2.5" Inlet and 3" outlet for Intercooler?

[Z2TT]

Some good points.

So what I get it at so far is it's a good idea to go a larger pipe after the inter cooler because you lose pressure from the inter cooler and want to keep the air cool by using a larger pipe.

If We had a compressor with a 2" Outlet, and an Intercoooler with 2.5" inlet/outlet, Then would a reccomended setup be to run 2" pipe to the intercooler? Then from the 2.5" outlet use an expander to use whatever pipe diameter is closest to the diameter of the throttle body?

Question I got, couldn't you just run 2" Piping to the cooler and out of the cooler anyway, and if you have a larger throttle body, wouldn't the air just expand at the throttle body and get cooler, so does that mean there is no need to run a larger outlet intercooler pipe for expansion, since the air will expand at the throttle body anyway if its larger?

Almost every kit for everycar seems to have same diameter pipes all round, like 3" in, and 3" out. I'm wondering why more manufacturers don't experiment with different diameter pipes.

[auto351]

I'd suggest that using these three relationships, having the smaller piping between turbo and cooler means less backpressure on the turbine and higher air speed.

I would have to disagree with the smaller piping resulting in less backpressure on the turbine.

but looks like we are all thinking along the same path (more or less)

In the old days of CD players (yes correct compact discs) the makers would oversample the data; the only benefit of this was to install a cheaper filter.

The same looks to apply here by over compressing the air the intercooler leaving temp will be lower than if the turbo leaving pressure was lower
From what I remember at tech the higher the temp difference the more heat energy will be transferred, if the temp was twice as hot into the intercooler (due to over compressing) the intercooler would loose twice the heat energy while it will be hotter at this point (than running normal boast) when you drop the pressure (due to pipe work sizing) to normal operating pressure this cooling could result in cooler air”
I will research this a bit more.



The key here is the over compressing this is assuming the turbo can handle the extra pressure?
One way you could simulate this would be to run a restrictor on the outlet of the intercooler?

http://www.stealth316.com/2-adiabat1.htm
http://www.stealth316.com/2-turbotemp.htm
http://bowvalleycollege.ca/library/q...20/gaslaws.pdf

[forey]

as far as i know rule of thumb.. compressor outlet size to intercooler then whatever TB size is from IC to TB...

if your IC has 3" inlet and outlets just get silicon reducers

[auto351]

Just following up from my last post with some links & numbers on over compression


Example 1:
If we run the turbo at normal pressure 12PSI (wanted) assume a 2 PSI loss in the system then total turbo pressure is14PSI and the temps are entering temp 25.5c
Leaving turbo 109c leaving intercooler 41.7c


Example 2:
Running the turbo at +14PSI above the wanted pressure total pressure is now 28PSI
Leaving turbo 167c leaving intercooler 53.3c

While the intercooler temp is higher there is free cooling to come
In this case there is another temp loss by dropping the remaining 28PSI to 14PSI which I have calculated at -108c leaving temp after the point of decompression, sounds to cold, but if we look at the turbo temp difference between the two examples(167 - 109) 58c this is more likely the drop in temp which would give a leaving temp of -4.7c.

so this is indicating that over compressing results in lower air temp?

Question I got, couldn't you just run 2" Piping to the cooler and out of the cooler anyway, and if you have a larger throttle body, wouldn't the air just expand at the throttle body and get cooler, so does that mean there is no need to run a larger outlet intercooler pipe for expansion, since the air will expand at the throttle body anyway if its larger?

Yes, you can use the throttle body as the exansion point and that would be the best location,
The size of the pipe work up till that point make little difference as long as its larger.
you will need to work out flow verse area by PSI you may find you need to fit a 1" reducer just before the throttle body to get results.


Also while find these formulas, one site was indicating that a temp drop of 10c = 1% performance increase???


The sites below have explanations.

http://www.stealth316.com/2-adiabat1.htm
http://www.stealth316.com/2-turbotemp.htm
http://bowvalleycollege.ca/library/q...20/gaslaws.pdf

[big_zop]

What exactly are you trying to prove by the last statement of 'free cooling'?

Are you actually suggesting that if you overboost the turbine to 28psi and then somehow manage to drop the boost pressure back to 14psi that this drop in pressure will also cool the intake charge? If so, how exacly do you propose to do this - by the differing pipe diameters?

[ReQuieM]

Ok I think people are going way to indepth here on tangents that have no real discernible effect, Here is a simple way of looking at it;

Hot air is expanded, but moves at a higher velocity.
Cool air is contacted, but moves slowed.

SIMPLE logic, when the larger faster flowing air gets cooled it slows down and contracts. There for keep the piping the same size, because you will need lots of expanded air to create slow contacted air that will take longer to get to the TB. If the piping on the intake side is too small the slow moving air will create a bottleneck for the faster moving air entering the IC and also mean there is less CFM of air (power maker) available for the engine to run.

