modifications to a speed density system

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Dec 19, 2003 | 11:35 AM

grandaddy's66

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From: Eastern, Iowa

modifications to a speed density system

I have an 89 F-150 ext cab 4wd with a 5.8L and E30D.
How much modification can one do before one starts having trouble with the speed density system and therefore needs to burn a chip?

K&N?
Headers?
True dual exhaust or cat back? (or neither?)
6-71 blower with dual Projections and nitrous (just kidding)
Trans mods?
Is there any way I can easily reprogram the computer now for a little more juju?
I'm in the process of building a nice, torquey, stroked 351 that will DEFINITELY require a new chip, but for now, I want to do all I can to pep this old boy up and will not be going to a '93 Lightning MAF setup. Thanks!

I put a copy of this thread over in the 86-97 forum to see if those fellers can lend a hand - I'm not sure how to place the same thread in 2 places

Last edited by grandaddy's66; Dec 19, 2003 at 11:43 AM.

Dec 24, 2003 | 01:23 AM

FTE Ken

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From: Enjoying the real world.

Long tube headers will cause problems and set off the check engine light.

Blowers.... needs custom programmed chip.

What type of trans mods?

Yes, the computer can be reprogrammed by adding a chip. It can't be flash programmed like modern EEC-V computers.

Dec 27, 2003 | 12:00 AM

grandaddy's66

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Don't want to be rude and not reply, Ken, just getting all kinds of traffic over on the 87-96 board. Thanks for weighing in, though. Some differ with you over there about the headers, however. I wouldn't mind having you take a look over yonder and weighing in with some more of your good advice.

Last edited by grandaddy's66; Dec 27, 2003 at 12:06 AM.

Dec 29, 2003 | 12:15 AM

FTE Ken

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From: Enjoying the real world.

Okay... I'll chime in over there.

Jan 2, 2004 | 01:51 AM

bigblu

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Speed density system can handle virtually all mods, including H-C-I. The key factor is the cam. as speed density requires manifold vacuum to run properly. You can run headers of any size (long or shortys).

SD cams should not exceed 218*DUR@.050 INT/224*DUR@.050.
The LSA must be at least 114, and no narrower. Otherwise idle problems and surging will occur, thus messing up the SD computer.

Visit some mustang sites (50tech.com), and you'll see many SD stangs have run vertually all mods, including blowers, nitrous, with excellent results. There's only a few places that will burn a chip for SD, most people will convert to mass air flow. It's a very cheap conversion, they get much more precise A/F ratio, and cam size is no longer a factor.

FYI-my husband dictated this to me (sitting next to me, explaining to me also). He worked with SD for 11 years on his stang before switching to a stroker motor with a much larger cam, thus requiring the maf upgrade. Which can be done for $300.

Here's my hubby's site for additional info. He explains about SD vs MAF on it. He's well known on many sites as an SD guru.
http://www.50tech.com/cobragt87/

Jan 2, 2004 | 02:40 PM

grandaddy's66

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From: Eastern, Iowa

bigblu,

Am I correct in hearing you say that I can do the referenced mods and not have to burn a custom chip for the EEC-IV computer? There has been much discussion on both sides of that position. I checked your website and like what I saw and read. Just wanting to make sure I am reading you right (which I hope I am).

Thanks for weighing in...j

Last edited by grandaddy's66; Jan 2, 2004 at 02:45 PM.