MIKE10SECV6
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- Jan 24, 2003
Larger throttle body discussion...pros and cons
- Thread starter DonnieShort
- Start date
DonnieShort
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- May 27, 2001
Well, after the last several posts you helped me make my mind up and I'm going to keep it all and bolt it on. We've even made plans to go to BG on 7/5 for the test & tune night to get this thing dialed in so I should have some results pretty soon. Even if it doesn't help, it damn sure does look good. Needless to say, I have the best wife anyone could ask for. 
DonnieShort
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- May 27, 2001
Boy did I have to dig for this thread
I got to go to the track (BG ), on 7/5 but didn't get to run with the new upper, power plate and tb because the upper was on back order at the time ( getting polished ). And eventhough I didn't run it, I still ran a new best of 11.542 @ 116.28mph, previous was 11.79 @ 113mph.
But the upper came in on 7/21 and installed it yesterday, and I have to say that I can tell a pretty good difference in off idle zip. Now I don't know what part's responsible, the power plate, tb or upper. And it may be a combination of all three working together. But spool up is faster and I picked up 3 psi boost with the same wastegate setting and the car feels livelier top to bottom including a bit more top end grunt.
Even if it doesn't help, it sure does look good
I got to go to the track (BG ), on 7/5 but didn't get to run with the new upper, power plate and tb because the upper was on back order at the time ( getting polished ). And eventhough I didn't run it, I still ran a new best of 11.542 @ 116.28mph, previous was 11.79 @ 113mph.
But the upper came in on 7/21 and installed it yesterday, and I have to say that I can tell a pretty good difference in off idle zip. Now I don't know what part's responsible, the power plate, tb or upper. And it may be a combination of all three working together. But spool up is faster and I picked up 3 psi boost with the same wastegate setting and the car feels livelier top to bottom including a bit more top end grunt.
Even if it doesn't help, it sure does look good
GNVYUS 1
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- Dec 15, 2002
I noticed the same 3 psi increase in spool after installing my 70mm accufab TB and I had the stock mount IC with the dutt neck at the time. The V2 gained 2.5 over that mark and the car roasts them now at 40 mph on a hammer down and only 17 psi.
I have a mbc on the car so I know exactly how much psi is gained on every mod. The 70mm TB was the best gain in psi I have done on this car.
I have a mbc on the car so I know exactly how much psi is gained on every mod. The 70mm TB was the best gain in psi I have done on this car.
KillerV6- you should be watching this thread like the rest of us considering the mods you have done should have your car in the low 12's if not high 11's already. 97mph with all those mods even on pump gas!?!?
The point being made is why spend $250.... when you can spend $80 and get 95% of the results if not more. Ryan Guy's 9.99@135mph+ in a 3500lb+ GN running a stock 62mm TB is hauling *ss so they must work fine. And knowing those guys from OR if a 70mm TB would make it run faster.... they would have one on there.
Stock block past 9.90's in a full weight Regal is just asking for trouble in the long run.
-GNX7
The point being made is why spend $250.... when you can spend $80 and get 95% of the results if not more. Ryan Guy's 9.99@135mph+ in a 3500lb+ GN running a stock 62mm TB is hauling *ss so they must work fine. And knowing those guys from OR if a 70mm TB would make it run faster.... they would have one on there.
Stock block past 9.90's in a full weight Regal is just asking for trouble in the long run.
-GNX7
DonnieShort
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- May 27, 2001
Actually, the point of this thread was to find out if a larger tb and plenum would help or hurton a mid 11 sec car. In my case, as posted earlier, the money had already been spent ( a gift from my wife ) and I was going to send the stuff back if it was going to be a hinderence. And alot of people who's opinion I respect said to go ahead and strap it on and that convinced me to keep and install it. And after the installation, the car has alot more zip and zing by way of 3 psi boost ( more closer to 4 psi ) at the same wastegate setting. Now, the upgrade may not help any at all as far as et's and mph, but it might and I will post those results as soon as I can get back to the track. Plus it looks great!! Besides, once you hit mid 11's, the tenths and mph don't come as cheap as they did in the 13's and 12's.
heh im watching this thread very closely actually.
my 13.7 was before any mods. i ran my 13.7 at 97 w/ a FWD MAF sensor, cracked manafold, and ed valvo chip w/ 15 psi on street tires.
i didnt meen "why not throw it on any wayz", i ment why not see if it can make a diffrence and look into it before just saying "there are cars runing 9's with stock TB end of story".
this is intresting stuff!
my 13.7 was before any mods. i ran my 13.7 at 97 w/ a FWD MAF sensor, cracked manafold, and ed valvo chip w/ 15 psi on street tires.
i didnt meen "why not throw it on any wayz", i ment why not see if it can make a diffrence and look into it before just saying "there are cars runing 9's with stock TB end of story".
this is intresting stuff!
