7 port head and throttle body design...
Turbo Mini Forums

Right i'm thinking of bitting the bullet and buying a bare casting of a 7 port head to play with.

The plan is so i can design a manifold/throttle bodies for my design and make project next year on my BEng mechanical.

I'm thinking a throttle body would incorparate a few of my subjects and wouldnt be too hard to make. bearing in mind i will have access to any machining i need at work. Also i will have access to loads of CFD after modelling it myself on UG NX3 as a full working model.

So what do you guys think?

It would also be nice to say that i designed and made an important chunk of the car.

It will be all controlled via my emerald ecu.

Been mulling over the various different options via some searching on the t'internet.

So far:

Conventional butterfly TB's
Slide TB's
Single Roller TB's
Twin Roller TB's

Now the twin roller TB's look like they will have the best characteristics for providing a stable idle and then maximum flow at a minimum size.

I'm not going to go for bigger is better!

Something else i'll most likely consider is plenum design.

The other thing i've got to consider is single TB's of Twin TB's. I'll be making them on a DCOE pattern manifold due to that being the config of the 7 port head.

I'm thinking that a twin TB would be better in terms of manufacture etc.

The design we had drawn out (before it got binned as we had to rebuild the whole car) was just a single throttle body into a plenum. Simple and effective.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

I'm thinking that for a 7 port that an individual TB per port would be best?

Not sure though so keep them coming!

When the TB's will be basically manufactured for free (hopefully!) number isnt a problem.

Its an interesting problem and one i'm looking forward to tackling!

I've been asking people who know lots more than me, I have been adviced to go for a single TB on my 16v project.

If you think about performance road going turbo cars, (cossy, scooby etc) they all have only on TB.

Team www.sheepspeed.com Racing

I'm going single TB with my 7 port,

I was thinking maybe having the TB at the centre, a bit like an RST manifold.

Although I have to get the head back from Vmax and finish building my tig welder yet.......

I agree there but would be nice to know why.

Maybe OEM's couldnt justify the extra cost for the benefits it provided? or maybe there arent any benefits?

All interesting questions that i'm hoping to collect along the way!

BMW M3s and M5s have got one per barrel, and those aren't slouches either...

Look at any (every?) decent performance turbocharged engine and it has a single throttle plate and a plenum volume between the valve and butterfly.

Note that this approach is taken over the conventional manifold design.

I don't see that cost is an issue why they don't do it really. Nat asp motors have separate butterfly's because they flow better. Turbo engines don't need the flow, but clearly do benefit from the damping of a large plenum.

If you want to do something B-eng wise, you need to be looking a LOT further than what you proposing IMO.

Dave its only for a design and make project not my final disertation

Single sounds fine, just didnt want to go on hearsay if you get me

I wasnt denying that there arent fast cars with just one plenum, just wondered the reasons behind it preformance wise

Keep the ideas etc coming, it may be of benefit to you all later in the year if you after a specific throttle body for the job. i could literally supply just drawings to make your own type thing.

Another point, what did the old turbo'd F1 cars use? i know the current NA ones use the twin roller TB's per inlet.

only turbo'd exceptions i can think of are jap stuff, know the nissan pulsar/sunny GTI'r has individual throttle bodies and a turbo, and i believe some skylines doo too. but the throttle bodies always lead into a plenum anyways. only advantage i can see would be slightly sharper throttle response?

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

If you want to be fancy about something why not go for variable length intake runners. I think that would make much more difference than TB design.

Edited by jbelanger on 30th May, 2006.

http://www.jbperf.com/

Definately with Jean on that one... Variable intake length intake; that is a sweet idea!

Variable intake length eh.....

not giving away secrets there are you?

I remember a post from whaaaay back someone was pointing out that the intake lengths on the akm head differ in length which would be bad, and I said that it would help spread the torque range.

intake lengths on the head?

Compared to what? An A-series head? So they're what, an inch longer????

on the akm head the outer two intake tracts are longer,

theres a pick of a head in random photos, mini13's stuff, the difference is only about 1- 1"1/2.

compared to an A series head they're probably around 3-4" longer? due to the cast in manifold.

On a NA engine I think this difference in length would possibly make for a SLIGHTLY better spread of low down torque. On a turbo engine I don't think it will make a toss of difference TBH!

Not a toss of difference LOL.

i think it was a thread on minimania so it would have been N/A but I agree it'll probably make pretty much sod all difference.

yeah was defo thinking TB's to a plenum.

Interesting stuff for sure and definately worthy of a project me thinks!

Hmm may invest in a head when i get home...

RB26DET in the Skylines have individual butterflies - serious horsepower potential - high revving.

2JZGTE in the mkiv Supra have single body - again serious horsepower potential but typically lower engine speed range due to relatively long stroke.

This is my atemt. I am about to make the plenum and i am going to use a single throtle body. I Hope I will get my 7 port head in about two weeks.

If you see any problems with this design please tell. I am going to make a new one next year. So this can be the prototype.

I hope this will be on the roar this summer-

This is how the finish thing looks like. Hopefully it will work okey.

That looks gorgeous! Really neat setup. I thought the difference between single or multiple TBs was to do with manifold design rather than their number. Like multiple TBs are mounted directly on the head with no runners or plenum but singles tend to have a good plenum volume and longer runners. Know what I mean? Thats applies to NA engines though.

If am an not mistaken, Dars is putting this setup in his turboed cab :)

www.shag.no