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Discussion Starter #41
But your forgetting not every cylinder is taking 100% capacity of air at a time, your also not including what that spindle does air flow.

Amt allways said on a diffrent port shape they would be brilliant but on the rb26 head there not
Why am I not seeing a restriction then Dan, surely you/AMT can answer that?
 

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Why am I not seeing a restriction then Dan, surely you/AMT can answer that?
Again why you bringing amt into it are you obsessed or something matt?

I would say because you have a massive great turbo pumping it in there, and perhaps if you did run a single tb you would be able to run the same power at less boost. Not sure it would even be possible to see that power with lower boost I didnt even think what you have achieved at that boost pressure was possible
 

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Discussion Starter #43
Your also forgetting say you have a greddy plenum your still restricted by 4" inlet
My pipework is ALL 4" inlet/outlet. I'm presuming here that you cannot say the same Dan.

Did the flow calculation take the full intake/exhaust system into consideration or just the plenum and single TB?

Perhaps that's why I'm not seeing the losses as yet?
 

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My pipework is ALL 4" inlet/outlet. I'm presuming here that you cannot say the same Dan.

Did the flow calculation take the full intake/exhaust system into consideration or just the plenum and single TB?

Perhaps that's why I'm not seeing the losses as yet?

Mine isn't matt is 3" from turbo to intercooler then intercooler to plenum 3.5 inch I decided to stick with 3.5 incase I wanted to go to 90mm tb
 

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Discussion Starter #45
Again why you bringing amt into it are you obsessed or something matt?
Dan, is there some other issue you want to bring up mate?
Just put your cards on the table because I have no issues at all with AMT, if he's seen his arse and fallen out with me over a customer of his who asked me for advice, then that is his problem not mine.

For the record, it is YOU who keeps referring to amt - here are your responses regarding them in this thread alone, how can I not refer to them if you cite them as your main source of information in so many posts???

That backed up with what amt have shown in flow charts should be enough to convince any one.
You no why Matt cause the multi tbs restrict flow, amt showed every one years ago.
Rich at amt had 750bhp at the flywheel and crap old road tyres he also had 19" wheels.
That backed up with what amt showed/explained to me and hypertunes said was enough to make me decide a single tb was the way to go.
Amt allways said on a diffrent port shape they would be brilliant but on the rb26 head there not
 

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Dan, is there some other issue you want to bring up mate?
Just put your cards on the table because I have no issues at all with AMT, if he's seen his arse and fallen out with me over a customer of his who asked me for advice, then that is his problem not mine.

For the record, it is YOU who keeps referring to amt - here are your responses regarding them in this thread alone, how can I not refer to them if you cite them as your main source of information in so many posts???
Matt I was refurring to the flow chart data what was posted by blue 32 posted from amt and previous conversations I've had with amt on this subject nothing else

I'm not saying you or any one has a problem I just don't no why you said about why do I or amt think you havnt seen a restriction yet. If you want to no why amt think you havnt phone/text or email them
 

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Discussion Starter #47
Matt I was refurring to the flow chart data what was posted by blue 32 what amt sent him nothing else I can find the thread if you like?
Yeah, please do.

I'm not saying you or any one has a problem I just don't no why you said about why do I or amt think you havnt seen a restriction yet.
Dan, you constantly mention AMT and quite clearly posted "are you obsessed or something" which after mentioning them once in a response to you having mentioned them at least 5 times, I find instigating in nature.

If you want to no why amt think you havnt phone/text or email them
When I find my ITBs to be a restriction, I'll research an alternative but as yet, that's not the case. Therefore, I've had no reason to take it any further with anyone.
 

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Yeah, please do.


Dan, you constantly mention AMT and quite clearly posted "are you obsessed or something" which after mentioning them once in a response to you having mentioned them at least 5 times, I find instigating in nature.


When I find my ITBs to be a restriction, I'll research an alternative but as yet, that's not the case. Therefore, I've had no reason to take it any further with anyone.


Because the only useful information on this matter is from blue32/amt

It's because you asked a question like I can answer from amt? I'm just giving information I've been told/seen
 

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From that information and results you should gain performance from a single tb but of course maybe sacrafising progressiveness. But I suppose that's what happens when going for big power exactly the same as big cams
 

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Discussion Starter #52 (Edited)
Are those results with the same Plenum and the only change was standard ITB's to what size TB?

