I see. Glad I was not, am not and will never be living in the Republik of Kalifornia. It doesn't allow me to mod my cars, restrictions on guns and too many other whacky things. I suppose that if I lived there, I'd have to have an out of state registration or be stuck with what the factory gives me.

 

What does your scan tool show? On mine it's within 1° of ambient though does increase at idle.

There area where the air gets in is both above and below. Have you ever seen a picture of under hood airflow? Quite a bit gets in the front hood gap. Also I took a picture under mine:



Tube in the middle goes right to air filter from AO front plate kit. Again quite a bit of air flows in that gap.

 

Seeing as how long tubes are a proven .3 to .4 second gain in the 1/4. Your bet is wrong.

OP, imo, if you would be happy with up to 325 hp, bolt ons (new Runners.. ESPECIALLY new runners, after the long tubes..) will be fine. Edelbrock makes good runners, especially if you port them further, which is just time with your dremel, die grinder, and some good old elbow grease. Siamese your upper plenum, and port the stock lower (There are guys with over 300cfm with the stock lower.) Only if you can find a nice performance used lower, should you bother with swapping it imo.

Anything past 325hp, and in my opinion you are better off buying a crate engine, in terms of cost savings.
Why?
The 113 heads (which are the best stock l98 heads) are junk.
The cam is a broomstick.
383 stroker kit, to pump up past the lame 5.7 displacement.
New oil pump, QUALITY pan, pickup, etc
plus new gaskets, any relevant machine work needed to the block... All of this adds up fast. Crate engine will get you more power for less $ than DIY these days.

If I had to do my project over..I'd just have bought a crate engine myself.

 

Let's pretend you want to shoot for mod to mod vs dump a load on some crate engine:

1. SuperRam or MiniRam intake
2. Headers
3. Gears
4. Heads and Matching Cam
5. Custom Tune

Match the combo together as they're are many proven L98 combos out there but yes be glad your not in Cali like me. On my L98 I threw TPIS headers on it and woke her up, next would be the SuperRam.

 

Let's not forget that a good crate 383 with supporting mods like Tranny and D44 rear end if he is auto will rack up an easy 15k after all is said and done

 

UGH, to see someone go down this road again makes my head hurt. Sell, cut losses and get a built car if you want fun. Make it a newer one even.

 

Usually 30-50F higher than air outside the hood/car. I'm not sure what we're looking at in the pic, but my '92 has no ducting, porting or tubing from outside (in front of radiator area) to "inside" (on top of radiator shroud).

 

The pic is looking up in front of the radiator. Both above and below the filter there is about a half inch gap that's three feet long.

 

And that is stock, I'm guessing? My later car doesn't have anything like that.

 

You are under the wrong impression. The air dam and the radiator shroud guide "fresh air" through the radiator/ac condenser. But the radiator shroud itself, is what separates the air filter housing, from that same fresh air. The Air filter doesn't have access to that air, until it has gone through the radiator and has been heated.

At least in the 92^ cars. I'm not sure about the earlier, forward tilted radiator cars.

EDIT: I can take pics of my car if anyone is interested....

.

 

I agree with most of the replys on this topic. On my 90 L98 6 spd
i went with long tube headers, new timing chain this alone really woke it up! I did a A.I.R pump delete kit but all that does is enhance the under hood appearance. Once you cross the line on High performance up grade, you will always be tinkering and spending$$
They are not worth much but a heck of a lot of fun.

 

No Tom you are W R O N G

lets try and stay on point

the car in question is an 89, and like my 91 it clearly draws COLD air from in front of the radiator and A/C condeser

 

FROM WHERE!? Where does it "clearly" draw this "cold" air from?? You posted a pic -as if the pic shows it. I don't see any CAI in that picture What are YOU looking at?

I hope to god that you're not going to try to say that it all comes through that cut out for the AC lines...and that is your "cold air intake"

The OP's car may well be an 89...but the cooling package (and that fan shroud that you pictured), looks just like MINE.

.

 

While I've got no where near the experience with Corvettes as a lot of you do, from my limited experience, I agree with Tom. I had to replace my radiator shortly after buying my '92 coupe. That process involved removing the top of the radiator shroud. I was looking for where cold air could be drawn into the engine bay when I had it disassembled. I did not see anywhere where any significant amount of air could get into the engine bay without first passing though the radiator, thus heating said air considerably over ambient temps, just like Tom is saying.

Personally, I came to the conclusion that I would need to modify my air box so that it was inverted so that holes could be cut into it and the radiator shroud and the two connected so that air is directly forced from inside the radiator shroud into the air box to have a "true" cold-air intake on my '92 (no, I have not actually tried this).

You know? This has been bothering me a little bit in the back of my mind ever since I heard the Altima had an available 270 HP V6 as a engine option. And your comment was just what I needed to do a little investigation. Your assumption about the Altima being faster is incorrect. From what I read, the 270 hp 3400 lb Altima gets a 0-60 time of 7.1 seconds (C&D estimated the Altima would be at around 6.1 secs, but Car Connection actually ran the car and recorded speeds if I understand the article correctly). If the OP's '89 Vette is running properly, it should be a under 6 second 0-60 car. So unless you have a stock 84 or 85 Vette, or your Vette is not running properly, the Altima should not be faster.

http://www.thecarconnection.com/revi..._performance_3

http://www.caranddriver.com/nissan/a...-altima/379896

http://www.caranddriver.com/reviews/...leasant-page-2

 

Years back there was a thread with more of these pics:



As far as I know the air is from the from leaking around the fog lights, hood gap, etc. The pic shows no airflow backwards to the filter.

 

So it seems the stock intake/filter is actually a cold air intake .... No one should be surprised. Just about every fuel injected car GM ever built has the air inlet positioned in such a way as to draw the majority of air from outside the engine compartment.

 

It might if you go fast enough ...... in reverse.

 

http://www.waterpumpu.com/news-how-t...-operates.aspx

 

I apologize for not always understanding your humor.....This is not one of those times, instead I'm over here LAUGHING MY A-- OFF

 

But the filter is inside...the engine compartment. Inside. This isn't hard to see with eyes.