I put on my Lonewolf intake, and 90mm TB

[WizardBlack]

I'm sure if they got an edge by using a larger body, they would have made one.

 

Maybe so, maybe not. Perhaps they looked back at another car that used a 60mm throttle, etc. and thought the same thing. I cannot give you a direct before/after comparison and I don't think digging out a fluid dynamics book would be useful; just that it's done all the time as a part of a collection of modifications. Personally, the WOT thing is what convinces me. I look at the car on boost and consider the air flowing through the system like a liquid. You want a nice smooth flow and even tapers in diameter from the compressor outward.

WRC cars make a lot with a restrictor, but they'd probably make a lot more without it, obviously. Otherwise, the rules would not dictate one.

Ultimately, if you're stuck on that one car, that's fine. I'd say there are plenty more cars making big power with one.

 

So anyways, any updates?

[Tony D]

Restrictors go before the turbo. The VG30DETT made 1100HP without the IMSA required 26mm restrictors on the turbo inlets. They had a bigger T/B, but as far as I know E-Motive was not running in a restrictor plate series at the time... I never said the E-Motive car had a 60mm TB, I simply stated it was sure smaller that the 90 mm unit being used. I could scale a photo or someting to figure it out. I would suspect something along the size of their turbo piping was used, if not slightly larger for a "WOT No Restriction" flow scenario.

 

If there is a restrictor before the turbo, maybe there is some logic for it (going appreciably larger than normally seen)? I recall the #75 IMSA car had a decent sized body (single). But the driver of the car said the car was more driveable with the restrictors as it gave them more useable torque down low than the unrestricted engine(Steve Millen).

 

For the time they were doing the development on the E-Motive car, they went though a lot of development---they may have taken an idea, or two... but I believe they were independent enough to let dyno results rule the decisions they made and not 'go with the flow'... They DID run twin turbos in 81, and ditched that idea pretty quickly (especially after the fire...)

 

Come to think of it, outside Drag Racing... which nobody specifically stated was the purpose of the build, I don't know that a lot of 'roadrace' cars have humongo TB's... Decent sized, maybe...but not absolutely huge. I will have to do some investigation there, that sounds like an interesting study to do.

 

I know Drag Cars have big stuff, and it may indeed be someone simply misapplying the technology because it 'looks cool' and like Millen Mentioned makes a peak power number, but at the expense of power under the curve.

 

I can see in practical terms up to probably 75mm. That would be the largest practicable pipe you would use for about any horsepower level in these engines. But 90? That's what 3.5" or something like that?

 

Bulges "up" in size will also affect flow without the proper taper lead and exit...

[stagefumer11]

I think the best thing is.. Where is phill.. Ive been waiting for update for along time

[Tony D]

I think the best thing is.. Where is phill.. Ive been waiting for update for along time

 

WOAH THERE!

 

This is not a 'best' discussion. Nobody has told me an answer to the question I posed, other than cosmetics or theoretical nebulosity. I stated outright I did not know just that it seems to me if E-Motive got 1000hp out of that engine, then I really wonder WHY that huge TB is there. Do you really need it. I have already stated that if there is someone who wants it there, that's fine by me. But if someone is stating factually, or implying that it in somehow is better suited than a smaller TB---I would like to know why.

 

Best is determined by the use of the machine, and it's application. As I stated, maybe this is a Drag Race Part, and in that realm it is properly aplplied. Similarly, when its applied (say like an 1100 Holley Dominator) onto a roadrace or street application of half the horsepower....is it helping or harming that application?

 

Maybe Phil is DOING something. If he's up on the dyno, it would seem it would be easy enough with that intake to prefab several adapter plates and put a Q45, 75mm, 70mm, 65mm, 60mm, 55mm, and 50mm TB on there with a dedicated intercooler return pipe to do back-to-back comparos for which setup INDEED would be "Best for Phil"---and damned interesting to boot. If I had the time, I'd swing by the dyno and assist, hell, even chip in some money for the Dyno Time such is my interest in this particular subject.

 

Understand, I have to build an engine to run at Bonneville... Anything that will get me significant WOT HP will be of interest to me. It will be a highly purpose-built motor, so I'm not worried about Tip-In or that kind of modulation crap. What I need I can make out of a nautilis linkage, no problem.

 

But if I find I make significantly more torque which will allow me to accelerate through the gears quicker, and assist me when pulling wider spreads...all by using something smaller than a Q45 body, or something Humongo, then I have to defer to the functional demands of the setup.

