Advantages Of 100mm And 70mm Intercooler?

[R34NRG]

I can't see how a bigger I/C can introduce noticable lag.

exactly......

i think 100mm compared to 60mm will introduce lag, but the big question is it enough lag to worry about when you have 10x more air flowing in making more power.

honestly i dont even think u can put a number on how much lag it will be.....maybe .5 of a second? not even?

wont even notice

Edited April 14, 2008 by R34NRG

[GeeTR]

If you reckon you wouldn't notice an extra .5s (i doubt very muchly that going to 3.5" IC piping and a 100mm would give that) from WOT to power delivery... you don't drive close enough the the edge ""Loose" is fast, and "on the edge" is out of control" lol.

Got 3 hours left tech head

Edited April 14, 2008 by GeeTR

[R31Nismoid]

You'll notice transient response onto boost, inbetween gear changes etc. Nothing that you'll ever really see on a dyno.

And as for making the cooler piping bigger, thats just silly for even a moderate setup on a GTR. Factory is perfect!

GTR gear (factory) is tried and proven by many cars that get tracked here without issue and using the factory item.

[700HP-GTR33]

well for starters the stock GTR core is only 60mm. so replacing it with a good quality 70mm core will be of some benefit. going to a 100mm core is a big jump up in size so unless you are making the sme kind of jump with turbo size etc I would not bother. plus it's a lot of extra weight hanging over the nose of your GTR that you just don't need.

+1

If you plan a Turbo upgrade latter....and have to change the IC.....go larger.

This is what I have

http://www.nengun.com/arc/intercooler-standard-position

[GeeTR]

This thread has become so off topic and random, I LoL'd

[**RB2530**]

Now I have done some calcs...Yes I am bored at work...I have resigned and starting a new job in 2 weeks...

I have done some numbers on the time difference between filling two intercoolers... I have compared a 600x300x76 with a 600x300x120...I have also taken some rough numbers from a GT35 corrected airflow chart and made a couple of other assumtions that I will explain....

Volume of I/C number 1 = 0.01368 cu m which = 0.4831 cu feet

Volume of I/C number 2 = 0.0216 cu m which = 0.7627 cu feet

Now this is the total envelope of the I/C...I made the assumption that the internal volume of the I/C was about 50% of this including the tanks...

So the difference internal volume between the two is = 0.1398 cu feet

Corrected airflow for a GT35 gets up to about 40 lbs / minute

Assuming an air density of 0.076lbs / cu feet this equates to 526cfm or 8.77 cfs...

So time taken to fill the extra 0.1398 cu feet at 8.77 cfs is equal to 0.016 seconds...

Now this is only a ball park calc but hopefully it makes sense and puts some scope around the lag issue with bigger I/Cs. I dont think lag becomes an issue.

[**RB2530**]

PS

If you also run large intake pipework the effect of a larger I/C would be less noticable (lag wise) because the overall change in intake volume would be smaller...

[djr81]

That is fine but you don't worry about turbo lag at the maximum airflow of the turbo.

Pick a point with a much lower PR and a smaller airflow.

You should find that it easilly gets to add tenths of a second to the time.

40lbs a minute is approx 400hp at the engine. But if you are off throttle & at lower rpm your airflow can be much, much lower than this. Which inturn means your lag is much more.

Remember there is throttle lag plus turbo lag to think about.

[**RB2530**]

That is fine but you don't worry about turbo lag at the maximum airflow of the turbo.

Pick a point with a much lower PR and a smaller airflow.

You should find that it easilly gets to add tenths of a second to the time.

40lbs a minute is approx 400hp at the engine. But if you are off throttle & at lower rpm your airflow can be much, much lower than this. Which inturn means your lag is much more.

Remember there is throttle lag plus turbo lag to think about.

True...but even of airflow is 1/10th the extra time taken then becomes 0.16s....

Something I didn't mention earlier was pressure drop...For the same airflow, the bigger I/C would in theory have smaller pressure drop from inlet to outlet. So that would in turn reduce lag...It may be that the lower pressure drop counteracts the extra time fill the I/C

As far as throttle lag is concerned, wouldn't it be the same irespective of the I/C...The same as lag from the rest of the intake pipework...

[djr81]

Actually the lower pressure drop is beneficial in a somewhat unexpected way. If you look at the efficiency of the compressor map you notice the higher the P/R the more heat the turbo will put into the air. So you don't just get a decrease in lag you also get a decrease in the amount of cooling the intercooler needs to do.

[**RB2530**]

Actually the lower pressure drop is beneficial in a somewhat unexpected way. If you look at the efficiency of the compressor map you notice the higher the P/R the more heat the turbo will put into the air. So you don't just get a decrease in lag you also get a decrease in the amount of cooling the intercooler needs to do.

Yep I agree...Thats true for any type of pump, transferring any type of fluid...It just so happens that with air it is very easy to heat...thank god for modern turbine design...more energy into moving air, less energy into heating it...