the injectors where they are on the standard manifold and bolting on 2 DCOE 40s or something simular with all the bit removed and the TPS attached?

Just a suggestion?

Simon.

 

[BenR]

making TB is old practice and is fairly easy, you hjust have to be a competant welder, especially if its aluminium, then its gonna be tig welded.

The easiest way of making TBs is to make you own Tb assebly direct to head, so no need for manifolds.

basically, just make a cardboard cutout of the mounting points on the inlet mfld, and then cut a stell backing plate to the same design, weld on (smoothly!!!) suitable Tb pipe, insert butterfly or roller barrel on the spindle, cut hole for injector behind butterfly and weld it in using a injector plate, or on top of the trumpet if its of the shower variety.

Bit of a simple explanation, but you get the jist, i can send you details if your interested.

 

[Pysco]

Some details would be great, thanks.
Simon.Hyson@btinternet.com

Cheers, Si.

 

[BenR]

tell me what you want to know first?
other wise itll be a 12 page affair!!

 

[coolspot007007]

i thought i heard Prima did a manifold for carbs?

 

[Pysco]

Sorry Ben,

I just been looing under the bonnet, Im I rigt in thinking that on the F7P engine the injectors and feul rail are mounted on the head and not on the manifold? If so this would make the job a lot easier as they could be left where they are, right?

What size throttles would I need and where could I get them?

Also throttles are round right, and the holes on the head are flat sided ovals arnt they? How would you make deal with this?

What would I do with the 5th injector, Idal speed control valve, TPS, crankcase hoses, etc? And what about the ECU, would I need to get a Unichip custom jobbie or simular?

And finally, what sort of power gains would I be looking at? 30bhp?

Cheers, Simon.

 

[BenR]

yup, they do TBs which use the same manifolds for carbs to cut costs down. But you must remember when using Tbs that they done need to be as large as carbs because they have no venturi. So a car runnin on 45 dcoes with a choke size of 38mm, only needs a 40mm TB.

But prima suck!!!

 

[BenR]

oh and simon....doin the carb route is laborious as you have to cover up all the progression holes, clean up teh venturi and main jet holes....basically seal them.....annoying.

and its best to use a two stage injection system...a set of injetors behind the butterfly and a set abouve the inlet trumpets for high rpm.

 

[BenR]

yuo0 would need full engine manage ment, not a piggyback system. something like emerald 3d.

the hardest part would be making the manifold, and i dont nkow about the fuel ral as i havent had a close look at one. i know the f4r has a fuel rail on the manifold. But when you replace them, basically, you just attatched all the anciliaries ot the TBs. with a potentiometer at one end. no need for the 5th injector...just program the 4 to do the same job.