Turbo BS Thread

MAF sensors, absolutely. MAP sensors are based on BAR. Barometric pressure changes. Their resolution is based off of how many BAR they are capable of reading per a specified voltage.

1 BAR would be vacuum to Atmospheric pressure. 2 is above atmosphere. And so on.

Not by a flow through a cross sectional surface area.

 

Right, the sensor won’t care but the ecm’s load calculation is going to be way off now. It’s gonna need a lot more fuel for a given pressure with the bigger pipe.

 

I just figured out the third variable the ECM uses. Temp/pressure are from the MAP and engine speed dictates how much fuel based off that air density calculation. Correct?

 

Air temp could be on that pressure sensor or be its own.

You are correct though. The MAP sensor gives the load, then the rpm gives the speed. Then the VE calculations off of that, give the fueling necessary to maintain programmed AFR's.

 

If the main fueling is based off of the post TB sensor, then nothing changed, so that won't affect the tune. Having an increased or deceased load, based off of flow characteristics of changed parts, per rpm, will.

How flexible the OEM tuning software is, will determine how well it can adapt to changed parts.

 

Usually intercooler swaps are plug and play without a tune needed. Map sensors are bothered. Never seen a map sensor on a charge pipe before yet. Post a pic?

You will get more out of the intercooler if you have the car tuned

 

I am curious was TMAP stands for.

 

So the ECM doesn’t care about the size of the vessel supplying the air? If there is more air available to flow then so be it?

The only thing I’m curious about is why there are two sensors, one pre and one post TB.

 

That comes back to what TMAP stands for.

 

It’s what you were saying before, temperature manifold absolute pressure. The rear sensor doesn’t measure temp.

 

Temperature

 

I'm a bit behind, lol. Thanks for the photo. Never seen a map sensor in the charge pipe before. Do you have an electric bypass valve?

 

This is the first intercooler kit that replaces all the plumbing for this engine. Most intercoolers only replace the exchanger itself.

Yes there is a solenoid. I was just in the middle of writing my speculation about that.

 

Ok, well at least I have a better grasp of things going on with the MAP system.

I’ll do a bunch of logs before and after and look for any evidence suggesting that it’s leaning out and losing timing.

Thanks guys!

 

Random question: Does anyone have a stock intake and/or stock injectors laying around that I could borrow/buy? @JustDSM and I are trying to get a tune working for my turbo build but have run into trouble. He recommended swapping those items to get a baseline, but I don't have them. Thanks!

 

What kind of issue?

 

We are putting in known values like injector data, MAF housing diameter, etc, and getting very unexpected results. We're seeing trims with a sum total applying upwards of 50% correction. So, the thought was this: essentially turning the motor back into a N/A setup to run at idle with OE MAF calibrations and injector data to eliminate any and all ECU related issues.

 

It hasn’t been done, I’m probably going to sell it to move into something with four doors and don’t want to drop $1200 in it

 

@Hawk373

I run a VW 1.8t and have had it for years through multiple tune vendors. Currently it’s getting a bigger Holset turbo plumbed in.

As for the sensors and larger FMIC/piping, I don’t see it being an issue. My MAF, MAP, and temp sensors are pre throttle body. 20psi is 20psi, be it in a 3” IC pipe or 2” IC pipe because it still bottle necks down through the TB to the intake manifold anyway. The larger piping will make for smoother transitions rolling onto the throttle but all that air has to stop when the TB closes when getting off the throttle. A larger post IC pipe will cause a pressure drop which will also drop the temps some but not significantly enough to help HP wise.


Plug your numbers into this calculator as honestly as possible and have a look. Use maybe 5* degrees cooler than ambient for the IC temp and about 60-70% for efficiency. Water/meth injection goes a long way, too. Worth getting into that also. I'm looking at +20hp/tq gain just from summer temps to 70* fall temps in Southern Miss. I know it is a lot more peppy when it's cool out vs hot. Very noticeable when we get those 20* temp swings from one day to the next this time of year.

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

 

Need some good pictures of your engine bay. Need to see the MAF and vacuum hoses from both valve covers to the intakes.