 

I'm asking why, and thusfar there really hasn't been 'I tried this on the dyno and found' kind of an answer, nor has any real convincing evidence been proffered as to why 'bigger is better' after a given diameter or horsepower level.

 

As it is, I will likely have to build the intake...oh waitaminit, we're not using a single air door... or will we? That all remains to be determined!

 

Remember, the GT-R comes with triple style butterflies, and these guys change to a big single... There's no way the 6 opened 45mm butterflies are anywhere near the cross sectional area of the single. At least not by looking at it. Most of these 'big body' RB plenums are actually a step down in size from the flow potential of the existing butterflies. Which reinforces my question 'why are these guys downsizing the throttle area'?

[Roostmonkey]

I'm thinking air speeds.

[Tony D]

As MonZster's little experimentation in CFD showed us, big for transmission seems to be good, but remembering the HKS Plenum, it didn't seemed too hindered by the 'small' holes to transfer the air to the plenum. The nexking points seemed to be more in the delivery piping being too small, rather than the entrances to the plenum being too small.

 

Really, the last thing you want in a plenum is velocity, you want diffused pressure equally applied down all runners.

 

Which is why I'm thinking about that smaller T/B, through the body it is fast (possible pressure drop) but afterwards it can diffuse out and slow down. That action builds even pressure in a plenum.

 

Hey, who had that CFD? That should give us a good idea! (Back to Expense Reports)

[Canadianz]

Correct me if Im wrong, and this is just based on area calculations, If the RB26dett had 6 butterflys, then each one caters to an individual cylinder. Therefore during each intake stroke the cylinder has roughly 1590 square mm's to play with(3.14x22.5 squared). With a 90mm TB you have a much greater area, however it is divided by two, as you have two cylinders drawing air at once (3.14x45 squared divided by 2). It comes out to roughly 3150 mm square per cylinder. So just on area, a 90mm has twice the surface area even if being utilized by two cylinders at once (during intake).

 

So that being said yes a 90mm throttle body will flow a ton more than a set of 45mm butterflys, I think we are on the same page there. I don't know how to do further calculations for the actual flow of the TB's but Im pretty sure its non linear as the area goes up making the difference larger. Now Im not sure what happens when the flow is pressurized as in a turbo application if velocity is affected or what, Ill leave that up to someone who knows.

 

All that being said, one point we should lay to rest is that the 90mm TB's are undriveable, this is nonsense. I have stated before that there is no loss in drivablitly and I stand by it. My mother can drive the car no problems and she is used to a diesel Jetta. So this point can be buried, if you want to run a big TB, do it, it will not cause the car to become an on off, it will be different but as far as overall drivabilty no, it won't become an on off.

 

My second point is more one of curiosity, why is it that the 90mm topic is such a taboo or "evil" subject, every time it comes up someone posts "well I saw this vehicle make xxx amount of hp with a smaller throttle body". Which is true! However if we went by that logic, we would be arguing alot of other projects on here too. Monzter's amazing Cad research on intakes if we were consistent it too should have been shot down on accounts of the Jeff P argument earlier in the thread " I made 650 hp on the stock manifold etc . . ."

 

Nobody gets all upset when a member puts twice pipes on their older Z which again is over kill and has no practical use on a NA Z if we are going by flow numbers. I mean why does a na L series pushing 150 hp need 2.5 inch exhausts time two !?

 

If we all went by the overkill argument theory we should be spending more time on the dyno tuning every drop of our existing set ups than even modding our cars, as any spare bit of "excess" would be wastage or bling by this argument. We would have to change the site name to "MinimalistZ" !! What I would like to see is consistency, if 90mm TB's are so outrageous how come other engineering blunders on this site don't get the same treatment ?

 

Back on track I would be very interested to see the research and dyno plots concerning TB size and the effect on the performance of the engine, if there was a huge difference I would be the first to switch to a smaller one. Until there is some sort of research as mentioned above, I have no reason to switch, it drives fine, fits well and I like it.

 

 

Cheers

 

Chris

[Canadianz]

Just thinking out loud, if a Q45 displaces 4.5 liters per full firing sequence at one bar, and the L series 2.8l at one bar, doesn't that mean that a boosted L series has a much similar air demand as the q45 for example 2.8 l x 1.5 bar ( 22 psi) = 4.2l ? This is assuming A Im somewhat on the right track and two the boys at nissan did use a 90mm TB on the q45 for a reason...

