LT headers worth it on an L98
Team Owner
Joined: Jul 2004
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From: Hartford WI
I like the idea of improving the intake too...whether just the tubes or a superram. Without a cam change, these two mods might run fine w/o a tune -- though it never hurts to get TunerPro to see what's going on. TunerPro is a good tool for general diagnosis as well...and is cheap.
Race Director
Joined: Nov 2003
Posts: 12,221
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I think it's because the MAF setup prior to 90 was more forgiving.
FP increase might help too...as many have noted in other threads. Personally, I've always been a bit surprised when people say more FP helps (stock cars). From what I've seen in the stock tune(s) posted online (and as I used as a starting point for my mods), it's already pretty rich. Though, not so rich as to fall outside correctable range. Maybe that's what people like as a result....better tip-in? As WOT, more fuel might also provide better torque at the expense of HP....but who's looking for HP on an L98?!?!
FP increase might help too...as many have noted in other threads. Personally, I've always been a bit surprised when people say more FP helps (stock cars). From what I've seen in the stock tune(s) posted online (and as I used as a starting point for my mods), it's already pretty rich. Though, not so rich as to fall outside correctable range. Maybe that's what people like as a result....better tip-in? As WOT, more fuel might also provide better torque at the expense of HP....but who's looking for HP on an L98?!?!
Melting Slicks
Joined: Aug 2003
Posts: 3,407
Likes: 400
From: Lakeville MI
If doing this again, I would be very tempted to start with something like this (with the manifold down pipes) or equivalent:
http://pypesexhaust.com/i-12200821-8...em-scc40r.html
http://pypesexhaust.com/i-12200746-8...pes-dcc40.html
Gotta admit that I don't like the tips, but it does sound good in the video.
Note: I gained nothing by adding lpe 1 5/8" long tubes and an x-pipe to a pre-existing 2 1/4" true dual system without cats. Car was already in the mid-13s at this point in time with and without long tubes.
I think replacing the rest of the exhaust first is the way to go on an L98. Can always easily add long tubes later if you really want them.
http://pypesexhaust.com/i-12200821-8...em-scc40r.html
http://pypesexhaust.com/i-12200746-8...pes-dcc40.html
Gotta admit that I don't like the tips, but it does sound good in the video.
Note: I gained nothing by adding lpe 1 5/8" long tubes and an x-pipe to a pre-existing 2 1/4" true dual system without cats. Car was already in the mid-13s at this point in time with and without long tubes.
I think replacing the rest of the exhaust first is the way to go on an L98. Can always easily add long tubes later if you really want them.
Last edited by tequilaboy; Mar 13, 2018 at 05:26 PM.
Team Owner
Joined: Jul 2004
Posts: 28,495
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From: Hartford WI
Did the EGR hook up too? I suppose if not you can blank out the EGR code and remove the problem part? Assuming you do not have the smog **** state bothering you.
Melting Slicks
Joined: Feb 2015
Posts: 2,069
Likes: 262
From: Park Ridge New Jersey
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
For appearance sake, shorties would look better than LTx manifolds...specifically because of the EGR fittings. Sometimes they cost nearly as much as longtubes though. There's been a set of shorties in C4 parts for months and months but the price is too close to long tubes. Mid 2017, I remember someone ported a stock set of L98 manifolds then had them coated. They were priced right. I assume they were sold.
I like the look of those OBX headers for a stock motor w/o much else being modded. Obviously mixed feedback -- but so were the "custom" headers I bought back in 2007. Once all was said/done, I considered the feedback (including my own) a bit too whiney. They weren't "bolt-on" like TPIS but I enjoyed the bracketology. Really surprising considering my install wasn't during March Madness!
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Melting Slicks
Joined: Feb 2015
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From: Park Ridge New Jersey
Team Owner
Joined: Jul 2004
Posts: 28,495
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From: Hartford WI
Racer
Joined: Jul 2000
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From: Chandler,AZ,USA AZ
You're getting a lot of comments but...
You might want to get a copy of John Lingenfelters book on modifying the small block Chevy. He makes an interesting comment about the tubes that came on the L98s Vs long tubes.