GNVYUS 1
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- Dec 15, 2002
Here is something from rjc's site
"Here are some solid flow percentages.
The stock plenum and t.b without a power plate as a baseline.
Stock tb. 100%
Stock tb. with ADPPs plate 100-102%
Precision plenum with 70mm t.b. 123%
Precision plenum with 70mm + ADPPp plate 120%
Kenny Bell plenum with 70mm t.b. 125%
Kenny Bell plenum with 70mm + ADPPk plate 111%
Hemco Plenum with 70mm tb 113% "
It pretty clear that the bigger plenums outflow the stocker by 20-25% without the plate on. If you have an 11 second car pushing larger amounts of cfm over the stock turbo, than this mod has to be worth doing just from the data above. Of course, the next bottle neck is the intake, than the heads. But you have to start with the "Cheap and Easy" first.
Now comparing it dollar per dollar to a ported Jay Jackson is another issue all together. Jays the man and should get into doing Eclipse and Talon tb's as those those guys are getting hammered for a 4mm port job Jay.
The con to the 70mm is that the larger plenums and tb are supposed to lose some low end. I actually noticed an increase in spool up!!! The only con I have personally seen is in the pricing.
"Here are some solid flow percentages.
The stock plenum and t.b without a power plate as a baseline.
Stock tb. 100%
Stock tb. with ADPPs plate 100-102%
Precision plenum with 70mm t.b. 123%
Precision plenum with 70mm + ADPPp plate 120%
Kenny Bell plenum with 70mm t.b. 125%
Kenny Bell plenum with 70mm + ADPPk plate 111%
Hemco Plenum with 70mm tb 113% "
It pretty clear that the bigger plenums outflow the stocker by 20-25% without the plate on. If you have an 11 second car pushing larger amounts of cfm over the stock turbo, than this mod has to be worth doing just from the data above. Of course, the next bottle neck is the intake, than the heads. But you have to start with the "Cheap and Easy" first.
Now comparing it dollar per dollar to a ported Jay Jackson is another issue all together. Jays the man and should get into doing Eclipse and Talon tb's as those those guys are getting hammered for a 4mm port job Jay.
The con to the 70mm is that the larger plenums and tb are supposed to lose some low end. I actually noticed an increase in spool up!!! The only con I have personally seen is in the pricing.
GNSCOTT, he's really right tho. As I understand it, boost is a product of restriction, not so much the turbo. IOW, the boost in your intake is the EXCESS air the turbo is flowing before the engine can injest it.
Now, lets sy your engine is heavily modded. Your motor can flow 700fm. For say a stock turbo to generate 700cfm, it needs to spin at 100,000 rpm. I believe the heat comes more mechanically then due to compression, whereas say a larger turbo will only need to spin 60,000 rpm to generate that same 700cfm. It will generate less mechanical heat.
As usual, maybe my terminology is wrong, but I know what I am trying to say. This is the REASON to go with a larger turbocharger after all.
As for a car with a larger tb giving the seat of the pants increase, its most likely due to this....
a stock TB can flow say 500cfm (or whatever..just a number) at WOT. A 65 TB can flow that same 500 cfm at say 1/2 throttle. SO it gives the illusion it made more power, when it simply moved the power to a lower throttle opening. This feels like you gained part throttle power, when in reality you are flowing previously WOT air, at less than WOT.
I am very interested in this thread, because I have a 70mm TB for my new mill, and wanna see what the deal is. I'm gonna tune for and use it, just cuz chicks dig it. I'm not expecting it to make me much more power. I have a TE63-1 which has a 3" outlet, 3" IC pipes, and wanted a 3" TB to remove the limiting link in my intake track. (My MAF pipe is 4" so I removed some of the pre-turbo restriction John mentioned as well) I just wanted to get the whole combo as optimized as possible. I thought I was doing the right thing.
http://www.turbojim.com:231/jim/rightside.jpg
http://www.turbojim.com:231/jim/leftside.jpg
Is what I got going together so far.
Now to read the rest of this thread....
Re: $$$???
http://www.gnttype.org/techarea/turbo/nointercooler.html
FWIW, note the uppipe. I've tried, 2.25, 2.5 and 3" piping there.
At the lower throttle openings the smaller pipes were noticebly crisper is response. At the expense of the engine not making as much HP at the upper end. And this is just a foot or so of open pipe.
The name of the game as I see it, is boost.
You want to build as much as possible with the least backpressure.
