cudamax

Im with ya on the MAF Screens but since this started out as a cut lid on a stock air box didnt want to go there but that 50 bucks well spent and a lot better than the air filter lid

vette196

I believe the air mod discussion has peaked.

After reading the chevy article I was shocked at the gain from adding the ends

grandspt

I will add some info to the cold air mod. I have one of the plastic air filter housings which flips the air filter 180 degrees (Mid America Corvette used to sell them). This mounts to my modified radiator shroud which has a rectangular opening matching the air filter box. This allows cold air to get to the air filter at highway speeds.
It absolutely works (maybe not in a Dyno where there is no airflow but on the highway it helps), my friend also had a 96 LT4 stock while my car had the cold air mod. At an undisclosed airstrip we raced and I was able to pull him from around 60MPH on up. After that he bought the same cold air setup, we raced again but this time I could not pull him, we were always very close.
Cold air works at speed, more proof I had a 1983 Z28 with a ZZ3 crate engine, it had a drop base open element air cleaner. I installed the 5.0 liter H.O. dual snorkel air cleaner (it grabbed cold air from behind each headlight) at NewEngland dragway in the pits. I ran 2 tenths quicker and gained 3 MPH in the quarter mile. Hot air from under the hood does not make power especially if you have headers.

aklim

I'm a little leery about messing with the MAF. You could be sacrificing something outside of WOT for that 9HP. I'd like to see the before and after datalogs for that run especially outside of WOT conditions.

aklim

How did you account for the air quality change in the different days? A dyno run is pretty quick and does negate much of that between runs but different days can bring different air quality.

grandspt

I don't think air quality change at the undisclosed airstrip during our first five runs were important as I won all five runs. After my friend installed the same cold air mod we were pretty equal and I couldn't pull him/he couldn't pull me. So even if the air quality was different I should have still pulled him (assuming that cold air mods do not work)!
At New England dragway on my old Z28 it was the exact same day with the same temperature and humidity. It was 2 runs drop base air cleaner and another two runs with dual snorkel. Cold air works but it won't show on a Dyno, then again you don't race on a Dyno!
GM put cold air on 302 Z28s, Chevelle SS, WS6 Trans Ams etc. Mopar also had grabber hoods so it is a proven method of gaining some H.P.

Tom400CFI

OMG....DO NOT! Let BowTieGuy see this post. You guys are asking for it!!!

aklim

I would think they make large enough fans (they had fans on for my dyno runs) to blow cool air over the motor. While I don't race on a dyno, it does a decent job of removing variables.

As to cool air, I have a greenwood hood scoop. My HSR doesn't fit hence it was installed. I just did a test reading the sensors. In stop and go traffic, it heats up. No surprise there. I also parked it with the motor running to get it hot. Doing 40, it took more than 10 minutes to cool down even though I have a small cold air system because the slits in the hood sit in front of the conical filter. According to you, I should start reading cooler IAT but it takes more than 10 minutes (maybe even 20) to cool down to running temp from stop and go temp. Cool air was running over the manifold but the IAT sensor still released heat SLOWLY. If we were racing, you'd have won, taken my money and I'd be watching your tailights drive off before it cools enough to mean anything.

Tom400CFI

Aklim, like many things C4, it totally depends on the year. Your car is/was TPI, I believe....if so, your IAT is in the plenum and I'd guess is affected by the temp of the aluminum it's screwed into....and that could take about 10 min to cool.

LTx cars IAT sensors are screwed into the rubbery snorkel that spans from the TB to the filter housing...so in that case, IAT's are fairly "real time".

JrRifleCoach

Average hp for a l98 is 260hp. Add, lets say 1% at WOT.
I completed most of these 1% mods on my 86 and nothing gained hp like replacing the cam..
Like I said earlier, these are great mods to acquaint you with the car.

cudamax

Ya a cam will do a lot. Kinda like the Prom of the motor.
Wait, just wait til ya replace the junk factory heads and exhaust and start playing with Intakes, then dial it all in

grandspt

😁 I know!

grandspt

I am not arguing with your results, But LT4 motors do breath better than L98s hence the higher redline. Also the faster you go (I had said in my previous post I pulled my friend around 60MPH and up) the better cold air works. So 40MPH might not be enough to see any gains.
Good luck!