 

I think I might be getting mixed up I was using some of the really simple compressor calculations we use in commercial diving.

[bradyzq]

Correct me if Im wrong, and this is just based on area calculations, If the RB26dett had 6 butterflys, then each one caters to an individual cylinder. Therefore during each intake stroke the cylinder has roughly 1590 square mm's to play with(3.14x22.5 squared). With a 90mm TB you have a much greater area, however it is divided by two, as you have two cylinders drawing air at once (3.14x45 squared divided by 2). It comes out to roughly 3150 mm square per cylinder. So just on area, a 90mm has twice the surface area even if being utilized by two cylinders at once (during intake).

 

So that being said yes a 90mm throttle body will flow a ton more than a set of 45mm butterflys.

 

Hmm, I don't agree. Why are you suggesting that the 90mm single TB feeds only 2 cylinders? It is a 6 cylinder engine. Yes, assuming 240degrees of duration on the intake lobes, since the cylinders are phased 120degrees apart, I suppose you could say that 2 cylinders are breathing in at any given moment. But that doesn't seem realistic to me. Especially as the revs rise and the time between strokes decreases.

 

6 45mm diameter circles have 50% more total area than 1 90mm diameter circle, not 50% less.

 

One more question though:

 

If the intake pipe is 90mm in diameter, and the intake runners are 45mm in diameter, assuming negligible flow disruption from the throttle plates themselves at WOT, does it really matter where and how many throttle plates there are at WOT?

[bradyzq]

Just thinking out loud, if a Q45 displaces 4.5 liters per full firing sequence at one bar, and the L series 2.8l at one bar, doesn't that mean that a boosted L series has a much similar air demand as the q45 for example 2.8 l x 1.5 bar ( 22 psi) = 4.2l ? This is assuming A Im somewhat on the right track and two the boys at nissan did use a 90mm TB on the q45 for a reason...

 

I think I might be getting mixed up I was using some of the really simple compressor calculations we use in commercial diving.

 

Me again.

 

You're on the right track but a 2.8L at 22psi is running at 2.5bar if your NA Q45 example is at 1bar. You need to use absolute pressure here (1.5bar boost + 1bar atmospheric pressure). 1.5bar would be 7.4ish psi.

 

So, assuming absolutely perfect compression of the air by the turbo and intercooler (no heat added and no pressure lost), that boosted 2.8 would ingest air like a 7L NA motor, not a 4.2L.

[stagefumer11]

WOAH THERE!

 

This is not a 'best' discussion. Nobody has told me an answer to the question I posed, other than cosmetics or theoretical nebulosity. I stated outright I did not know just that it seems to me if E-Motive got 1000hp out of that engine, then I really wonder WHY that huge TB is there. Do you really need it. I have already stated that if there is someone who wants it there, that's fine by me. But if someone is stating factually, or implying that it in somehow is better suited than a smaller TB---I would like to know why.

 

Best is determined by the use of the machine, and it's application. As I stated, maybe this is a Drag Race Part, and in that realm it is properly aplplied. Similarly, when its applied (say like an 1100 Holley Dominator) onto a roadrace or street application of half the horsepower....is it helping or harming that application?

 

Maybe Phil is DOING something. If he's up on the dyno, it would seem it would be easy enough with that intake to prefab several adapter plates and put a Q45, 75mm, 70mm, 65mm, 60mm, 55mm, and 50mm TB on there with a dedicated intercooler return pipe to do back-to-back comparos for which setup INDEED would be "Best for Phil"---and damned interesting to boot. If I had the time, I'd swing by the dyno and assist, hell, even chip in some money for the Dyno Time such is my interest in this particular subject.

 

Understand, I have to build an engine to run at Bonneville... Anything that will get me significant WOT HP will be of interest to me. It will be a highly purpose-built motor, so I'm not worried about Tip-In or that kind of modulation crap. What I need I can make out of a nautilis linkage, no problem.

 

But if I find I make significantly more torque which will allow me to accelerate through the gears quicker, and assist me when pulling wider spreads...all by using something smaller than a Q45 body, or something Humongo, then I have to defer to the functional demands of the setup.

 

I'm asking why, and thusfar there really hasn't been 'I tried this on the dyno and found' kind of an answer, nor has any real convincing evidence been proffered as to why 'bigger is better' after a given diameter or horsepower level.

