In the Subaru world, we have a catalytic convertor in front of the turbo that restricts horsepower. Naturally, we remove those in short order. In looking at these ported maf ends, it seems to me that a similar obstruction exists in my LT1. I'm thinking it would be beneficial to do this mod in terms of power- as a sidce benefit, they're plastic, not metal which would lessen heat soak.

These are the ones I'm looking at: http://www.ws6project.com/user_stor/catalo...roducts_id=1804

Anyone have an opinion on these? Snake oil or simple, effective and inexpensive mod? (I know some people mod the stock one, but I'll be keeping the original parts original).

Here are my findings on this....

MAF comparison

I dont think I need to say how big this can of worms is. This has been a VERY debated subject in the past so everyone play nice please.

Hmm- I never searched, but should have. I think I'll give it a shot- at 65 bucks, I'll just return it if it does nothing.

Tyler, by porting the MAF...you gained an avg trap speed of 0.061 mph and avg 0.0799 seconds ET and lost 2 mpg in the process. You didn't test on the same day and tested at two different temperatures. The 2nd test with the ported MAF was done on a warmer day. The difference in avg times between the two days is probably due to better tire hookup on the warmer day. The 2 mpg loss from the ported MAF is significant.

The e.t.'s I posted were from the same day within an hour of each other.

Ok, within one hour, still...you stated that the temperature was warmer during the 2nd set of runs, and that means the test wasn't valid. Track conditions, and tire hookups are too variable. The difference between the fast and slow times at 104 mph is only 12 ft, which is easily within tire traction differences from run to run. Also, it takes between 20 and 200 miles for the computer to properly adjust to the modified MAF--computer changes from the "Integrator" to the "Block Learns". Once into the Block Learns, the computer will try and tune out the changes, which means essentially...zero gain.

Change everything else in the engine, but to change the thing that measures the actual airflow is counter productive.

The idea though is to remove a restriction. It still functions as a method of measuring airflow.

You missed what I meant. I meant it was warmer that day compared to the day I ran my quickest time,in my signature. As soon as I put the bored MAF back on the car ran quicker. That means there WAS a gain.

The problem is...the computer didn't have enough time to retune the engine. Still, a warmer day means a warmer track and better hook up for the tires, doesn't matter if it was one day later or one month later. The bottom line is that the test is invalidated due to different run times and the computer wasn't retuned--it immediately shifted to the Integrator as soon as it detected a change. The only way to properly evaluate a change in hp to these engines, is to use a properly calibrated engine and a professional dynamometer, and that means one at General Motors. Then the entire airflow must be remapped for the computer to respond correctly. In order to do this, think bucks, lots of bucks, BIG bucks.

To answer the other person's email, the stock MAF, no changes made, is not a restriction, it flows 800 cfm, which is more than is needed for even a 502 big block. A stock LT1 flows 490 cfm at 5,900 rpm and about 540 cfm at 6,500 rpm--the stock, 48 mm throttle body flows 615 cfm and 640 cfm with the airfoil. However, that flow is predicated on all 8 cylinders sucking in air at the same time. The actual flow comes no where near that. These engines are not rated the same way a carburetored engine is rated--the LT1 engine fills each cylinder from the intake plenum and not from the outside. Only enough air flows thru the MAF and TB to fill what was just sucked into the plenum. This only applies to the LT1 and not to the LS1.

There is no way a stock MAF, with any conceivable street hp can be a restriction. Your best bet, leave it alone. Don't believe me, well...it's your car, make the changes, live with it for a few months at $4.00/gal gas and see what you think. If you like it, leave it on, if you don't, rebuilt ones cost around $150 each plus the core deposit which will have to be paid, so make it something over $200. All I'm doing is presenting the info, the decision is yours.

Crimenies, all this old information repeated again and again and again, before I've even finished my morning cup of coffee...this is very hard on the brain.

I'm satisfied with the answers in the thread- a mod can lock this and I'm cool with it

As long as it's discussions, and NOT arguments....everything is fine. Just remember one thing if you don't remember anything else in this thread....


RESULTS WILL VARY!!!



Dennis

Well,actually the comparison IS valid. The e.t. in my signature was done with the bored MAF that had been run a FEW THOUSAND miles. So,the pcm was very calibrated to that MAF. Then,I reinstalled a stock MAF before driving to the TA Nats and left it on there for several months before getting runs in with it. So THAT was legit to. The fact that the car ran almost as fast when I put the modded MAF back on shows the pcm dealt with it fine. Tha slightly warmer weather could be why it was a click slower. Comparing the 2 fastest e.t.'s shows over a tenth improvment with the modified MAF. Sorry,but thats as legit strip test as your going to get.

I Have the ported plastic ends from my old Granatelli POS MAF sensor. The ends help, but the Granatelli MAF is worthless. It's justy a $300 set of plastic ends and a sticker! That's right, I said a sticker. Mine came off, guess what was underneath... a GM DELCO LOGO!!! It really didn't give me any help with power or times. When it died, I got a reman stock MAF from dealer, kept the ends from Crapatelli.

Actually, respecting jedimaster's request, and according to TFS Moderations rules, this topic will be closed. Jedimaster has had his question answered, has asked for it to be closed, and is no longer involved in the discussion. Thanks for the discussion everyone.

Dennis
Moderator