Help with relocating MAF

[BJM]

I have a 3" LT1 style MAF and I was planning to move it to the up pipe. I found a nice tight aluminum mandrel bend for a new pipe.

I know I have asked this about a year ago but cannot find the post. What size adapters do I need? I was at a shop that had 2.5 to 3" silicone adaptors but they seemed way to tight to fit over the MAF which is 3 3/16" . what have other people used here?

I was also wondering if I really need a plenum spacer to get this to fit since I do have a power plate which is about 1/8" thick and the extra gasket helps lift it some more.

How many people have done this?

 

[bruce]

Originally posted by BJM
I have a 3" LT1 style MAF and I was planning to move it to the up pipe. I found a nice tight aluminum mandrel bend for a new pipe.
I know I have asked this about a year ago but cannot find the post. What size adapters do I need? I was at a shop that had 2.5 to 3" silicone adaptors but they seemed way to tight to fit over the MAF which is 3 3/16" . what have other people used here?
I was also wondering if I really need a plenum spacer to get this to fit since I do have a power plate which is about 1/8" thick and the extra gasket helps lift it some more.
How many people have done this?

The 2.5 to 3" hoses I got worked.
I had to run a .5" to get the IAC to clear the in pipe to the turbo.

Becareful to get this right, losing a *pipe* and it will smack the hood. 2 cars local to me and I have done it. And another one in WI that I know of off hand. I've had more then just few people ask and do it, just didn't write them all down.

 

[TRiv]

Bruce, would locating MAF (LT1 style) at up pipe be better and easier (cleaner plumbing) in a two turbo set up as opposed to pulling thru MAF with two turbos? I am debating using two turbos though in my application it is somewhat easier than a single, using a TH3254-L transmission, the 84-7 GN driver header can not be used, must use Riviera DS header (hard to get and they crack worse than GN) and even if used have to fab a leak free crossover. Because of the engine bay room I have and motor/trans mid mounted (ahead of rear axle) simply mounting another 86-7 GN pass side header ( and turbo) to DS side of block makes it too simple. Also easy plumbing to separate ICs one on each side of car, ahead of rear wheels, my concerns are tuning to make it work rather than hardware.

I don't like the idea of pulling thru MAF with two turbos , just seems problematic that they would fight for incoming air, this seems more like trouble than using Riv DS header and Fabing crossover. The relocated MAF looks to be the best solution, only other concerns are O2 sensor(s) , and wastegate(s). Anyway, the relocated MAF would eliminate the above fear, and make for minimal plumbing in my set up, any thoughts? experiences? By the way, car is not really being set up for drag race, but road, transaxle not the best but only one out there that will work with Buick turbo6 and live ( I hope!)

 

[bruce]

Blowing thur one at the up pipe with twins shouldn't pose a problem.

The guy in WI is running his with a F/M, and has it below the 90d off the TB, and he's doing fine.

 

[BJM]

Okay, so I need the 2-1/2" to 3" adapters. Was it hard to get them onto the MAF? Is there a trick to it? All I did was hold it up to my MAF and tried to slip it in, it doesn't look impossible but certainly doesn't look easy.

 

[Phatman]

Bruce

Can you post your link to article...
TIA

 

[BJM]

Its on and working

I got the silicone adapters onto the MAF, I didn't think I could do it but I greased the MAF lip a little and struggled for a while. Anyway the car runs.

First impressions

Tip-in and responsiveness are only a touch improved. However I had spent a lot of time on the tip-in fuel (got a tip from bruce) and I had played with the MAF tables while everything was in the stock location.

Spool up is better. My car has a stock turbo, downpipe and converter if that helps anyone.

Previously in the stock location I would barely peg the MAF, even at 17 psi, now it pegs a lot more, its not making more power that I can tell but the fuel trims all moved around a lot and the MAF simply reports more air and pegs sooner. So I have to play with that. I used to have the BLMs all very well centered near 128. Now in the up pipe with just injector constant tweaking my idle (cells 0, and 1) are 145 and 128 and the rest have slid down evenly the higher the cell down to about 106 for cell 15. My idle seems less consistent than before for some reason which I of course do not like.

Overall I am neutral to this set up and might just swap back to see if I would really lose a lot. So far it seems like a wash.