Stop thinking of the IC piping as primeries, secondarys plenums. Start thinking off it as an exhaust system. Harmonic pulses WILL NOT directely effect the air speed in the IC piping. They only effect the runners and will reflect off the end of the runner or plenum wall opposite the runner. All of which is after the TB, all harmonic pulses are reflexed or dispersed at large volume changes.

For me, I keep the the same because what you lose in air volume your also loose in speed so you need the pipe volume.

[Z2TT]

So is what your saying is by using a smaller diameter pipe on the turbo-intercooler side, you cant supply enough air to fill the larger pipe on the intercooler-throttle side a decent amount?

[ReQuieM]

simplistically yeah. Not enough oxygen rich power making yeah.

Really, as stupid as it seams, you would be better off with the smaller pipe on the cold side in an attempt to keep up the cooled airs velocity. But as has already been mentioned by a few others, that velocity would all so hamper the cooling. Basically either way you go, small-big big-small, there is a draw back. Unless your prepared to do back to back testing, the safest bet is to run the same on each side.

Also what has been said about over sizing is true too, just like an exhaust, you go to big and you loose too much velocity all round. Keep in mind that a turbo creates pressure, PSI, by super speeding up the incoming air. Too big and you make the turbo work over time. Too small and you can't flow the CFM that the engine needs to create power.

HTH

[datsik]

Looking at this question, I agree with some of the guys (celicapain),, but the larger the pipe work diameter the better and this is because of the pressure drop thought the system will be less, the formula pressure = Air flow * Pipe resistance,
If your running 12PSI at the engine and you have a 10PSI loss across the system them your total turbo pressure will be 22PSI, I’ve hear numbers like 100degress Celsius temp increases for every 10PSI boast (not sure if that’s exact but we can use this for our example)
If our pressure losses are only 5 PSI (due to large pipe work) then this would reduce the air temp by 50degress to start, so large piping would give lower running temp

.

the pressure drop will be less........however, larger pipes have larger surface areas which means that they can ABSORB heat from their surroundings...so going too big probably aint great...another thing not talked about is lag...the larger the pipe, the large the volume that needs to be filled.......the larger the lag experienced.

[JZA70R_92]

reason is 1J has 2.5 inch turbo outlet and throttle body is 3inch

[Z2TT]

Yeah i've noticed 1j seems to have a 3" Intercooker-tb pipe and smaller turbo to cooler pipe.

[ReQuieM]

Simple solution, modify the turbo outlet Y pipe to suit 3". I'm selling one atm as part of my performance stock turbo sell off. You can see it in classified section

[Z2TT]

Simple solution, modify the turbo outlet Y pipe to suit 3"

Does that give better performance?

[Casey-G]

Just following up from my last post with some links & numbers on over compression


Example 1:
If we run the turbo at normal pressure 12PSI (wanted) assume a 2 PSI loss in the system then total turbo pressure is14PSI and the temps are entering temp 25.5c
Leaving turbo 109c leaving intercooler 41.7c


Example 2:
Running the turbo at +14PSI above the wanted pressure total pressure is now 28PSI
Leaving turbo 167c leaving intercooler 53.3c

While the intercooler temp is higher there is free cooling to come
In this case there is another temp loss by dropping the remaining 28PSI to 14PSI which I have calculated at -108c leaving temp after the point of decompression, sounds to cold, but if we look at the turbo temp difference between the two examples(167 - 109) 58c this is more likely the drop in temp which would give a leaving temp of -4.7c.

so this is indicating that over compressing results in lower air temp?



Yes, you can use the throttle body as the exansion point and that would be the best location,
The size of the pipe work up till that point make little difference as long as its larger.
you will need to work out flow verse area by PSI you may find you need to fit a 1" reducer just before the throttle body to get results.


Also while find these formulas, one site was indicating that a temp drop of 10c = 1% performance increase???


The sites below have explanations.

http://www.stealth316.com/2-adiabat1.htm
http://www.stealth316.com/2-turbotemp.htm
http://bowvalleycollege.ca/library/q...20/gaslaws.pdf

On the money there,

i figure the free cooling is linked somwhere in the pV=nRT equation.

the expansion of the air into the 3" (I/C outlet side) will be at a lower pressure to the inlet side but also at a lower temp.

And i reckon i'd take cooler air over higher boost any day.

[Z2TT]

Sounds Interesting, I guess then larger pipe on the outlet side is better since it provides an expansion point and also matches size of TB, and smaller pipe from Turbo to Intercooler for better airspeed and less lag?

Guess if 1jz's had a similar setup from the factory then it must be the proper way to do it?