Alright i know this has been posted before, but i dont know the names of the posts and can't find them so i'll just post it. I am looking for a 89-92 350, I prefer an iroc. Has to be a 350, though. I know the diffs in HP, but like in 90 they switched to Speed Density on the iroc. It added 5 HP. But you know how some people replace the MAF for like 20 HP or somthing like that? Can you do that with a Speed Density System? I also have read that the newer 3rd gens don't respond to mods well. I am planning, exhaust, headers (prob), chip, fipk thats al i can think of now. What is the best to get etc. thanx, first post here

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no car, just savin for a fbody, i am 16 not to much money, I am shooting for a late 80's early 90's 350, iroc or z28.

[This message has been edited by jdhommert (edited December 03, 2001).]

 

I'm sorry man... but....


HAHAHAHA

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1985 Iroc-z, 14 second 305, new engine in the works.

 

Anywho....

there's no MAF on speed density, thats the whole Idea

As far as responding to mods....
I'm sure the boys in the DIY PROM board could straighten you right out on that one

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1985 Iroc-z, 14 second 305, new engine in the works.

 

i know that, they switched over from MAF to Speed density. What i was tryin to say was when people have a MAF, sometimes they replace it with a better one. I was wondering if you can do that with a Speed density (replace it with a higher performance one). Exactly how does speed density work? Is it possible to get a better one? etc.

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no car, just savin for a fbody, i am 16 not to much money, I am shooting for a late 80's early 90's 350, iroc or z28.

 

Hey man! Glad to see that you have such an interest in the F-Body! I understand that you are just getting into this, so I will try and be as gentle as possible here.

You are correct in saying that they switched from MAF to Speed Density. They did that in 1990 if I remember correctly. Speed density does not work in the same method as the MAF cars, and there isn't really anything to upgrade as far as that goes. The reason is that the MAF sensor was/is part of the air intake system and the guts of the MAF were very restrictive. That is why people upgrade or modify it themselves, to get more air through it. The speed density cars don't have the MAF and thus the restriction is gone. For more info on that topic, look up MAF vs. Speed Density or something similar.

I to have heard that the speed density cars don't respond as well as the MAF cars to mods, but I have no experience with that, so....no comment.

At this point, my advice to you would be to find a car that you like right now. I don't know that I would focus on what car has the best intake or whatever quite yet. I mean no disrespect to you by saying this, but you have much to learn about these cars, and it is best to start slow and don't get in over your head. Get the car and start out by doint the simple things like a tune up, oil changes etc, and while you are doing these things, take a look at where things are and begin to get a feel for the car. Get it running the best that it can before starting down the mod path. Afterall, I was, as we all were, once where you are at and it can be overwhelming.

Oh yeah, get a shop manual, like Chilton's or Haynes and start reading. You would be surprised what you can learn from one of those things. That is what I did to begin with and when I started messing around with mods, it became handy...as well as all the friendly people on this board. Good luck on your hunt, and please post questions if you have them...that is why we are here. Later

Matt

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irocet@hotmail.com

drive.to/Stang_Kilr

88 IROC-Z -- 350 L-98, 700R4, Flowmaster, Edelbrock Headers, Catco Cat, K&N, MAF Sceens Removed, Airfoil, March Pullies, Comp Cams Magnum 1.6 Roller Rockers, Bosch Platinum Plugs, Accel 8.8 mm Wires, MSD 6AL, Hypertech Cap & Coil, Hypertech Chip, Hotchkis Strut Tower Brace

 

im not a brand new guy to camaro's, i am kind of new as i have been heavily researching them for about a year. I just don't know much about MAF, or speed density (especially speed density) Its cool though not mad your cool thanx for help, keep the posts comin!

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no car, just savin for a fbody, i am 16 not to much money, I am shooting for a late 80's early 90's 350, iroc or z28.

 

...

 

MAF cars work by actually measuring the amount of air going through the MAF. Speed density cars have no MAF but instead measure the manifold pressure (actually the amount of vacumn) and then also check the throttle position and other variables.
Each of the systems rely on the O2 sensor to adjust the amount of fuel that is injected during part throttle.
My car is a speed density and it responded to mods without continually making changes to the prom chip. A MAF car might have responded a little better???
Which system is better is a toss up and IMHO it is not worth changing a MAF to a Speed Density or vice versa.
One thing good about a a speed density system is that you never will have to replace the MAF sensor since it does not have one.

 

I know I'll sound a little biased and I'm almost affraid to type this for fear of ruining your post, but I wouldn't rule out 305 TPI 5 speeds, the SD(speed density) versions gennerally run mid 14s in stock trim and any (SD or MAF) has potential for high 13s,low 14s with minimal mods.
I also think it's kinda a myth with that our cars don't respond well to mods, they do if you choose the right ones. I've picked up a full sec et and 6 mph for about $700-800 of performance mods(headers,cat,chip,air filter).
If you're not looking to put on aftermarket heads(the only drawback on a 305) then I don't see why to steer away from a 305 5 speed. Just might help you search for a car.

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14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

The switch to Speed Density over MAF in 90 had absolutly nothing to do with the 5 HP increase. The same year as the switch, (which was done because SD was cheaper to produce over MAF, not better) the L98 got lighter weight pistons that were responsible for this 5HP increase from its compared 240HP in 89 to 245HP in 90.

MAF and SD both have their advantages and disadvantages, and I could go into this but all u have to do to get more information than I or a few could probably give at 1 time, is use the search feature of this board, and u will find all kinds of good stuff.




[This message has been edited by IROCZTWENTYGR8 (edited December 04, 2001).]

 

ttt

 

Though I've seen it repeated in several articles, I find it difficult to believe that lighter pistons contributed to an increase in HP. HP is merely a function of torque and RPM. 'Tis possible, but I'd like to see an engineering explanation.

Now, what I find more believable in the increased HP is the different cam used in the '90-'92 MAP setup:

<table border=1>
<tr><td>application</td><td>yellow</td><td>red</td><td>GM p/n</td><td>int lift</td><td>exh lift</td><td>int dur/td><td>exh dur</td><td>L/S</td><td>(in/exh)</td></tr>
<tr><td>1988, 1989 305 5spd / 350 AT</td><td>5000</td><td>5500</td><td>10066049*</td><td>.415</td><td>.430</td><td>207</td><td>213</td><td>117.0</td><td>(116/-118)</td></tr>
<tr><td>1990-1992 305 G92 5spd / 350 AT</td><td>5000</td><td>5500</td><td>10111773*</td><td>.413</td><td>.428</td><td>202</td><td>207</td><td>114.5</td><td>(116/-116)</td></tr>
</table>

Comments?

[This message has been edited by afgun (edited December 04, 2001).]

[This message has been edited by afgun (edited December 04, 2001).]

 

All i have to say is which one is better?? maf or speed density?? Reason being, why did chevy go back to maf after 92 ??

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1985 Iroc Modifications:
Ram air,K&N filters,Mas Screens off, fins taken off,52 MM Throttle body,
Corvette servo,B&M Transmission shift kit,
Flowmaster exhaust system
March Performance pulleys
Hypertech super coil.

Fords are Like Tampons, Every PU$$Y Has One!

 

They went back to MAF because of ever-increasing emissions requirements. The MAF is more accurately able to measure the amount of air entering the engine and thus the computer can deliver a more precise load of fuel and reduce emissions.