speed density?
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,049
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From: Texas
speed density?
OK, what is the difference if any performance wise of this and a MAF? And besides performance, how does it affect the car differently?
And what years had the system? :confused:
Did any of the LT1s have this? If so, is there anything you should do to improve the performance of it, or is it OK like it is?
And what years had the system? :confused:
Did any of the LT1s have this? If so, is there anything you should do to improve the performance of it, or is it OK like it is?
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Re: speed density? (BowTieBlood)
Well I know the 92-93 LT1 have it, but I have no idea what the hell it is.
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Re: speed density? (BowTieBlood)
I don't know which year switched from MAF to speed density, but they both do the same thing, and that is provide the ECM what mass of air is entering the intake so it can decide what pulse length the fuel injectors must have in order to maintain the proper air to fuel ratio for the throttle setting and engine load.
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: speed density? (BowTieBlood)
In the early L98s ('95-89) air flow into the engine is measured directly by the MAF; in the '90 & 91 L98s it is computed from MAP sensor and other sensor values. The later LT1s used a different MAF, but not sure if the early LT1s used MAF or SD.
The MAF based L98 is easier to modify as it doesn't require an EPROM change till more extensive mods have been done, if at all; whereas a SD based L98 usually requires EPROM changes to match fuel properly to computed air flow. Also it is much more difficult to get the EPROM mapping correct with a SD system.
The SD system is sensitive to mods that change manifold pressure (like cam change) while the MAF is not.
The MAF based L98 is easier to modify as it doesn't require an EPROM change till more extensive mods have been done, if at all; whereas a SD based L98 usually requires EPROM changes to match fuel properly to computed air flow. Also it is much more difficult to get the EPROM mapping correct with a SD system.
The SD system is sensitive to mods that change manifold pressure (like cam change) while the MAF is not.
Safety Car
Joined: May 1999
Posts: 3,588
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From: Volcano, HI
Re: speed density? (65Z01)
The MAF based L98 is easier to modify as it doesn't require an EPROM change till more extensive mods have been done, if at all; whereas a SD based L98 usually requires EPROM changes to match fuel properly to computed air flow. Also it is much more difficult to get the EPROM mapping correct with a SD system.
TNT-
How's the Haltec? How much was it and what did it come with??
[Modified by Mojo, 1:13 PM 1/4/2002]
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Safety Car
Joined: Jun 1999
Posts: 3,641
Likes: 2
From: Southern California
Re: speed density? (Mojo)
I know that my friend with a '94 is jealous as hell that my intake is less restrictive than his. If he says something about my car I just say "according hose" and he shuts up:lol:. Then I rub it in that my car is more free flow than his.
I did a post way back on this. Somebody gave some real detailed information on the differences. I'll try to fnd it for you.
I did a post way back on this. Somebody gave some real detailed information on the differences. I'll try to fnd it for you.
Safety Car
Joined: Jun 1999
Posts: 3,641
Likes: 2
From: Southern California
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,049
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From: Texas
Re: speed density? (Raysur)
Thanks that was very imformative :cheers:
Also, do you know which years had what? Is it '92-'93 of the LT1s that had the speed density? And then '94 up they switched back to MAF?
Also, do you know which years had what? Is it '92-'93 of the LT1s that had the speed density? And then '94 up they switched back to MAF?
Safety Car
Joined: Jun 1999
Posts: 3,641
Likes: 2
From: Southern California
Re: speed density? (BowTieBlood)
Is it '92-'93 of the LT1s that had the speed density? And then '94 up they switched back to MAF?