 

[ijames]

I have a V2 front mount with 3" pipes from Jack Cotton, and I moved my lt1 maf to the vertical section of the uppipe in front of the radiator, using two straight pieces of 3" hose. They were awful to get onto the maf but we finally did it. I have the top of the maf about flush with the top of the radiator. That way there's no problems with iac and turbo inlet clearance or having to extend the maf wire (plus I've always thought that being that close to the throttle blade would cause either turbulence or uneven flow since at part throttle all the air is moving at the very top and very bottom of the pipe, so I wanted to be in a nice smooth, straight section). I had a bung welded into the uppipe a couple of inches from the hose to the throttle body for the mat, and that wire also reaches without modification. The boost gauge went up about 1 psi, spoolup is a little better, and I saw zero difference in mph at the track so I really don't understand why the boost gauge went up. BLM's and wot fueling basically didn't change, and while I didn't do any careful logging with ds I didn't feel any difference in tip-in or part throttle behavior.

 

[bruce]

Re: Its on and working

Originally posted by BJM
So far it seems like a wash.

Hmm, odd that the both of you didn't notice much of a increase in tip-in response. That's a puzzle.
But, at least you both did notice a slight improvement in Spooling which has been noted before.

Have you both 0'd out the MAF temp corrections?. With the later MAFs they do it on there own.

Now, if you were to populate the IAT table, and bias, I'd wager you'd notice that you can get rid of the season pinging, and other nuiances. Maybe, even move the IAT/MAT to the plenum, and get things much more correct.

Just thinking aloud.

 

[JDEstill]

Originally posted by ijames
The boost gauge went up about 1 psi, spoolup is a little better, and I saw zero difference in mph at the track so I really don't understand why the boost gauge went up.

Carl - it's due to the nature of our nonfeedback boost control system. When you set the wastegate at a certain point, it is similar to saying "ok turbine, extract X hp from the exhaust". When you moved the MAF from the compressor suction to the discharge, that lowered the compression hp required. With the turbine putting in the same amount of hp to the compressor, which needed less, boost and/or flow had to go up.

So you proved that it is more efficient with the MAF on the compressor discharge. If you were measuring your turbine inlet pressure, readjusting your wastegate back to your original boost level would show a lower TIP than before, and less backpressure is always better.

John

 

[Sleeper]

When I had moved my MAF to the up-pipe, I noticed an immediate improvement in idle, tip in response, and spool.
Instead of going with the hose reducer, I got a muffler shop to make me a 2.5" to 3 3/16" pipe reducer, that I cut and welded on to the end of a mandrel 90 deg bend. (I also spent some time with a die grinder smoothing the inside weld penetration.)
I made the MAF to TB transition using a piece of truck silicone hose that had been stretched to fit over a smaller hose bushing that sat on the TB. It was eventually glued together to act as one piece.
As Bruce had mentioned, initially I was plagued with blowing the up-pipe off. On one occasion it blew off at 24psi and put a dent in my hood Heavy duty T bolt clamps, and the glued piece solved the problem. (But a little too late )
I have since had to put the MAF back to the stock location because of the nozzle position of my alky setup.

Brian
I imagine because you had "fine tuned" your chip to suit your original setup, you wouldn't notice as much of an improvement as someone using a "stock or aftermarket" chip. No doubt, with some more tweaking you will be able to fine tune the new setup.

Paul

 

[BJM]

I should add a couple of things. My MAF is right at the exit of the IC, not at the TB about a foot away. I was not going to be able to get the MAF and connector from rubbing at the hood pad so I moved it to the IC position.

Up until late last year I did not know how to modify chips. I tried mocking up a MAF in the up pipe set up using rubber plumbing drain pieces and some exhaust pipe. At that time I had to jam the MAF almost right down onto the IC outlet which meant the airflow was mostly shooting through the center of the MAF not getting a chance to spread out properly. The BLMs were totally screwy and I couldn't get into boost without popping but man did the car feel responsive.

Since then I learned to program and after spending a great deal of time with MAF tables and tip-in fuel the car is a totally different beast. So I was quite surprised how little the up pipe thing helped. I remember bruce saying somewhere its amazing how nicely these cars can drive when set up properly.

The other thing is I have a V4 which has a much reduced pressure drop across it than a stock IC but without the large volume of a front mount and all of its piping. So I think my car does respond pretty well.

I "think" since my car was well setup and doesn't have the normal IC restrictions that the up pipe set up may not do as much for me.

 

[BJM]

Re: Re: Its on and working

Originally posted by bruce

Have you both 0'd out the MAF temp corrections?. With the later MAFs they do it on there own.