As far as air distribution goes, the lower the velocity of the air in the plenum, the easier it will be able to turn and respond to valve openings, and closings.
So far big pipes, and increasing the plenum volume have worked for me. I've added about 50% more plenum volume, to the stock one, and it made a signifigant difference.
In the end the only way to really tell, if it's going to work for your combination, is to actually try it. There seems to be no small demand for used parts, so at worst you'll be able to recover 80% of any investment, and that ain't bad.
BTW, I have a 65mm coming, and a M+A sitting in the living room waiting to go on.......
http://www.gnttype.org/techarea/turbo/nointercooler.html
FWIW, note the uppipe. I've tried, 2.25, 2.5 and 3" piping there.
At the lower throttle openings the smaller pipes were noticebly crisper is response. At the expense of the engine not making as much HP at the upper end. And this is just a foot or so of open pipe.
The name of the game as I see it, is boost.
You want to build as much as possible with the least backpressure.
As far as air distribution goes, the lower the velocity of the air in the plenum, the easier it will be able to turn and respond to valve openings, and closings.
So far big pipes, and increasing the plenum volume have worked for me. I've added about 50% more plenum volume, to the stock one, and it made a signifigant difference.
In the end the only way to really tell, if it's going to work for your combination, is to actually try it. There seems to be no small demand for used parts, so at worst you'll be able to recover 80% of any investment, and that ain't bad.
BTW, I have a 65mm coming, and a M+A sitting in the living room waiting to go on.......
Jim...that was a damn good explanation . The reason I thought it worked differently was I thought that when the air was cooled and became dense, that more cool dense air came in to take that space up and that is why you run more boost just by installing an intercooler, ie. because now you can fit more air into the cylinders because now the air is denser.
I have to keep the 90mm tb anyways, unless I wanna do fab work to the intake, and I know with the 88 it won't hurt me. Maybe i'll make an adaptor plate and dyno it with a 70 and 90 and get some #'s.
. The reason I thought it worked differently was I thought that when the air was cooled and became dense, that more cool dense air came in to take that space up and that is why you run more boost just by installing an intercooler, ie. because now you can fit more air into the cylinders because now the air is denser.I have to keep the 90mm tb anyways, unless I wanna do fab work to the intake, and I know with the 88 it won't hurt me. Maybe i'll make an adaptor plate and dyno it with a 70 and 90 and get some #'s.
Heat of Compression..
Mmm, boost is not really a product of restriction. "Boost" is obtained by compressing the air so that the engine intake manifold is getting air at a higher DENSITY than the atmosphere. The compressor had to be big enough to supply all the air that the engine can use, which depends on cubic inches and rpm. The Buick engine, for example, can only use about 350 cfm, with no boost. That's 350 cfm at 14.7 psia. If you want to double the pressure, by going with 14.7 psia boost, then the turbo will intake 700 cfm at 14.7 psi, but will only discharge 350 cfm, at 29.4 psi. Even then, you won't get twice the amount of air, because the compression heats the air, and the density won't double, even though the pressure will. Most of the heating IS due to compression, not from friction. An intercooler will help recover some of the density, but no all, unless you use a refrigerated intercooler. The 231 cubic inch engine will only swallow 115.5 cubic inches of air on one revolution, so to get to 700 cfm at the engine, you would have to go to about 10,000 rpm. Too much for the stock block, I think. Much cheaper, and easier, to get the engine to swallow air which is more dense. As Scott said, you can get more air (in pounds) into the engine when it is denser. Note that Bruce's non-intercooled engine will require 30 psi boost to get the same airflow an intercooled engine will get with 18 psi boost. And because the hot air is less dense, it takes bigger pipes to flow the same amount.
Mmm, boost is not really a product of restriction. "Boost" is obtained by compressing the air so that the engine intake manifold is getting air at a higher DENSITY than the atmosphere. The compressor had to be big enough to supply all the air that the engine can use, which depends on cubic inches and rpm. The Buick engine, for example, can only use about 350 cfm, with no boost. That's 350 cfm at 14.7 psia. If you want to double the pressure, by going with 14.7 psia boost, then the turbo will intake 700 cfm at 14.7 psi, but will only discharge 350 cfm, at 29.4 psi. Even then, you won't get twice the amount of air, because the compression heats the air, and the density won't double, even though the pressure will. Most of the heating IS due to compression, not from friction. An intercooler will help recover some of the density, but no all, unless you use a refrigerated intercooler. The 231 cubic inch engine will only swallow 115.5 cubic inches of air on one revolution, so to get to 700 cfm at the engine, you would have to go to about 10,000 rpm. Too much for the stock block, I think. Much cheaper, and easier, to get the engine to swallow air which is more dense. As Scott said, you can get more air (in pounds) into the engine when it is denser. Note that Bruce's non-intercooled engine will require 30 psi boost to get the same airflow an intercooled engine will get with 18 psi boost. And because the hot air is less dense, it takes bigger pipes to flow the same amount.
