99blkfrc99

I have a 99 and am looking into a 92/90 setup. I'm assuming I should also convert to a 5 wire 85mm maf. I can wire it up just fine but I have read you have to scale it in the PCM. The tuner I go to uses hp tuners. Does he have to scale it first and then tune or could I just wire it up and go strait to tuning??

enoniam

You can install it but leave it unplugged. The car will run in speed-density mode calculating airflow primarily via the manifold pressure sensor. It will throw a MAF code and light the service light after a few starts but should run ok for you to drive it to the tuner.

99blkfrc99

I get that but if I have the iat unplugged will it run really rich

96CollectorSport

If you are going to go through the work of re-wiring why not switch to the LS3/LS7 card style MAF? They are more cheaper and more accurate - you can pick the housing that you want to use.

We've had very good results with those in the past.

enoniam

No, your O2 sensors will adjust the fuel trims until you get to the tuner.

99blkfrc99

i did not know of that option. Could you help with a little more info on that set up? Thanks

tblu92

I once owned a 98 C5 with approx 475 crank HP----The STOCK 97-99 MAF is plenty large enough to handle up to 500 crank HP---There is NO advantage to going to a larger MAF unless you outgrow your current one---Basically unless you have boost beyond 6 PSI you would be best suited to leave it alone---There is NO HP advantage as the MAF is only a device that reads incoming airflow-No magic HP in a MAF
Your stock MAF table ends at 11250 HZ which can handle 500 crank HP
the newer years larger MAF table ends at 12000 HZ which is capable of almost 600 crank HP
PLUS even if you add the larger MAF to your car your ECM will still have a max of 11250 HZ----so you won't be gaining any MAF table
It is rather more complicated as other factors come into play as a larger MAF because of the diameter will show less MAF airflow than the smaller one did--making you think you may have some extra table However this always gives your ECM erroneous MAF readings and you risk of running your engine very lean at WOT---
You can fix this error ONLY with wideband tuning---to correct for the leaness caused by the slower erroneous MAF readings --This also takes hours and hours of data logging to correct not only your WOT fueling but all your P/T fueling--Issues like surging-dying and hard starting are always going to happen at P/T
Bottom line I would not do it unless you need to
PS anyone with a data logger can data log your ECM to se exactly where you max out at WOT on your MAF table--this info can determine if you need a larger one or not---and have to go to all the trouble of re scaling to a larger one

99blkfrc99

I guess the only reason I was going to change was to have a 4" intake pipe. But if the stock maf is good enough what would you or anyone recommend to connect my airbridge with the ls2 throttle body?

tblu92

On my car I installed an aftermarket air bridge and CAI that was also 4"
I had to do some custom fab work to make the stock smaller MAF bolt in---I used an adapter from 4-3 inches---If I remember I bought it from Air Aid however many companies make adapters I even think O-Riellys carries a line of them--

96CollectorSport

On one of the C5's that we installed a LS7 block with ported LS3 heads on we had lots of issues with the stock MAF reading accurately when we necked things down to the stock MAF then back up again to go to the 90 mm throttle body. MAF readings were much more stable and less erratic when we went with a strait 4" set-up with a card style MAF.

I never said that you have to go to a larger MAF to gain power - I recommend going to the larger MAF to get more consistent and accurate readings.

The smoother the airflow the better the readings are going to be - the newer MAF sensors are more reliable as well. I've replaced at least 3 of the older style sensors on various cars myself. I haven't had a bad card style MAF.

You do need to be able to re-calibrate the MAF tables so it knows that a larger housing is being used.

I would never recommend a ported MAF or any of those aftermarket gimmicks - I recommend a stock for stock replacement with updated MAF tables.

We have multiple race cars that have gone to this set-up because we need to make consistently reliable power - in NASA racing we have a power to weight ratio we have to stick within - if we go over we get DQ'd. Our dyno's numbers were more accurate after changing to the newer style MAF. One of the tricks we used to cut HP was to limit the amount our drive by wire throttle bodies would open as some sort of moving restrictor. This would allow us to make our allowed HP from 3800 RPM - 6500 RPM. Plain and simple the old MAF didn't allow us to make as reliable power number as the new set-up. But that's just multiple National Championship winning race cars - I'm sure it wasn't necessary and that it's all a coincidence.

99blkfrc99

Thank you. I've already talked with the tuner about it and he says it won't be an issue to re-scale and then tune. I appreciate your input. I've read you need the straitest pipe possible for accuracy and have seen guts put a screen or honeycomb in the tube also for accuracy. Is that what you have done?

96CollectorSport

On the LS7 car we tried to put a honeycomb in the stock MAF (it was on a 03 Z06 so the MAF didn't come with the honeycomb) to help get better readings but it didn't make a significant improvement.

Once we switched to the card style MAF we made a one piece mandrel bent 4" intake tube with the card style MAF in the middle of the tube. This way it was strait for about 5" before and after the MAF.
We had the radiator laid forward and the intake filter was in the drivers side headlight area.

On other cars that did not have the radiator laid forward we just ended up using the Halltech Killer Bee II system that was made for the C5 application and had all of the pieces for the conversion.

In either case the airflow is nice and strait and we see an improvement in MAF readings.

99blkfrc99

Is it beneficial to have the maf as close to the throttle body as possible? I was thinking of doing a coupler off the throttle body to a pipe with the maf. Then coupler and pipe to air filter. But if I do that it won't be the straitest possible because I will need a bend almost right away because of the clearance issues of the c5.

96CollectorSport

If you look at the intakes on any of the C6's with the card style MAF they are fairly close to the throttle body but I wouldn't purposely move it any closer. What you want is a smooth transition to the MAF sensor housing it's ok if there is an angle as long as it's smooth not a bunch of hoses and connectors cobbled together.

99blkfrc99

thank you for your input.

99blkfrc99

I purchased all of the necessary items to make this work. What do I need to inform my tuner to do to make this work for him? He uses hp tuners. Can I plug it in and drive it to the dyno or will it not run without tables being changed?

96CollectorSport

It may run but it's not going to run well, I would have the tuner install it or install it yourself at the tuners shop.

Since you already ran it by your tuner I'm sure he has a plan on what MAF table he's going to use.

romandian

so you have control over the throttle body? how do you do that?

tblu92

NO---Ideally you want the MAF location to be exactly where it was with the stock intake--Also you would want the orientation to be exactly the same--meaning if the pigtail is in the 1 o'clock position when stock you would want it to remain the same
If you change the location of the MAF from stock it will NOT read the same---Only someone with tuning software can take the time and do hours of data logging to correct a re positioned MAF--A mail order tune would be just "their best guess" which may or may not be accurat
It may seem to run OK being re positioned without re tuning but you won't really know unless it's data logged and you confirm your WOT fueling with a wideband 02---You may risk the chance of being LEAN at WOT which can cause engine damage OR very RICH which would leave lots of HP on the table and the resposnse would be lazy