Now, if you were to populate the IAT table, and bias, I'd wager you'd notice that you can get rid of the season pinging, and other nuiances. Maybe, even move the IAT/MAT to the plenum, and get things much more correct.

I have definitely wiped that MAF correction table, its now full of code doing other things (but the table is disabled). I use IAT table with a boost sensing harness and change timing that way.

Since I can alter my wastegate setting from in the car I just toggle the boost down on cold mornings.

 

[ijames]

Bruce, I didn't have any tip-in issues before the move so I don't think it's reasonable to expect it to have gotten better. John, I believe everything you say but you haven't explained what I don't understand yet . My problem is that the boost went up but the hp didn't - that's what I can't explain. The way I think of the change is that I've raised the compressor inlet pressure by removing the pressure drop across the maf, so to get to the same boost gauge pressure I need a lower pressure ratio, or with the same ratio I get a higher boost pressure, assuming the turbine hp is the same (as you said). Oh, I forgot to add earlier that Cotton's 3" pipes fit the CAS V2 but you have to cut about 2" out vertically, or else you wind up with the bottom of the up pipe even with the top of the throttle body. I just cut a total of about 5" out to move the pipe down and fit in the maf.

 

[bruce]

Originally posted by ijames
Bruce, I didn't have any tip-in issues before the move so I don't think it's reasonable to expect it to have gotten better. John, I believe everything you say but you haven't explained what I don't understand yet . My problem is that the boost went up but the hp didn't - that's what I can't explain.

Did you happen to toss you WB, or EGT on it, before and after moving it?.
If the MAF was causing any signifigant restriction on the intake side then by moving it, it might have slewed the AFR slightly leaner, and/or the EGT.
For a 1 PSI difference I'd have thought there would be some evidence of something changing.

 

[BJM]

I think I got nearly a 1 psi change as well but the car felt the same. My power measurements were only seat of the pants though.

 

[bruce]

2 for 2, and actually 3 for 3, counting me.

I had to add more fuel, both in AE, and PE. But, I was using SD/MAF hybreed code, and with that I add it at the higher boost levels, rather then with the oem code, which just *hammers* the addition PE fuel.

 

[ijames]

No wb or egt data, but the O2's in directscan stayed about the same. I had tuned up to just below the onset of knock retard at the 2-3 shift, with 93 octane, so that dropping the fuel pressure or raising the boost 1 psi gave 1-2 deg retard where it was zero before, before the move, and after the move I still had no retard but moving the fuel or boost brought retard as before (whew ). It's like the only thing that changed was the boost needle. Actually the gauge went up about "2-3 psi" but i have since found out that that gauge lies up there. It's a cheap 30" - 0 - 20 psi and I was letting the needle go up to where 24-25 psi would be if the scale kept going, assuming it was still linear, but I checked it with another gauge (I finally installed my new 30" - 0 - 30 psi gauge and 3 bar map sensor logged with the lm1) and while 20 psi indicated was really 19.5, what I thought was 25 was only about 22.5-23. So I'm guessing the real boost went from about 21-22 to 23 or so.

 

[BJM]

Funny, I took out a little AE fuel. Have you ever tried Eric's MAF referenced PE fuel? I use it and its nice for saving gas. My PE ratio is 14.5:1 and I use the MAF to ramp it up to the full value only as needed. It nice that I no longer worry about TPS voltage having to hit some value to prevent knock.

You mentioned some speed density/MAF hybrid. I have been thinking of using my 3 BAR MAP sensor as a way of stepping of fuel once the MAF pegs, I was looking at my DS plots and my boost tracks the MAF reading really well, it appears I could simply crank up fuel ratio according to the boost level once the MAF reaches a high value.

This would be instead of using an Extender or using a full time Wide Band input like BoostKillsStress does.

 

[bruce]

Originally posted by BJM
Funny, I took out a little AE fuel. Have you ever tried Eric's MAF referenced PE fuel?

You mentioned some speed density/MAF hybrid. I have been thinking of using my 3 BAR MAP sensor as a way of stepping of fuel once the MAF pegs, I was looking at my DS plots and my boost tracks the MAF reading really well, it appears I could simply crank up fuel ratio according to the boost level once the MAF reaches a high value.

Nope.

At one time I was using the TL Boost sensing harness, and using the IAT/MAT tables for boost corrections. I used like 170 Gm/sec off the MAF tables and then added the rest with the IAT/MAT, boost sensing corrections.