Modified OE throttle body

[lofty]

has anyone looked into or even had thier standard throttle body modified on thier F7P or F7R, i have a spare so i could get someone to have a stab at it reasoanlby cheaply, obviously it would need coupling with other mods keep it consistant, My thinking is, what benefit would be had where a "modified" OE TB was used on a worked head with willaims standard cams?

My theory is that the standard F7P/F7R inlet manifold flows very well as standard so the improvments need to be made on the fueling side? as its the limiting factor?

 

[BenR]

you got that TB and std inlet mate?

pass it over and ill have a gander, study.......see what can be done.

but i dont expect too much.

 

[lofty]

yes i got it all, are you interested i can leave it with you for a while?

 

[BenR]

yup would be fine mate

 

[Matbrown]

Cool,

Let me know the results.



Mat.

 

[BenR]

i wouldnt expect too much, unless i can check the spindle bearing and look how much space there is for a larger throttle plate.......at most, all we can do it tidy the std unit up a bit.......

 

[maciek]

larger throttle plate in OE Tbody...?

no way
I had the same idea, and i just studied mine, and You can shave about 1,5mm dia. - at MOST. but the limiting factor is on the top of bigger flap - theres about 1,5 mm between it and the small one. and intake side to the Tbody, where You would not shve more than 1mm dia. - I thing its pointless, and too much fuss.

 

[BenR]

which is why i was saying not to expect much. But increasing the diameter on the bog one by 1.5mm will yeild more than 1.5 on the smaller one.

Then we can get fancy and offset the spindles?

alot of work yes, but work is fun!!!!!

just wait till i get it and ill try do some pics and sketches....

 

[BUTRE]

GO TBs GO GO GO !!!

 

[BenR]

yeah, ok!!

all i need you to do is mail them to my address and ill whack them on.

 

[Simon]

I got hold of a std. inlet manifold and throttle body for the 172 and took it to a well respected company. Guy there said there wasnt enough meat on the body or manifold to warrant enlarging. Although if I was racing it on the track then another approach could be taken.

In the end the butterfly has been modified to improve flow. The std butterfly is 3mm thick !!

 

[BenR]

well, ill just wait to have a look first before i come to a conclusion.

 

[Simon]

BenR,

Any chance you can post a photo of the 16v inlet manifold ports and if you have time measure the size of them and distance between each. Im still wondering if the 172 inlet manifold would fit a valver. The plenum chamber on the 172 is quite large - 4.8 litres to be exact and if it went on with the throttle body should give a good gain.

 

[BenR]

but you have a 172? lol

anyway, teh easiest thing to do is to go to Ren......get them to seach for the 172 manifold gasket and the 16V gasket...and when they come compare them.

then say "oops...my mistake mate, totally wrong part"

 

[Simon]

Ive got the 172 gasket. Ill just go in and get the 16v one. They think im mad anyway as im always asking them questions out of the ordinary.

 

[BenR]

lol......

wait till they give it a service, they wont know whats up! haha

and whos 16V are you putting it on? yours? eventhought you dont have one...it seems...lol

 

[BUTRE]

ya... didnt have a camera when I asked at renault if the J7R turbo would fit a clio! eheh that shocked the guy giving me more attention on valver and willy spares.

GO TBs GO GO GO !!!

 

[maciek]

One beer for me plz.

 

[maciek]

BenR:
only in the back - manifold side there is more metal, as you see. on the intake side there on the whole lenght - until the back end, the thin "egg" line visible in the first pic. is maintained, so theres really almost nothing there.

 

[BenR]

how very true.......

and may i add, you have a VERY clean TB!! lol

Again, i will still like to look at one in my hand....

 

[maciek]

I have bought a spare engine with leaking block, so I took all the bits, and bobs out, and started to preparing them for upcoming engine work. So I begun cleaning the TB. I will maybe try to smooth the rod and something with the flaps - what do you think? what can be done?

another pi
c;

 

[BenR]

Dont know, i have NOT seen one yet....lol

you can obviouslt do some to the spindle and plate......

which one opens first, the small one?

maybe we could use a lazer cut base and fabricate our own TB?

I dont know, ill think about it.......looks limited though.

 

[Simon]

So am I correct in saying that the 16v Throttle body has two butterflys - a small one and a larger one?

What are the designs reasons for this? Does the small one open at lower RPM giving better torque and then the larger one open up at higher RPM?

Excuse my ignorance.

 

[Simon]

Looks like the butterflys could benefit from being slimmed down at the edges to improve flow.

 

[BenR]

There is a bit of detailing that can be done.

The reason for 2 is control.

When you have a butterfly, i can only open the 180 degrees to get max flow. The larger the diameter the larger the propotiante increase in flow per each degree opened.

So, for a 5 deg opening, a 50mm butterfly will flow alot more than a 15mm butterfly.

So, a small one allows more accurate control of part throttle operation, making a smoother drive.

Also, due to the shape, twin pates allow better use of the available area.....

 

[maciek]

Yes. small one opens first. the big one starts to open when the small is around 45 deg.