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Same cam and intake-new heads. Same tune???

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Old 03-18-2010, 07:06 PM
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Car: 1988 Iroc
Engine: L98 350
Transmission: 700R4
Axle/Gears: Hawks 8.8 - 3.73
Same cam and intake-new heads. Same tune???

Right now motor is basically a stock L98 with a ZZ4 cam. Couple bolt ons. LOVE the way the car runs. The basic question is if I get a better set of heads, say some 180cc trick flows, can I run the same tune? Now before you answer, I KNOW I'll be giving away power. I'm looking for how it'll run.

Here's my thinking. I'm actually thinking about getting a whole new shortblock, but similar (just stronger) than the L98. I plan to keep the ZZ4 cam, but no way I'm keeping the stock heads. I'm also planning to go with the EFI connection 24x set up. I'd like to get the new motor up and running on the traditional ignition/engine management, work out the bugs, and THEN do the 24x swap. I'd hate to deal with tuning just to (hopefully) turn right around and yank out the computer, tune, etc. etc. when I do the 24x. Like I said, I understand I'll be leaving power on the table, as the heads will have SO much more potential, but I'm curious how it'll run. You always hear about cam swaps with the same heads, but not often you hear head swaps with the same cam!

Thanks for the 2 cents!
Old 03-19-2010, 12:04 AM
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Re: Same cam and intake-new heads. Same tune???

Being that its a MAF type TPI system I'm assuming I figure it will probably run fairly well. Like you said not to say it wouldn't like a tune it probably wont perform to its potential it may not run perfect in terms of drive ability but my guess is it will surprise you with how well it runs considering its on a stock tune.
Old 03-19-2010, 12:39 AM
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Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: Same cam and intake-new heads. Same tune???

Originally Posted by Rolling Thunder
Being that its a MAF type TPI system I'm assuming I figure it will probably run fairly well. Like you said not to say it wouldn't like a tune it probably wont perform to its potential it may not run perfect in terms of drive ability but my guess is it will surprise you with how well it runs considering its on a stock tune.
From my readings of various posts, I would also have to agree... MAF system will be able to adjust its parameters to a custom build, unlike Speed, which requires a custom tune...
Old 03-19-2010, 09:37 PM
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Re: Same cam and intake-new heads. Same tune???

The VE will change at WOT and the burn speed in the chamber will likely slow some. Basically a little adjustment to the PE and SA tables should cover most of what is needed.
If your tune is good now, then you'll probably be happy with how it runs with the new heads, even with a slightly lazy tune.
Old 03-19-2010, 09:56 PM
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Re: Same cam and intake-new heads. Same tune???

It may run fine but it obviously it wont be as good as it could be. A head change drastically effects the burn and the increased flow will lean you out more than likely. MAF can only compensate so much before it runs out of ability. If it does lean out some try adjusting fuel pressure to get you by. May work.

But with ZZ4 cam i dont expect the car to run that poorly with new heads. It should run pretty good for now. Although the heads would flow a ton more than stock the cam isnt huge so the MAF tables should only need minor adjustment
Old 03-19-2010, 10:41 PM
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Car: 1988 Iroc
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Re: Same cam and intake-new heads. Same tune???

Thanks for the replies. I know a lot of you know more than I do, but from my reading, I think we kinda agree it'll be ok.

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