Edit: Looks like a comparison between with and without ITBs to me, just to show what the restriction is; i.e. not a comparison against a single TB which has it's own restrictions?
 

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Are those results with the same Plenum and the only change was standard ITB's to what size TB?

Edit: Looks like a comparison between with and without ITBs to me, just to show what the restriction is; i.e. not a comparison against a single TB which has it's own restrictions?

That was with and without I also read somewhere Amt saying a single tb lost only a couple of cfm but obv that wasn't on that test. That's just showing how restrictive the itb are. But we went through all this last time matt. I've given you all the information I no or should I say researched
 

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Are those results with the same Plenum and the only change was standard ITB's to what size TB?

Edit: Looks like a comparison between with and without ITBs to me, just to show what the restriction is; i.e. not a comparison against a single TB which has it's own restrictions?
I can see where you're coming from Matt but TB's and plenum are inextricable linked...
What I mean is that you cannot run a std plenum with a STB. You need to run an aftermarket version which will invariably be of a different design. Plenums using a STB will have longer runners (as an ITB delete if you will...).

I get that you're trying to compare JUST the ITB Vs STB without taking plenum into account but I really don't see how you can TBH....

It IS a factor...



TT
 

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Is it not that the distance from the TB to the valve is important?
As is the distance from the valve to the plenum?
Aslo the volume of the plenum plays are part. There are many variables and I'd thing that Nissan have done the developement work on this and by bolting in an 'uprated' parts and saying 'look, more power' does not actually tell the whole story.
A dyno gives very little indication of engine responce which is very important for getting the best from a race engine.
Maybe the willy waving is more important here, BTW I run 6 TBs now and I'm very happy with the performance and I see no performance gains with a single.
I have run a Q45 on my old RB30 but that was for simplicity reasons.
 

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Discussion Starter #56
I get that you're trying to compare JUST the ITB Vs STB without taking plenum into account but I really don't see how you can TBH....
As per the Hypertune Plenums, I understand what you mean TT but is should simply be a direct comparison if the plenum design is the same?





Maybe the willy waving is more important here, BTW I run 6 TBs now and I'm very happy with the performance and I see no performance gains with a single.
I have run a Q45 on my old RB30 but that was for simplicity reasons.
Summing up exactly my thoughts Andy.
 

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But your forgetting not every cylinder is taking 100% capacity of air at a time, your also not including what that spindle does air flow. Your also forgetting say you have a greddy plenum your still restricted by 4" inlet at best. So my air flow will just be slightly restricted by 1 spindle but of course it will have a lot less effect as its supplying 6x cylinders what are not all drawing air at the same time so can accomdate enough air to say every cylinder can have 100% air when the valve opens were as with the itb when the valve opens the air flow is drastically effected by a spindle in the way

Amt allways said on a diffrent port shape they would be brilliant but on the rb26 head there not
I'm not forgetting any of that, I'm just throwing some random numbers out to try and start discussion on the original question, are ITBs inherently better than singles. Every engine is a system and of course you could drone on for hours about inlets, reversion, valve open time, runner length, plenum volume, free velocity, etc etc, but that wasn't the question.

Most of these points are moot anyway because a well optimised and easy breathing engine will increase volumetric efficiency... very important on something like displacement and RPM limited NA race engines, not so important here, because you could just turn the boost up a bit and get the same result. You're chasing tiny numbers for a lot of work on a forced induction (engine in most cases).

There's definitely some axe-grinding at work here rather than what I'd hoped would be an interesting discussion!
 

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I would have to say the reason Hypertune say the 6 throttle is a restriction past 400hp is that they make an expensive single throttle body to go with their plenum.....but none for the 6 throttle version.....just marketing.

.....have they got flow bench charts between their two plenums showing this fact???
 

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I would have to say the reason Hypertune say the 6 throttle is a restriction past 400hp is that they make an expensive single throttle body to go with their plenum.....but none for the 6 throttle version.....just marketing.

.....have they got flow bench charts between their two plenums showing this fact???

I'm sure they have Chris il email them to see if they have, high octane built there r32 with a hypertune multi tb plenum then when they built there 34 they went with a 90mm single and stuck with it that must be for a reason otherwise they would go back to multi.

What the reason rips use singles on more less all there builds to Chris?
 
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