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

[jkholder09]

Hey guys we need to see maf data and Iat as well in these logs. Yes lighting the turbo and getting on top of it is the goal......but I think these larger singles are actually moving sone decent air 0-20 psi after that we start to max out the maf sensor

from mobile

 

[Chevy1925]

idle to WOT



close to 1500 rpm roll in 5th gear TC locked. Cant go WOT without down shifting, that as much throttle as i can give it before down shift occurs and im not making a TCM file for something that my truck would never see to use lol



info wise

ported/polished stock turbo with batmowheel with a s475 in front of that

70* outside temp

37s and 4.56 gears

 

[JoshH]

Hey guys we need to see maf data as well in these logs. Yes lighting the turbo and getting on top of it is the goal......but I think these larger singles are actually moving sone decent air 0-20 psi after that we start to max out the maf sensor

from mobile

Without being in a stock intake tube, the likelihood of the MAF sensor being accurate is pretty slim. Besides that, I still don't see how 20 psi at X RPM with the exact same cam, heads, intake manifolds, etc is going to be that much different regardless of what turbo is being used.

 

[jkholder09]

Without being in a stock intake tube, the likelihood of the MAF sensor being accurate is pretty slim. Besides that, I still don't see how 20 psi at X RPM with the exact same cam, heads, intake manifolds, etc is going to be that much different regardless of what turbo is being used.

If the maf is scaled corrrectly It will be accurate.

I need to get some data for you josh you will be intriqued I believe

from mobile

 

[JoshH]

If the maf is scaled corrrectly It will be accurate.

I need to get some data for you josh you will be intriqued I believe

from mobile

The only data I'm interested in is if someone can explain how one turbo can flow more air through the same restriction at the same pressure than another turbo.

 

[S Phinney]

The only data I'm interested in is if someone can explain how one turbo can flow more air through the same restriction at the same pressure than another turbo.

By speed if air flow is how he can. A scaled MAF will be accurate. Problem us I don't believe very many worry about that part of the tuning enough.

Sent from my XT1080 using Tapatalk

 

[Muff]

The only data I'm interested in is if someone can explain how one turbo can flow more air through the same restriction at the same pressure than another turbo.

The way i see it your correct. The engine is the restriction point. A bigger turbo has more potential to flow more air, but 20 psi measured at the y bridge is 20 psi. A bigger turbo isnt pushing any more air at 20psi, it has potential to make more air faster and farther into the rpm range more efficiently yada yada yada.

If you have a gauge in the y bridge, when you build 20psi with a stock charger its the same flow of air as 20 psi with a bigger charger. The volume of air in the pipe is still the same.

Thats just the way i see it though i could be completely off base.

 

[Harbin_22]

I guess it could be in the exhaust side of things too but Funk made 650hp only making 30#'s of boost with a single 483. A stock turbo is still in its map at 30#'s and ain't going to make 650 HP. I could be wrong but I think it is volume deal. Surely not trying to argue with anyone over it but 30#'s of boost isn't the same between all turbos wether it be from exhaust housing differences or whatever, it isn't the same.

 

[Chevy1925]

I can tell you my maf is not accurate. I have it scaled to only do a little bit of work on purpose.

 

[jkholder09]

By speed if air flow is how he can. A scaled MAF will be accurate. Problem us I don't believe very many worry about that part of the tuning enough.

Sent from my XT1080 using Tapatalk

Pie r squared of both intakes then divide them. That is the ratio multiply by that percentage you will be close except under 100 g/s.
The wire is using less current to maintain temp so you can reduce that area by about 25%

from mobile

 

[jkholder09]

The only data I'm interested in is if someone can explain how one turbo can flow more air through the same restriction at the same pressure than another turbo.

The way i see it your correct. The engine is the restriction point. A bigger turbo has more potential to flow more air, but 20 psi measured at the y bridge is 20 psi. A bigger turbo isnt pushing any more air at 20psi, it has potential to make more air faster and farther into the rpm range more efficiently yada yada yada.

If you have a gauge in the y bridge, when you build 20psi with a stock charger its the same flow of air as 20 psi with a bigger charger. The volume of air in the pipe is still the same.

Thats just the way i see it though i could be completely off base.

Èxactly. You will build less boost with a powermax than stock. Given you run the same tune.
Pfm josh .........that's the best I can do for now.

But I am sort of thinkibg it has to do with gas law and iat.
If the air charge is cooler due to compressor efficiency than it Is much denser.
Dense air at 20 psi does have more mass.

Josh take some hot air from your lungs and blow up a balloon. Now put the balloon in the freezer. Post resulting pressure difference.

Did the mass of the balloon and air change?


Sorry had to go there bud.


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[jkholder09]

http://en.m.wikipedia.org/wiki/Density_of_air


Pv=nrt
Pressure and volumn are the same.
R is the gas constant so we solve that to
N/t I think where n is maf and t is iat.

So basically the difference between 300 degree air and 150 degree air is 50% of the mass.

I hope this makes sense to you guys and I did the math correctly.

Why would gm add a maf if boost measured total airflow.


from mobile

 

[coker6303]

Guys, let's stay focused and keep this simple....

For what we are testing, I really don't care if one flows more at 20psi or not. let's just collect data that reflects the driveability of a given setup.

I really want to get a broad range of logs to throw together a list. Help me out here! :thumb:

 

[jkholder09]

Can we discuss what needs logged?

I vote
Iat
Maf
Baro
Boost
Rpm
Ambient temp
Gear range
Tc lock
Main inj timing
Fuel pressure


from mobile

 

[S Phinney]

Pie r squared of both intakes then divide them. That is the ratio multiply by that percentage you will be close except under 100 g/s.
The wire is using less current to maintain temp so you can reduce that area by about 25%

from mobile

I can make it spot on though. I don't do close on it. I use before and after MAF readings and adjust by percentage from readings. Pipe sizes will not be accurate. Especially in compound setups.

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[coker6303]

Anyone else going to log?

 

[CaptPhil]

i will, but it will be next weekend at the earliest when i get back home.

 

[DMAXchris]

I still haven't had time to change Airdog motors.

 

[Evan@InglewoodTrans]

I still haven't had time to change Airdog motors.

By the time you get to log the new motor will be dead

 

[DMAXchris]

With my lift pump luck Evan, you're probably correct.

Is there any problem with doing the log in 4hi? I wouldn't think it would skew the results.