Extended MAF readings?


Just another Tim ;-)
I am just wondering what kinda #'s you guys are seeing on your MAF with translator and extender. I am getting low 200's with the highest ever being 213. This is at 16-17 psi boost.


–M+M 3’ MAF/Translator/extender chip
-65mm TB
-Weber 201/201 billet
-T+D roller rockers
–Port matched intake
–Full port/polish heads/1.77-1.50 valves
-60-1 (stage V) BB Turbo
-ATR Exhaust/Straightline Perf. Muffs
-AC 3k Lock up
I was going to say "holly cow!!!" huge numbers, I can just barely get over 180 at 26# of boost, then I looked at your setup.

That is a healthy breathing motor!!
Your supposed to double the translator numbers if you want to compare them to stock MAF numbers correct? So 200 on a translator would be 400 on a Stock GM Maf scale that would max at 255?
Correct Mike. SO if I was comparing to stock I would have a value of 426 as the max, however comparing to stock flow isnt really telling anything since most should be pegging the 255 mark rather quickly :)
I went to the track last night and I ran 20 psi boost so I figured I'de come back and update this. The MAF readings are maxed out at 254 through the entire run. Man this car runs strong.

1st run, 16psi boost-NO TIME??? apperantly the timing tower wasnt ready for racing yet :(

2nd run, 16psi boost in 1st and about mid 2nd gear I turned the BSTC up to 20psi.

11.91@115 1.76/60ft slight traction problem

WoooooHooooo my first 11 sec. run :D

3rd run, I left the BSTC up in the 20psi range for the entire run. All I wanted to do was back up my previous run with another 11.xx

11.67@117 1.77/60ft spinning and grinning through first.

Needless to say I AM STOKED :cool:
This doesn't make sense to me...

If you are running the extender chip, and you are maxing out the air flow reading with that (ie scan tool reads 254 gm/sec = 508 gm/sec in real life) then you ought to be running faster than 117 mph. I would expect that air flow to put you around 550-650 hp, and closer to the top of that range than the bottom. Which would then put you in the mid to high 120's in trap speed I think. Look at TurboDave, he's running about same trap speed with a 180 (x2 = 360 gm/s) reading.

Are you sure you have the dip switches in the translator set right?

My switches are set to on, on, off, off. Maybe with some more info it'll make better sense.

The tires I am running are Hoosier Quick Time Pro's 26' X 9'. I was sideways pretty badly (rear out to the right) in first, then in second it kicked out to the left. I was working the throttle alot with most of first and second being under 3/4 throttle. I didnt go WOT until after the 2-3 shift and then at about the 1000' mark the shift light started winking at me so I shifted into OD, then of course shortly there after the converter locked up which caused a few deg. of retard. Vehicle weight is approximately 3850-3900 lbs.

A Quick trip to the horsepower calculator came back with @480 HP at the wheels and @600HP at crank so your numbers don't look too far off:)
On alchy and 23# of boost with street timing I am seeing a WOT average of 185 and a usual max of 189/gps with the Translator + and 3.5: LS1 MAF. I just love this setup!
Originally posted by JDEstill
This doesn't make sense to me...

I would expect that air flow to put you around 550-650 hp, and closer to the top of that range than the bottom.

John, he left out that this was with a street 93 octane chip and 93 octane pump gas + some xylene, maybe 96-97 octane max. He got a little leaner than I like to go, but even so with the lower timing compared to DH his bsfc has to be off a lot, maybe .5-.55? What does that do to your numbers?
Another question.

What translator version?
What MAF Base setting?
What MAF WOT setting?
What Extender chip number?

Yes, the numbers sound high to me too.

I did swap back to the alchy chip. 23 degree low and 21 degree high. It seems to pull considerably harder with this chip.
What translator + version? = 4.2
What MAF Base setting? = 5
What MAF WOT setting? = 5
What Extender chip number? = BYL57C0A

I recently swapped from a regular trans to this trans+. The chip I am currently running was made for the older trans.
Also the converter seems loose to me. Art Carr 3k stall. Flashes at the line to 3600rpm and then only goes up from there. RPM's at shiftpoints are between 5700-5850. After shifts they drop to 4700-4800 which is spinning too fast for my liking. I did get into the Yank GP on LS1.com (Thanks to Bob :) ) so I have a GN Turbo Thruster 3000 on the way which I am hoping will lower my RPM's throughout.

If anyone want to see a DS file let me know and I'll shoot it your way. If there is something wrong and I can get her running better it would be great, however, it is running awsome now and if it gets much better I will probably soil my leather seats:D
Originally posted by ijames
He got a little leaner than I like to go, but even so with the lower timing compared to DH his bsfc has to be off a lot, maybe .5-.55? What does that do to your numbers?

510 gm/sec air = 4047.6 lb/hr air

Assume a/f ratio = 12:1

4047.6/12 = 337.3 lb/hr fuel

Assume BSFC = 0.5 lb/hr-hp

337.3/0.5 = 675 hp

At a BSFC = 0.7 it comes out to 482 hp. Seems to me like you'd be leaving a lot on that table with a BSFC that high. BTW, you'd need 55# injectors at a minimum to flow that much fuel, something in the 65-72# range would be much more suitable.

