**CHALLENGE** - TURBO LAG TEST using a log

[coker6303]

How long does it take to go from 0psi to 20psi when flooring your truck from a standstill?

Don't go heat the turbo(s) up, keep it fair. I was sitting at 240deg EGT when I made my run.

3.57 sec to go from 12.2-32.8psi on the MAP sensor.

 

[matt78]

Be nice to your truck russ, its the holidays.

 

[coker6303]

I pumped diesel in her today, Merry Christmas! lol

I can't figure out how to attached the log file... retard moment I guess

 

[Harbin_22]

This is a decent idea but 20#'s from a stocker and 20#'s from say a single 475 are two totally different things. I will check it out on mine next time it comes out of the garage

 

[JoshH]

This is a decent idea but 20#'s from a stocker and 20#'s from say a single 475 are two totally different things. I will check it out on mine next time it comes out of the garage

How's that?

 

[jkholder09]

How's that?

If you watch the Maf the g/s on a 475 will be the same as a stock ihi at about 10 psi compared to the 20 the stocker is pushing for pressure ratio.
The 475 is moving way more air

But its all good Josh because we are going to have real live data here to test our assumption's :thumb

 

[Harbin_22]

Be like saying a stocker making 45#'s will make same power as a 475 making 45#'s. We all know the answer to that

 

[JoshH]

Be like saying a stocker making 45#'s will make same power as a 475 making 45#'s. We all know the answer to that

A stocker at 45 psi is way out of its map. At 20 psi, they are both in their map. With both on a motor with stock heads and cam, I can't see the amount of air flow being all that different if any.

 

[IOWA LLY]

Airflow, or exhaust flow rather will be much more on an S400 over a stocker. So 20 psi of boost could very possibly be much more airflow on the larger aftermarket charger.

Lots of variables. To many in my opinion to make this test amount to much.

A better test would be to pick an avg rpm for say 60mph, then do a log with converter locked and NO downshift and see how long each takes to light. Say 10-15 psi.

Sent from my SCH-I535 using Tapatalk 2

 

[plowboy_lbz]

Airflow, or exhaust flow rather will be much more on an S400 over a stocker. So 20 psi of boost could very possibly be much more airflow on the larger aftermarket charger.

Lots of variables. To many in my opinion to make this test amount to much.

A better test would be to pick an avg rpm for say 60mph, then do a log with converter locked and NO downshift and see how long each takes to light. Say 10-15 psi.

Sent from my SCH-I535 using Tapatalk 2

Now that sounds like an idea. Would really give some real world results as to how well a charger can be DD'd

 

[jkholder09]

Rescale the maps josh so the axis are identical then lay one over the other.
The 475 eill be much further to the right

from mobile

 

[coker6303]

The whole idea is just to have something to compare against for spool up speed. Is anyone else willing to give it a try? I understand there are variables, but ignore that and give it a whirl. Let's just see what happens. :thumb:

 

[Burn Down]

Gonna be spring for me... Just came back from Hawaii, over a foot of snow on the hood lol. Besides 20 psi on ice equals in the ditch on my head:thumb:. Carry on folks.

 

[coker6303]

Don't need you in the ditch! I'm glad it doesn't snow down here, I would be in trouble!

Is anyone else going to test? I would really like to see a comparison. Only takes a sec to go do a short log :thumb:

 

[NC-smokinlmm]

Airflow, or exhaust flow rather will be much more on an S400 over a stocker. So 20 psi of boost could very possibly be much more airflow on the larger aftermarket charger.

Lots of variables. To many in my opinion to make this test amount to much.

A better test would be to pick an avg rpm for say 60mph, then do a log with converter locked and NO downshift and see how long each takes to light. Say 10-15 psi.

Sent from my SCH-I535 using Tapatalk 2

With the converter locked and no downshift I will never hit 20 psi... Lol..

JK, but I sure won't get to anywhere near normal boost numbers and spoolup will be slowwwww...

I like the first idea better, I'm gonna give it a shot here shortly before it starts to rain...:woott:

 

[IOWA LLY]

With the converter locked and no downshift I will never hit 20 psi... Lol..

JK, but I sure won't get to anywhere near normal boost numbers and spoolup will be slowwwww...

I like the first idea better, I'm gonna give it a shot here shortly before it starts to rain...:woott:

That's why I said 10-15 psi.....

Testing turbo spool from a standstill proves or shows very little as converter selection will rule this test. That's why I suggested testing with a locked converter, everyone at the same start RPM, etc. If you don't take away as many variables as possible this test will with be worthless and a complete waste of everyone's time....


Don't believe me? My pulling truck will light the charger in less then 4 seconds (log proven) from an idle on the highway. Believe me, that charger is NOT streetable!

 

[coker6303]

Don't believe me? My pulling truck will light the charger in less then 4 seconds (log proven) from an idle on the highway. Believe me, that charger is NOT streetable!

I'm assuming your converter it so loose it would be miserable on the street too?? Or just talking about revving through the roof with a manual? This is geared towards the daily drivers, not purpose built race/pull trucks. I guess I should have stated that in the beginning

I don't mind doing a test from a roll either, simply write a trans tune that won't down shift and agree to a 5th gear, 1500rpm pull or whatever seems feasible. I just want to see spool up, and both scenarios are useful.

 

[DMAXchris]

I'll do a log as soon as my Airdog is working again. New motor should be here this week.

From a roll would be interesting too. I could do 5th with the TCC locked, just gotta make sure no one is behind me. The vvts will have the advantage.

 

[catman3126]

I'll do one the next time I drive mine. I have a dyno tune that holds 5th lockup in T/H

 

[Chevy1925]

I'm assuming your converter it so loose it would be miserable on the street too?? Or just talking about revving through the roof with a manual? This is geared towards the daily drivers, not purpose built race/pull trucks. I guess I should have stated that in the beginning

I don't mind doing a test from a roll either, simply write a trans tune that won't down shift and agree to a 5th gear, 1500rpm pull or whatever seems feasible. I just want to see spool up, and both scenarios are useful.

he has a good point Russ, i do like your test though! brian, sean and i were jsut talking about testing this with others yesterday.

Here is my feed back on my stock turbo over my s475 with batmowheel/Yellowchevy upgrade.

At 60mph, 5th gear TC locked, 1500rpm, no load and without letting it down shift, i can hit 20psi at just over a second but its also building 1-2psi of boost before rolling into the throttle. its hard to be "out of boost" so to speak on my setup.

ill see if i can get a log now but i just swapped to 4.56 gears so its REALLY hard to get it out of boost now. i was almost borderlined before due to the longer time between shifts



This whole test your doing is something i was trying to figure out a long while back before i did twins. i finally got Andrew on here to do a loaded test with his truck (bascially the same as mine but with 35s and triple turbos with a 366 as the high pressure). under the same circumstances as i said above but loaded, he could not get boost to build until 1800 rpm. that right there answered my question on whether or not id ever jump up in charger size (i wont).