Dude, has been mentioned that having a different top to bottom (ie - chopping out half the shaft for greater airflow profile) may actually lead to more turbulence throughout the airflow from that point on. Which could be true... How do you reckon you'd get on with leaving both sides of the shaft on with your engineering?




Still waiting on getting me car back and finding a super dooper temperature sensor before I go and put this phelonic spacer in and provide some real information on heat patterns. The grill over the holes in the bonnets get so hot you can hardly leave your hand on them without leaving a stripey pattern on your arm, so guess the bonnet chop is working as desired (just looks damn ugly....)

imo with or without turbulance its still a gain in rwkw from the std throttle body.
so i dont think a tiny amount of turbulance from the throttle shaft is going to make a difference..lol

Yeahp, that's what I am hoping for.... My theory on this is developing as I speak (and will, no doubt change by the time I finish typing it...)

It goes along the lines of cylinders number 1 and 6 are further from the throttle and therefore work more to pull air in.

As we know already, air is less dense when it is being sucked.. Therefore a compression of 1:9 will only really compress air eight times (let's say) over air pressure, not 9 times as would be expected. Basically- wherever something is sucking, there's a vacuum that is being filled as fast as possible by incoming air....

-=SIDE NOTE=-
This leads me to my theory on extractors and exhausts... The age old theory about "back pressure" being essential for a well running four stroke is, in fact, total crap. The reason why you need some restriction in the region of the first metre of pipe isn't BACK PRESSURE at all. Do you know how fast the bloody gases are moving out of the chamber? Mate - put ya foot down to 5000 rpm in neutral and get someone to put a balloon over the pipe. The whole thing about "back pressure" looses itself right there...
***What is happening (in my humble, novice and unlearnt opinion) is that the gases are moving FASTER through a slightly constrictive pipe and therefore have their own momentum which leaves a vacuum behind when the outlet port is shut - thus, when the port is open again, there is a small vacuum already present which SUCKS the combusted material out of the cylinder.

Go on, tell me I'm wrong so far.

If you put 3" pipe out of each port from your engine head, you'd find the bloody car would perform like rubbish. Actually - just pull the headers or extractors off entirely and see what happens. It's crap! It doesn't work! The fastest big a*** motors have straight headers sticking out that are just long enough for the gas to reach the end as the next load comes in behind it.... Look at top fuel dragsters and the like.....


This, in turn, leads me to look at PACEMAKER extractors with interest. Do the best extractors go 6 into 3 into 1... And why? The fastest flowing extractors at low revs may actually be 6 into 2 into 1 as the exhaust ports are opening and closing in a manner that enhances the "pull" effect that people have been labeling "back pressure" for too long.

The 6 into 3 into 1 is interesting in the sense that you could argue for putting different cylinders in line with each other. 1,6 -- 2,5 -- 3,4 seem like good choices as they are moving together, on opposing strokes. When ONE is up and firing fresh gas, SIX is up on it's exhaust stroke. At low revs this may not be enough for it to actually start sucking the gases out all by itself... It'll sound awesome, but is it working as intended?

How about (and I'm sure people do, and have, and even own this..)
How about having the pipes arranged so that one pipe fires, then the next - Say numbers 1 & 5 connected. Or even 1 & 2. That way you get a pulse and then another pulse and then a longer pause.

This may achieve a large vacuum behind the two pulses which creates even more suck for the next cycle... Or, it may just create back pressure


GAWD, I do go on........

-=< END SIDE NOTE >=-



Where was I? What thread is this? Wasn't I abusing some idiot about something which I had nothing to do with?


OKAY -

The air coming in through the throttle (in this case, 25% more than standard) would be travelling at a slower speed for the same amount of revs. It would be doing the same speed through the pod (or through the panel filter if your that way inclined) but it would be traveling down the throttle body slower.

This should mean that it can turn the corner and head on out to the mighty far reaches that air calls "a pain in the a***" and we call cylinders 1 & 6.