The Radius Kid
Active Member
- Joined
- Jan 26, 2002
Re: Heat of Compression..
Jimmy's right.
*Pressure or "boost" is a function of flow VS. resistance to flow*.
PV/T's may change with frictional losses,but ultimately[as you stated Ormand],the compressor you're using and the engine being fed will determine the boost characteristics of your combo[among other things].
Jimmy's right.
*Pressure or "boost" is a function of flow VS. resistance to flow*.
PV/T's may change with frictional losses,but ultimately[as you stated Ormand],the compressor you're using and the engine being fed will determine the boost characteristics of your combo[among other things].
I guess I just don't like to use the word "restriction". If "boost" is caused by restriction, then all I have to do to increase boost is to use a restrictor plate in front of my throttle body, right? But in that case the engine would "see" even less flow. The engine is not really a restriction, in the sense that a too-small intercooler is a restriction, or clogged up cat is a restriction. You choose to run a turbo of a certain size, and an engine of a certain size, at a certain rpm. The balance of flow rates will govern the outlet pressure of the turbo. If you put a larger turbo on the engine, without increasing the engine size, or the rpm of the engine, you can get more boost. But you didn't change the "restriction" at all, did you? By the way, the Mitsu guys have got a neat little on-line calculator that will let you calculate turbo outlet temp, and intercooler outlet temp, and most important, the DENSITY ratio. It is, after all, the factor which most affects power. It is here:
http://www.stealth316.com/2-turbotemp.htm
The calculator will let you pick the compressor efficiency, so you can see what the temp would be with NO friction. It will also let you pick the intercooler efficiency. Pretty cool, I think.
http://www.stealth316.com/2-turbotemp.htm
The calculator will let you pick the compressor efficiency, so you can see what the temp would be with NO friction. It will also let you pick the intercooler efficiency. Pretty cool, I think.
No because boost is intake manifold pressure, you would have to restrict the boost after the point in which it is measured. If you closed up the ports in the intake or heads you will run higher boost because more will back up into the intake manifold. That is why with ported heads, you will make more HP with the same amount of boost because the heads are a major blockage in our motors, the same reason why if you run a bigger AR you will pick up HP, but at the sacrifice of spoolup.
Its all about air flow through the enire system, from intake to exhaust tip, the less restriction, the more HP. You can either make stuff bigger (porting, bigger parts) or you can make the air more dense so you can flow more air through ie. an intercooler or NO2.
Its all about air flow through the enire system, from intake to exhaust tip, the less restriction, the more HP. You can either make stuff bigger (porting, bigger parts) or you can make the air more dense so you can flow more air through ie. an intercooler or NO2.
If you were measuring boost in the uppipe, yes. But since power is made after the TB, the "restiction" in our cases is the fact the turbo may be pushing 1000cfm, but the engine is only injesting 750. That "extra" shows up as manifold "pressure" or boost.
Dont forget, lets say at atmosperic pressure, our engines can ingest 380cfm did you say? Ok, we use boost to make power because it may take 15psi or 20psi or 30psi or pressure to force 500, 700, 900 cfm thru the little openings that were designed to flow 380fm.
Matter of fact, how does a bleed or sneeze valve work? By sensing excess pressure or boost] at throttle closing (big restriction there huh?) Boost ahead of the TB actually spikes due to the fact the compressor is still spinning at a high rate, causing the valve to unseat and vent this extra pressure to atmosphere instead of letting it bounce off the throttle blade and back into the compressor outlet (compressor slam)
No, you didnt change the restriction, but you added the ability of excess supply. Think of it this way. You buy a craftsman 1hp air compressor (turbocharger) to run your air ratchet wrench (the engine). Its rated at say 4cfm @ 90psi (size of the turbo). The ratchet uses 4 cfm @ 90psi (amount of air the engine can use). You hate the fact that you haveta wait 5 mins between bolts (turbo is out of efficiency range and cant keep up, so you have surging, or superheated air), so you buy a 5hp compressor (bigger turbo) rated at 10cfm @ 90psi and now your air ratchet is happy as long as you need it. You didnt change the restriction (the ratchet) you upped supply so now you have excess air pressure, which this "boost" is now stored in the compressor tank.
Is this a tomato vs tomatoe thing? Maybe, its just the way I see it.
