It seems to use the value in the last column you were in before you jumped out of the map if you don't jump dramatically outside your max load cells.. Since It would pull serious timing BEFORE I rescaled the map to 320... I suspect there may be an algorithm that determines how much outside your load axis you are, and may use the boost cut algorithm...

 

MalibuJack,

If you are curious as to whether your blow-through is calibrated to the stock Maf, why not just install both at the same time? Hook up the stock Evo MAS, do a few pulls and log, then hook up the blow-through GM MAF, do a few pulls and logs and compare.

Use jcsbank's equation since that follows the mass airflow.

Also, to address your question a few posts up: The load really shouldn't dramtically be different between a small turbo and a big turbo at 22 psi, unless one or the other was dramatically outside of it's efficiency range at that boost and RPM. If both turbos are around the same efficieny rating at those conditions the load would pretty much be the same.

That's actually another sanity check to see if your blow-through is calibrated correctly.


Eric

 

I was getting into the 240s on 1 bar of boost w/ the 35 once tuned half way decent. I have been busy with work, but I am going to try to nail down 18-19 psi solid and see if I can get away with that on the stock injectors. As the car sits now it will spool up to 18 psi and then drop to about 16. The turbo hits pretty dang hard with this setup and the torque hit feels stock turbo-ish but a little more blunted and moved up about 1.5K rpms. In 3rd, its pulling hard from 4.5k on up.

The ECu runs in the 260s around peak tq with the boost hitting 18 psi. I'm only scaled to 300.

I'll keep testing and responding back...its going to be a bit slow though as I'm doing my OB/GYN rotation right now and 13+ hours of work a day leave me a bit tired. Map to come once I'm comfortable and feel that most load ranges are accounted for.

 

Okay, The first problem is I cannot install both at the same time, My blowthrough setup is a plug and play replacement for the MAF, Also, I loaned my stock MAF to a friend and haven't gotten it back yet.. No excuse of course, but Its just not really possible.

Your other point, well, 22psi on a 16g turbo is SIGNIFICANTLY different than 22psi on a GT35r.. The pressure is the same, but the Air Mass its moving is different Thats pretty clear regardless of calibration.. Regardless of efficiency range, the CFM ratings of the two turbos are quite a bit different, so I can't really use my old data logs for comparison.

I'm using the calculation, thats how I got the 330 number.. It was a momentary spike to that cell, Generally it was 300-310 under load.. That does sound pretty correct according to others data.

I have two issues that I'm chasing, so I want to make sure the MAF isn't contributing to it.. I have a small exhaust leak around the vband seal at the turbo to O2 housing (its a vband clamp not bolted up like other T3/T4 style turbos) And I am getting a bad misfire at higher RPM.. Either their both related, or unrelated, but I am getting knock and I suspect its one of those two things.. Unfortunately I'm not running aggressive timing, or very lean, so I have to resolve the two issues and then verify my exhaust isn't rattling again.. I have to resolve these issues before I can tune the car any more, no point in tuning around a problem..


On a side note, I had some fun with a brand new Z06 today even with the tune the way it is at 19-20psi I gave the guy a good run, misfiring and all..

 

You have a GM MAF right? I don't mean to have them both hooked up at the same time....I mean to have them both installed at the same time, so that you can simply connect one or the other between pulls.

I haven't seen your setup, so sorry if I'm way off, but when I had a blow-through setup on my Eclipse I could do just this. A lof of people with DSMLink used that method to calibrate the GM MAF/ Maf Translator when it first came out.


I would agree with you at 22 psi with a 16g. I was thinking more in terms of lower boost, where the efficiency of the two turbos would be nearly the same (I don't have both maps in front of me right now). I was basically just trying to say that at the same efficiency a small turbo will flow the same amount of mass airflow as a larger turbo. The divergence comes once you start spinning the smaller turbo out of efficiency and start propducing more heat, resulting in a much lower mass airflow than a larger turbo at that same psi. The CFM ratings of a turbo are usually just given at a PR=2 and the last efficieny island on the compressor map, but as you know, means nothing. You have to take into account the displacement of your engine, VE, and RPM to find where your engine falls on that map.

Again, I'm not trying to say that you don't know this...I'm just throwing things around to try to help out in any way that I can.

 

Its a ford cobra blowthrough sensor, and yes, I have in the past done the swap wiring thing, with the stock turbo it was alot easier.. Only its not really that easy with the new setup, I have a 4" intake on the car and would have to swap the intake, put a recirculating DV back on (I have another HKS SSQV with recirc on it already for this reason) but its not very convenient to do, I keep the parts in my trunk just in case I have a failure that prevents me from driving the car with the blowthrough. But I loaned my stock MAF to a friend and haven't gotten it back yet so its a moot point anyway.

I'm almost there, it seems that some of the other GT35r guys have similar readings with the stock MAF so I'm not that far off.. Just have to fix my glitches now and look at my ignition system just in case..

 

Car really woke up when I stepped up from WG pressure (1 bar) to 18 psi. The car is finally starting to impress me some. AFRs with the stock injectors look great as well. About 12.0 or so up to 10-11 psi and it tapers from there as boost and rpm increase to low 11s. I have a strange rich spot b/w 3 and 3.5k rpms during spool up that goes into the 10s that I'm having some problems tracking down. Fuel maps are fine throughout those load ranges and leaning the hell out of the maps in those areas seems to make no diff. Any ideas?

As mentioned in the other thread, I'm on the stock MAF and with 18 psi my load is getting into the 260s quite consistantly.

 

Thats possibly the accel enrichment table... I see that too on occasion..

 

its an RNR gt35r kit .70 cold side/.63 hot, 1000cc RC injectors, standard turbo manifold w/ tail 38mm WG.

I don't think I'm going to be installing it though, after some research I think it will just be too much power for me.

 

So average load at peak torque on the STOCK motor, with a 35r is around 300?

 

It seems that way.. 300 or so seems to be the magic number for pump gas boost levels..

 

Isnt Trinababe running the Stock bottom End and running 28+ psi and running it fine ?

 

Yes and run personal best of 11.1@128MPH with ingnition breakup.He is running mentahol now on stock block!!He should run some 10.??@13?MPH next time after a lot of preparation.

 

Since im taking my head off, im thinking of doing a head gasket spacer and rod
bolts while im at it. Pretty much ensure all the weakends are somewhat rilable for the power that im going ot be pushing.

 

I currently have a 35R with HKS 280s and using stock block and head with exception to springs and retainers. I am using ecuflash with a base map and street tuning. The biggest issue I have is the lag and getting it to make better or more power through the midrange and top end.