Cylinders 3 & 4, being right under the throttle, would appear to have an easy go of it. Thing is, they are kind of slowed up a bit on their efforts by their air being robbed by the weezing 1 & 6. Therefore there is a vacuum. Therefore more air is sucking in. Therefore there is more turbulence as the air is moving faster and must go through these complex curves and directional changes to get out to the further reaches of its known universe - 1 & 6.

This isn't all just total theory. I have pulled apart a few BBMs, and have learnt nothing over what I did pulling apart one. Not only do they look similar on the outside --- They're all similar on the inside too!


I have (once corrected by FAST XR about my s**t maths) worked out approx rates of air use etc etc and found the standard throttle body should work just fine for N/A setups.

But then - If you were to put (let's say) two 38mm throttles between cylinders 1-2 and 5-6 you'd probably find a similar gain to a huge single throttle body. If you put six (let's say) 38mm throttles above each cylinder I'd say you'd have the most efficient intake of all time. By the way --- The ports into the combustion chamber are about 38mm (if you're lucky not to have a miss-matched head and manifold and / or gasket sticking in the way) so I choose 38mm with the idea that the throttle is then wide open at the same width as the cylinder can suck in. Therefore each cylinder can get at as much as it needs, when it needs it. Interestingly (to me) each chamber in our I6 4.0L's has a displacement of 0.666 L... Therefore at something like 5,000rpm each cylinder requires a fair heap of air....

As for putting multiple throttle bodies on... Why don't they do this?
Why do they now use coils at the plug by the way?


Bugger me - where was I?

Oh yeah -
The larger TB with it's slower moving, more dense air, should do a better job of providing that air to all the nooks and crannies that is the inside of the BBM, without the need for super fast flowing turbulent air and all that it entails.


The idea of having the pin the same on both sides to prevent an "aeroplane wing" pressure zone inside the throttle could be taken further too.




Maybe the REAR of the butterfly opening should be sharpened, not the leading edge?



Maybe butterflies have been designed stupidly all these years... Maybe they should have been curved so that when they are a third (or even a half) open the top edge is facing back into the BBM and thus providing a smooth air flow with less turbulence.





It has also been said that turbulence would stop the fuel from vaporising and being burnt properly. My quick thoughts on that is all to do with how clean are your injectors, and are the firing a pattern or a cheap squirt? Tubulence may even help it spread evenly around a combustion chamber.


If anyone ever feels like putting heaps of holes in a BBM and using a very sensitive pressure gauge I'd be very keen to see if this holds water.



As it is now 1.30AM in Kiwi land and I should hit shutdown on the old gray matter, I will be back to have a re-read and see if this makes sense some other time.

i do sharpen the rear edge, just not to the same degree as the leading edge, but i can make them the same no problems...

Mate, I am sold on the idea already - but to be honest I have not found the two throttle bodies I owe you yet! They were in my mates garage a month ago, but someone may have used them on top of a Cefiro or something. The garage is a right royal state with crap everywhere. It's complicated to even get in the door, never mind find anything that you have not seen for more than a couple of days. Hopefully find them this weekend...

I am sold on the idea already. Not simply because it's bigger, but for all the reasons laid out above - the slower moving air produced by a larger opening will have less difficulty finding it's way around the complexities of the BBM and fill the far reaches of the BBM with less stress for everything concerned.


I also note that "increased throttle response" may just be because more air is getting through the new TB opening at the same throttle position as the old TB opening...


Sharpening the edges is something that is perfect in a perfect world and I'm impressed that you're doing it at all, never mind both edges. Hell- I'd be pretty happy with you just taking the burs off the damn thing to be honest.

I also happen to think that the aeroplane wing idea is a non starter.... There are a couple of reasons, but the main one is simply that it only comes into play at WIDE OPEN THROTTLE and at W.O.T your larger TB will still allow more air into BBM easily than the smaller standard one.


Right. Is pissing down here, I still have no car (yawn.....) and should go down the garage and look for TB's for you, along with make some MAL WOOD clutch pin style attachments and finish the firewall strengthening devices......