1994BlackRose6spd

CaliC4,

You are not going to get much/any positive reinforcement for small modifications or bolt-ons with this group. Mods like these may make a 0-1-2-3-4-5 HP increase somewhere on your power curve.

The fact that you notice it but are having a difficult time telling if there is much of a difference should reinforce the 0-5ish HP difference.

The LT1 in the Corvette doesn't seem to have the same bolt-on opportunities as the F-Body or the old pushrod Ford Mustangs. The exhaust and intake are already fairly optimized. The water pump isn't pulley driven so you don't get the same HP bump by going to underdrive pulleys and slowing the water pump down a bit (vs Mustang). The OptiSpark isn't able to be manually adjusted like an old 5.0 pushrod mustang. We used to just grab those things and advance them 4 degrees BTDC initial timing after disconnecting the computer if they would take it with premium fuel.

Unless there is an issue where you are now sucking in more hot air from the box by cutting the lid (getting more underhood/hot air than fresh air) it "should" be better. I am not that familiar with where the air comes from since I have only had a C4 for a month. I say go for it and while you are at it put the Air Foil in Maybe get one like the Holley piece on Jegs? One that doesn't have a screw or bolt to come loose or pieces that can get into your intake.

sluggballz

I've had my 95 convertible for a little over 6 years. I saw this article after I had my car about 6 months. I figured it seemed like a few inexpensive and easy mods to make. I took the screen out of my maf, cut the air box lid and did the coolant bypass. My sotp dyno wasn't sensitive enough to tell a difference, but there was a little more growl at wot from the engine bay. Last year I put in shorty headers, my stock exhaust manifolds has cracks in them and sounded horrible while setting at idle as well as I didn't have the budget for or the want to mess with the cross brace and long tubes. I also put on muffler deletes.
No dyno runs, before or after, with all of my researching around the interwebs, I think, THINK, I might have picked up 8-12 hp. Big difference? Nope. Cheap horsepower? Pretty much, with the headers and muffler deletes, I spent about 350$. Plus I did all the work myself. It's a fun car to drive and I've had no ill effects that I can tell from taking the screen out. She has 130k miles on her and still broke the rear tires loose the other day shifting into second from a standing start( just out having fun and celebrating hitting 130k).
To paraphrase yoda, there is do or do not. Do it or don't. But enjoy the car for what it is, a fun driving machine!!

aklim

Isn't that why they relocated the IAT to the front to get a more "real time" temperature or to fool the ECM into enriching the mixture? I do wonder how much effect it really has since the air has to be heated up by the time it gets to the cylinder since it passes through the heated manifold. Had a buddy that got a little bit more to break a personal barrier by laying a bag of ice on the intake till he was about to take off.

aklim

It took, IIRC about 20 minutes to cool down the intake going at 40 to what it was before I heated it up. I did some trials with the IAT to make sure it was reading with the CTS at startup, when I it it with a thermometer when hot, etc. At higher speeds, it will cool down the intake a bit faster. IDK. Like I will admit, the theory sounds nice but how much practical advantage will be costly to determine for the average car owner. Certainly affordable by the manufacturer but I suspect, it won't show much practical gains hence the lack of test data supplied.

aklim

Don't know what shorty headers do for an LT. IF you got 8HP it would be cheap power and "IF" is the operative word. As to what happens with you take the screen out, hard to say without "before and after" datalogs. Personally, I would only descreen my MAF if the car was being tuned to be absolutely sure it is accounted for. To me it is kinda like advancing the timing. It might give you gain here but if it pings there, the ECM may retard it even more. BTDT when someone screwed up my timing royally

Tom400CFI

I don't think the air heats much in the intake. Maybe it heats a little more in a TPI than an LT1 b/c it's a larger intake path, but how long is the air IN the manifold at WOT? Each cylinder tries to ingest .5 L every 90* of crank rotation....the air ain't in there very long.

I'd GUESS that GM moved the IAT to the snorkel on the LT1 b/c it was a more accurate representation of actual air temp than the plenum mounted TPI which maybe have been (and sounds like it was, based on your comments) measuring aluminum plenum housing temp.

Whatever the case, I doubt moving the IAT makes much of diff.

cv67

did all those "mods" car didnt run any faster down the track

Prior owner descreened the maf could never figure out why it would randomly go dead lean...eventually cost a head gasket. Dont do it that screen has a purpose, just cause someone said in a book it gains XX in 1990 doesnt mean you should do it.