Well my car is back together and made the 2 1/2 hour trip to mph's dyno day. the good news is my car made 340rwhp and 350rwtq. the bad news is that the tune was way off so i have to do some data logging and send the computer back. the car has nothing but a set of tsp headers with magnapack exhaust and all the hand porting and polishing ive done. a/f was 15 to 1 till about 4500 and then 5000 to 6000 dropped to 13.2 to 1. the tuner runing the dyno and the tuner that tuned the car agree that my ported maf is flowing way more than the ones they sell to acheve this. and they agree that there is alot of power left on the table. so what i need to know is what parameters do i need to data log to get the tuner the info. he needs. i would call them but they are closed to day and i would like to get this thing data logged today so my computer can go out mon. thanx for any help. brett

 

Ttt

 

Ttt

 

Buy a scanning program such as EFIlive or HpTuners. Then it is pretty much a point and click on templates of scanning parameters. Data logging is fun..!! .

 

a friend of mine has a tech 2 so we used it today which give us an insain amount of info like every 50 rpms but i dont know what the readings should be so im just going to send all the info to the tuner.

 

just curious Brett, but how come you are sending your computer out and getting it tuned that way...I have been talking to a guy on here, Nick (BLOWNZ06) and he is from Knoxville, he is going to be tuning my car after I do my header installation. He is a ECS authorized rep and seems like a really nice guy. He's been tuning vettes for around 12 years now. Might be an option you might want to consider. Just thought I would let you know.

His site is: http://www.highpressuremotorsports.com/

talk to you soon
Jeff

 

The tune appears to be consistant with a closed loop value of 14.7:1 until PE (Power enrichment) cuts in at 5000 RPM and then a bit richer (open loop) to a commanded 13.2 to 1. This is how they come from the factory. The tuner will adjust the kick-in of PE utilizing MAP, RPM and % of torque to liven up the acceleration in WOT.

The LS1/Corvette setup produces the most power/torque at WOT with 13.2/13.4 until about 3200 rpm, then 13.0/12.8 from 3200 to 4400 and finally 13.0/13.4 from 4400 to redline.

I would think the tuner will want to see timing (including absence or exhibit of Knock Retard), MAF, rpm, MAP and fuel trims to determine what amount of compensation the PCM is applying in closed loop. One interesting thing, is if the PCM senses a lean condition, and has to add fuel to bring the AFR back to the stoich 14.7,:1, it also adds that percentage of additional fuel to the commanded air/fuel ratios in PE or open loop, making them a bit richer or "safe".

One thing if you could, would be to disable the MAF and let the PCM drop into Speed Density. From here the fuel trims can be monitored to allow "tweaking' of the VE tables (a fixed air flow rtable based on stock which is used if and when the MAF circuit fail) if he deems necessary. Depending on your setup, it may be as easy as pulling the MAF connector, driving around for 50-100 miles, then logging fuel trims against RPM and MAP. Talk to him about your setup or he may feel this isn't necessary with only bolt-ons, but if your airflow is increased as much as they think, it will help in the quick throttle transitional points.

Well as you see, you can go on an on and on....sorry

Good luck and let us know on the final numbers. My numbers were close to yours (see sig below) when Carmen finished the bolt on phase, but the tune really came to life with the torque, which after all is really what we are after

The WOT tuning is very difficult without a wideband and will be kept a bit conservative to be safe.

Ed

 

All your numbers are right in line. 340 horsepower is just what you should have for your mods. Your computer keeps your car at an AFR or ~14.7 at all times, except when at WOT. Like mowton said, your WOT AFR should be around 12.8 to 13.2. Unless they were talking about something else, I don't see where you have "a lot" more horsepower on the table. One thing I see is your PE should come in sooner than 5000 rpm.

 

I went back and looked at a stock 2000 tune, and it is a bit different than what I am used to in my 2004. PE enable is only based on MAP (15 kpa) and delay is set to 0 rpm and their is no PE rate table. So I am not sure why your pull up to 5000 RPM's is so lean? may be pulling a bunch of timing (knock retard) to compensate?

It's tough when you can't see inside. That is why I went and bought HPTuner, so I can work with my Tuner and "help" as I call it.

Ed

 

its not in closed loop and the a/f readings were at wot according to the tech 2. the computer is adding in anywhere from 10 to 18 % fuel on the long term trims so they just missed it in the tune. and i think i may be pegging my maf or map cause they are xtreme high 4.8s on both. there is no knock retard and no timing being pulled i have about 50 pages of info on the pull so surlly they can get it right. as far as why i did a mail order i figured with just these simple mods id get a mail order and when the blower went on id get a dyno tune.

 

Sounds good......does the tech 2 log the MAF Frequency? At about 7500 HZ, my H/C setup is 101 g/sec and 375 ay 11,500 HZ, as a point of reference.

 

what rpm is that at

 

as for where i got that there was more power on the table that was a direct quote from both the tuners that have seen the info. they think there is another 15 or so.

 

The MAF outputs a fresquency based on the amount (qty, density etc.) of air passing through it. It is not RPM dependant...merely defines the transfer function (calibration) of the MAF to that amount of air. You "tune" the g/sec value based on fuel trims or wb AFR % error at a specific frequency. A PID is available which will log the FT/WB at a specific received frequency. You only have to protect against entering PE.

I was asking as to see if the g/sec truely are much higher, based on your mods which would "saturate" the MAF. I wouldn't think so though .

Ed

 

at 2000 rpms a/f is at 15.2 to 1 @wot, maf 70 g/s, map 99 kpa or 4.75 volts
at 3000 rpms a/f is at 14.6 to 1 @wot, maf 125.03 g/s, map 99 kpa or 4.75v
at 4000 rpms a/f is at 14.1 to 1 @wot, maf 174.35 g/s, map 98 kpa or4.69 v
at 5000 rpms a/f is at 13.0 to 1 @wot, maf 231.98 g/s, map 97 kpa or 4.64 v
at 5500 rpms a/f spikes to 13.5 to 1@wot, maf 251.30 g/s, map96 kpa or 4.59 v
long term ft were at 10%

i do not pretend to know how to tune but i do know 15 to 1 @ wot is to lean the tuner runing the dyno aborted the pull every time it lean spike and it did it everytime at the same rpm (5500 give or take 50)

i think the reason they feel there is more on the table as far as hp is that it was still climbing when he aborted the pull the reason they feel there is more torque left on the table is that its 14 to 1 at where peak tq should be

it did make above 300 rwtq from 2000 to 5500 and i hope this is enough info but i honestly do not know thanx again if u can compair this

 

the reason i was impressed with the numbers is this is still on a ls1 intake

 

Well you are definitely not saturating the MAF, as I suspected. You would have to review the Power Enrichment table, injector duty cycle, O2 sensors etc. to really see whats going on.

Where is the AFR being monitored? You don't have any exhaust or intake leaks, do you?

I am sure once the Tuner gets into, he will find it.

Ed

 

the a/f was measured at the exhaust tip with a wideband that had just been calibrated. as far as exhaust or intake leaks none that i have found and ive been all over it. its my understanding that maf reads basiclly volicity and when u port it out u change the way volicity/ volume (more air at a slower speed) and that is where they think the tune is off. they think the maf is seeing incoming air at a certain speed and because that dia has changed the same speed does not equal the same amount of air as it did before it was ported or to the dia. of the plastic replacements they sell. now that they can see what the maf is reading and what the a/f is they should be able to correct.

 

sorry i lied about the knock retard i was looking for it up high and there was none. but from 1600 till 4000 there was as much as 3* at 1600 and it decreases till the a/f gets 14 to 1 at around 4000