It is raining tho. Might just go back to bed.



Yours sincerely,


Fiend
He of the mammoth post

This is very interesting im hanging out 2 see more dyno sheets... my motor would probably love this though...

yep would be more interesting to see before & after dyno runs within 30 minutes of each other, as oppsosed to months apart.

even back to back dyno runs can vary by a few kw ive found.

yes they can vary but the line is much the same, its obvious when one line dies off and the other keeps rising... and not just natural variation

if i have time ill drop into CMS this afternoon and pick up some print outs...

there usualy isn't 9rwkw difference. 2~rwkw difference i had when i did 4 runs.

pffft on ebay they claim 15rwkW hahaha!

Yeah, you gotta watch those E-Bay sellers and their claims of this and that. People do buy the stuff, but they're probably not people who are willing to prove it on a dyno.

OK. I did notice a differance in power but not 15rwkw. I think no more than 5rwkw will be a more realistic figure. I take no short cuts when i do things, do it properly the first time or don't do it at all is my motto. The way i see it is a few kw her & there all adds up at the end.
The dust coat wearer talking about turbulance in throttle bodies & manifolds get a life. We are driving street cars not v8 super cars. You will send so much money & time to notice no differance in a street car.

I also believe that chassis dyno's are not a true figure it is just for tuning cars. The only true way is a 1/4 mile not time but MPH or KPH. I have seen engine & chassis dynos vary from dyno to dyno with the same car & same engine in my time of racing.
I say mph or kph because a times can vary with wheel spin, gear changes etc. but at the end of the stip the speed will be the same providing that full throttle & rpm is on.

Your talking about a couple mm increase in throttle body size, that in itself is a 'minor' detail, so eveyrthing has an effect on the outcome

to sit there and say "its bigger, it works, wow what a difference, id say it measures 5kw on my a*** dyno, everyone go out and buy one"..... doesnt really make any concrete claims

i found this quote interesting, please dont bother with stupid replies, but rather discuss what looks to make more sense than what ive seen so far

Hi there ---

First time anyone has ever called me a "dust coat wearer" and I am yet to decide if that is a good thing or a bad thing. Obviously wearing such a coat would help keep my three foot dreadlocks from leaving oily marks on my suit jacket for my dinner engagement later tonight. Maybe I should look at investing.

As far as I am concerned racer boy, I know I am a novice. As such I am not prepared to simply believe quoted figures for no reason and I look to find the reasons as to why this works (or if it doesn't work... Or even - how to improve things).

This is the same pholosophy that drives new and improved variations of old products --- This 68mm throttle body being an example.


FORDMONT BROTHER... Did you have a quote there about turbulence in the BBM as well as the above example by any chance?


RACER - You will note that my name is on the list for one of these items as I do believe it will work. I don't believe it works simply because it's BIGGER, but because of the inherent qualities being BIGGER produces. Particularly with forced induction, should work well...

I think I've worked it out well enough that when combining this with some nice extractors, a free flowing air intake and a cooler BBM that my tired old 330,000km stock EF motor will love me.

Rather than just put bigger expensive bits all over the car, I'd prefer to f**k around with it a little and properly form an opinion based on real world problems and answers.


I note you talk all complicated and complex about DYNO figures. You're saying all these little things can change a dyno score, yet you don't seem to give a flying toss about how things work.

By understanding how they work you can then modify and tune to your hearts content....

(Which, to you, would mean a bit shaved off your quarter mile time)


Like I said, never been called anything like that before and am still tossing up the pros and cons of the whole thing.

Just how do you go about making your car faster Racer? Do you simply go to someone who cares about how things work and pay them? If so, go and get them to discuss it all with me, and then they can simply tell you "yes" or "no" in relation to if you should buy one.

I think you should, but you'll have to work out why you should for yourself.

(Although, yes, you already have a similar item bought from E-Bay with a claimed 15kw gain... <cough> so you'll have the dyno print outs to upload for us...)

Last edited by fiend on Sat Dec 20, 2008 12:42 pm, edited 1 time in total.