You have mail :-)

Your way over my head with the number crunching your doing. All I know is what DS is reporting and if something is out of wack I have no idea what it could be.
Some further discussion.

Well, setting the MAF WOT switch to 5 will increase the
MAF reading.

You are running your injectors static....., at times WAY past static.
So a couple of things......

Have you looked at your plugs? Do you think you are richer than your O2's show?

Try setting the WOT switch to a lower number, it will bring the MAF numbers down.
That particular chip is programmed fairly rich, you should be needing to reduce fuel,
not increase.

Did you run the translator on the same settings for both the runs you sent?

Have you checked your fuel pressure at WOT?

You may be losing some mph in that loosey converter. Maybe you should
hit the clutch sooner.

Sounds like it's running pretty well though.

How do you like that BB 60-1 turbo?

(edit for content)
Tim -

Sorry to confuse you with the numbers! Just trying to do a reality check.

In a nutshell, if you are moving some quantity of air, you need some amount of fuel to go with it (which gives you the air/fuel ratio).

That amount of air and fuel should make some amount of horsepower.

The amount of hp you get out of that air/fuel mixture is the BSFC, brake specific fuel consumption. In other words, how many lbs of fuel does it take to make 1 hp?

You think you are moving ~510 gm/s of air, if the extender chip/translator is working as it should. That amount of air, with the right amount of fuel, should make between 480 and 675 hp, depending on the BSFC (or lets call it the efficiency) of your engine.

If you have an inefficienct engine (really rich, wrong timing, bad heads, lotsa things could be the problem) then you'd be at the lower end of the scale, BSFC ~ 0.7, and about 480 hp.

If your engine is pretty efficient, right a/f ratio, right timing, all the stars are lined up, etc..., then the BSFC ~ 0.5, and you would be at the high end of the scale, maybe 675 hp.

Or you could be somewhere in between (most likely). That's where my guesstimate of 550-650 hp came from.

It's just a reality check, to see if you are making a reasonable amount of power (and getting the appropriate mph) from the air you think you are moving through the engine.

It just seemed to me that if you really are moving that much air then you should be making more power than you are, unless your engine isn't doing it's best for some reason. Or the other possibility is that the air measurement is wrong, which would lead us to a problem with the translator or extender chip.

I'm leaning toward the measurement being wrong, because I think it is tough to move that much air through a 231 cid engine at 20 psi boost. Not saying it's impossible, but to do it you've got to either being revving the engine higher than typical (over 6 grand I'd guess), it happens to be really cold out and you've got a great intercooler, and the volumetric efficiency of your engine is really awesome (great heads and cam and low exhaust backpressure). Or all of the above together. Again, not impossible, just unlikely.

That help?

No, I havent looked at my plugs.....Yet.

The Base and WOT settings were changed netween the two runs. The 93 chip run had a base of 3 and WOT of 3. My BLM's were kinda low idleing so I changed the base to 5 and upped the WOT to 5 to make up for the difference in the base setting change. Does that make sense. I think that changed the overall by 1%+ I will try some lower WOT settings and see what kinda numbers that shows.

Fuel pressure has been checked and is increasing as it should.

Hit the clutch earlier?? I havent hit it at all yet :) I really dont want to either since I have a Yank on the way I dont wanna hurt this one prior to selling. I did pick up some taller tires (275/60/15 BFG Drag Radials) that I am going to try and see what kinda RPM's I get.

As for the Turbo.......I am in LOVE!

Yes, that does clear things up alot. That coupled with what Bob has said leads me to beleive I am making it read that high because of the settings in the trans+. I will try some other settings and see what happens.

Thanks a bunch guys!

Using 117 mph I estimate 480 rwhp average, assuming 3850 lbs total. Using a typical 25% loss in the trans gives 640 hp average at the motor which is in line with your estimate based on airflow. It all seems pretty self-consistent.

I've ridden in that car, and it spools so fast it's beyond scary. From a dead idle move your right foot from brake to gas-pedal-to-the-floor, and it's over 10 lbs of boost at about one-Mississippi-two-Mi-spooled Also, my PTE54 spools slowly from 0-5 psi, more quickly from 5-10 psi, and then from about 12 or so on up it just winds around in a fraction of a second. Tim's goes from 1 psi to 20 psi as fast as mine goes from 15 psi to 20 psi.
Hey Carl, maybe I'm the one who is confused :)

I'm looking at Joe Lubrant's handy spreadsheet. For 118 mph and a 3700 lb car he shows 470 hp. This is consistent with the other hp calculators I've seen. I thought this was flywheel hp though, not rear wheel hp.

To check, the inj size he shows is 39 lb/hr @ 100% duty cycle. 6 x 39 = 234 lb/hr fuel, and with a 0.5 BSFC you get 468 hp, which checks.

If the hp he lists was rear wheel hp, you'd need 625 hp = 312.5 lb/hr fuel = 52 #/hr injectors @ 100% duty cycle to get enough fuel to run that number. Which doesn't seem right to me...

So, I guess the confusion in my mind is whether all these hp calculators are spitting out rear wheel hp or flywheel hp. Ideas?