 

As it is, I will likely have to build the intake...oh waitaminit, we're not using a single air door... or will we? That all remains to be determined!

 

Remember, the GT-R comes with triple style butterflies, and these guys change to a big single... There's no way the 6 opened 45mm butterflies are anywhere near the cross sectional area of the single. At least not by looking at it. Most of these 'big body' RB plenums are actually a step down in size from the flow potential of the existing butterflies. Which reinforces my question 'why are these guys downsizing the throttle area'?

 

Sorry tony, I think i typed that out incorectly. .. I was merely waiting for a update from Phill...

[hoov100]

subscribed!

[Bernardd]

I'm sure he'll post a youtube link to his findings/feelings/data. lol

[BRAAP]

This thread on Huge-by-large throttle bodies on small engines comes to mind here...

 

 

Click me. Big Throttle bodies.. WHY?!?!?!?

[Canadianz]

Hey Brady,

 

The pressures were all done in gauge, that is usually how they are discussed, nobody talks that their NA engine is running at one bar without a turbo !! This is why the I used Bar-gauge not Bar-Absolute.

 

When you run the triple carbs you essentially have an ITB per cylinder, therefore each cylinder is using the 45mm plate all to itself. So in order to compare I would have to use somthing relative such as when the L-6 is on the intake stroke, so two cylinders are filling, not all 6 ( though that would be amusing ....once). That is what I was thinking. All the air the engine will ever get has to pass through the 90mm, as opposed to each 45mm. Even if its spinning to 10-million rpm, it will be filling only two cylinders at once, assuming its using the standard straight 6 firing order...

 

Oh and Braap your totally correct, I'm trying to think a little harder about what Im saying in this discussion. (I remember a certain speedboat coming up as an example )

 

Back to the same argument Tony is using, nobody has given a good reason as to why there is a crusade against large throttlebodies and not other forms of mis-engineering ?

 

 

Cheers

 

Chris

[big-phil]

sorry have not been on. The 90mm TB is over kill, so is the 3" IC pipe, and 4" exhaust. Drivability of the car is no problem at all. The Infinity 90mm TB has the linier action, its really smooth. But boost still creeps so I cant rev the car out past 6500 rpm without boost climbing. So my plan is to buy a BIG wastegate and mount it on my other header in a better spot.

 

Here is a video of the port

 

here is a video of me leaving a car show 11-27-09. I'm at 6:00 min into the video. So you get a little idea of drivability

 

The car feels VERY good but i wont take it to the dyno untill I get a bigger wastegaste setup installed, or mount my 38mm in a better spot??

[slownrusty]

Baby blue Gallardo pwned for showing off!

[stagefumer11]

definitely interesting the whole throttle body thing, Makes me wounder if im going backwards, since im running a 80mm unit .

 

 

Would i be better off. adapting a smaller 60mm unit ?

[spork]

One thing I've always made very clear when customers ask about what size TB they should run, is that bigger isn't always better. This usually gets into discussions about my car (running a 60mm 240sx TB) and making around 600hp or (insert name here)'s car and how it works great with a large TB. Ultimately in the end, some guys either just want the big TB or I get them talked down to a more manageable size. On a side note, if this is the intake I'm thinking, it was very custom setup that has bigger runners than anything we have ever done before. We were sent a tracing of the port layout on the head after port work was already done and then asked to make an intake fit the head. Then that particular project fell through and everything was sold off (including the intake).

It looks like Big-phil is getting everything sorted out to fit his car, but I hope the extremely large runners don't cause issues with port velocity in his particular set up.

[big-phil]

One thing I've always made very clear when customers ask about what size TB they should run, is that bigger isn't always better. This usually gets into discussions about my car (running a 60mm 240sx TB) and making around 600hp or (insert name here)'s car and how it works great with a large TB. Ultimately in the end, some guys either just want the big TB or I get them talked down to a more manageable size. On a side note, if this is the intake I'm thinking, it was very custom setup that has bigger runners than anything we have ever done before. We were sent a tracing of the port layout on the head after port work was already done and then asked to make an intake fit the head. Then that particular project fell through and everything was sold off (including the intake).

It looks like Big-phil is getting everything sorted out to fit his car, but I hope the extremely large runners don't cause issues with port velocity in his particular set up.

How would I know if im having port velocity trouble? It runs great, pulls so hard, turbo still hits in the same rpm range.