Operation Overkill
 

........continues.
Experimenting with new MAF placement, directly connected to throttle body:





:awesome:

personally i don't think that's it's a good idea just for thet fact that in a maf sensor there should be the less turbulence possible, because it's a little thermistance in a round tube calibrated with the pcm...

that's why GM put a screen before the maf, to direct the airflow

I think that it will give you some funky reading but only when you go WOT or fully closed...

and in the event of a backfire you could damage it...


But with that said, the maf is located in the throttle on my 78mm TB on my L67

This is something that is so complex, you don't know how it will work until you try it out. I did one short test drive and was pretty impressed, but it may take many days for problems to show up.

The throttle body and especially the MAF are so far in distance from the intake valves that response always suffers a bit. I don't see how a backfire could affect them thru the SC and intercooler.

I did have problems with a de-screened ported MAF, it had no drivability at all -- constantly stalled. so I went back to the stock LS1.

The concern for it right now is more vibration and how to do the filter.

sorry i didn't tought about the intercooler.
That's what I need because i got some very high heat in my l67... 16 psi with no intercooler is pushing the limit a little and I'm killing the power by running an afr of 10:1 to be safe

Lookin good B! I am wondering though, having it that close to the blade would bias the flow readings. I know you are familiar with this guy, but Greg Banish told me to have a min of around 9" between the MAF and the TB. Gives the air room to smooth the flow before the body. Not because of distance from valves, but distance from MAF to body. Being that close together I can see how turbulance can occur in that short of a run between the two... just a thought though dude. On the other hand, if it works, then it works! LOL

Just had another idea though man. Dont know if I'm taking out my ass here but here it goes; Remove the honeycomb from your MAF. Then right before the MAF install a double size one. Instread if the 1" that is in there now, install a 2" even a 3". I bet that would be enough to keep the air flow straight all the way through the MAF to the Body?? Again, just thinking out loud dude...
Hey, as well, if your intrested in going to the card style MAF hit me up. I got the combo here right now that Im putting in mine. I can give you the part #'s if your looking to get the set up in yours, wink, wink...

Yeah, could use a flow bench right about now ................:)
It's difficult to interpret the results, since I'm altering the system that measures the airflow. I got a higher peak raw frequency reading, and less pressure drop on one test with the direct connection so far, but I need to retest it. The air at the supercharger inlet is turbulent to begin with, the vacuum gauge fluctuates at various lower RPMs. There could also be tuning effects depending on the blower RPM vs pipe length, who knows? But the only other choice is a curved tube between the throttle body and MAF, which also must be optimized. The best one I used so far is 45* bend, 3 inch diameter, flared at both ends. I'll try to post more later, short of time right now.:)

Any progress B? How's the set up working out bud?

i have no doubt he will get it fine tuned eventually !! post up when u get a chance

Thanks for the support, I appreciate it!

I have good news and bad news on these modifications:

The direct connection with the large TB and MAF appears to be a success. I measured about 3 inHg vacuum less pressure drop at the supercharger inlet, compared to a 65 mm TB ( ported stock) with a 3 inch curved transition tube from the MAF. That translates into about 1.5 psi peak at WOT, similar to going to a (0.1 in) smaller SC pulley. Keep in mind I have a 2.0 inch SC pulley installed, and before the mod was reading about 11 psi at the upper intake.

The MAF frequency and lb/min. were also an order of magnitude higher across the board. I did several tests on the street, and logged the changes in fueling seen by the PCM -- Injector Duty Cycles (IDC) and Injector Pulse Width (IPW) increased, and narrowband O2 readings stayed in a good range, no Knock Retard was generated by the PCM. I was now maxing out the 36 lb injectors at 12.0 Target AFR, and reset it to 12.5.

I went down to the track Saturday the 15th, (chomping at the bit, as you can imagine) On the first run, I did a good solid burnout, but the starter motioned me to halt and wait, I hit the brakes and waited a while, but then backed up and did another aggressive burnout (which ain't the best thing for a tranny :) ). I had a pretty good launch, no wheel hop, but out of first gear it hit the rev limiter, no WOT shift to 2nd gear . :lol: . The scanner threw a TPS code, and for a while I had some hope, so I put in a new TPS. Another run, same result, can't go higher than 1800 rpm in 3nd gear. So the search for a good local trans shop begins, and the necessary PITA demodding to facilitate a major repair. ( I can hear it now, "We ain't gonna guarantee this." :lol: )
(edit: still clinging to hope, a few more things to check out)

The other "good news" is this is an easy mod to try with the Magnacharger kit, or maybe extreme N/A builds, and might work just as well with a 65 mm TB and a stock MAF, depending on how they interface and what boost level you run. Also note, as run at the track, the air filter is bypassed, and just a short flared piece installed at the MAF inlet. You only need a vacuum gauge with an expanded scale to test the need for an upgrade.

Before we swing into sub-operation "Underkill", a final pic: :)

how do you know its trans issue and not something else?

Could just need more boost, maybe 13 psi is not enough. Might need a bigger blower.

Hey B, you get this fixed up yet?

No, it's at a transmission shop now, still in diagnostic stage. I could get it to run full tilt up to 72 mph if I left the lever in 2nd. If it could reach 85 or so, I'd probably have left it alone and just run 1/8 miles. ;)

And just when I had a little cash flow, too. :(

Sucks man hope they figure it out

Something about a second gear sprag blew up on it, I dunno about these things. He's gonna try to machine a piece from a turbo 400, if that don't work, go with a new stock piece. Raybestos Blue plates are in, and Alto steels. strengthen the TC. and then I'll need a good size jar of vaseline, from the sound of it :lol:

Nice Clutch Pack explosion, you done well. Killing a 4T45E isn't that hard though. Damn good when you got Turbo 400 parts hanging in there.

Ba-da Bing, ba-da "BOOM"!! You gotta' keep a parts list for us when your done man. I'd like to keep the 45E as well. If yours works out I'd love to get my hands on the list

Its thinking like this that gives the 45 a bad rep. They can hold a lot of power, people underrate them.