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SLP 20TL

Old 12-28-2018, 05:49 PM
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SLP 20TL

Hey Guys

Just wondering if anyone has some information on where I would be able to get a SLP 20TL catback exhaust for an 87 formula any information would be appreciated!!
Old 12-29-2018, 01:23 AM
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Re: SLP 20TL

1996 would be a good place to start looking.

Seriously though, you're looking for something that hasn't been sold new in over a decade. Look everywhere, look often, offer a large reward, you still might not find one.
Old 12-29-2018, 10:50 AM
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Re: SLP 20TL

hahha no kidding eh I wish I had a time machine!!

yea figured I have the long dark winter to try and dig something out of someones garage or basement before I settle with something else in the spring time
Old 12-29-2018, 11:33 AM
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Re: SLP 20TL

Hawks has 1 for 900 bucks.
Old 12-29-2018, 11:34 AM
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Re: SLP 20TL

I have a regret. My former '83 had an SLP 2OTL, which I procured after great effort and expense.The car sold to someone in Germany. I am certain the new buyer had never heard of nor had any appreciation for what an SLP 2OTL was. As my '83 sat in my garage for several weeks, waiting for shipping arrangements, I fleetingly considered replacing that 2OTL with another exhaust and saving it for a future project. That seemed a bit douchebaggy to me, so I left it alone.

I wouldn't be surprised if that 2OTL ended up in a German scrap heap, shortly thereafter.
Old 12-29-2018, 12:27 PM
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Re: SLP 20TL

Originally Posted by tealman92
Hawks has 1 for 900 bucks.
Old 12-29-2018, 04:58 PM
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Re: SLP 20TL

Originally Posted by Drew
I don't know if you meant to post this in this thread but I am glad you did and I got to see it.
I just love that review,my wife says I have a big a++ head too(the one that is on my neck that is) maybe the hood will work for me
Old 12-29-2018, 05:27 PM
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Re: SLP 20TL

Originally Posted by Drew
Old 12-29-2018, 05:58 PM
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Re: SLP 20TL

Its a single inlet dual outlet muffler, whats the big deal?
Old 12-29-2018, 07:50 PM
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Re: SLP 20TL

Originally Posted by Tibo
Its a single inlet dual outlet muffler, whats the big deal?
I think if I had it to do over, I'd just get a Magnaflow single in, dual out. Getting the tailpipes to look right is the trick, though.
Old 12-29-2018, 09:28 PM
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Re: SLP 20TL

Originally Posted by Tibo
Its a single inlet dual outlet muffler, whats the big deal?
I agree. They didn't really have a distinctive sound from what I can remember. I thought both pipes on one side of a rwd car looked goofy then and I still feel the same now. Dynomax sold (or still does?) a true dual exhaust kit with both pipes out the left and nobody goes nuts over that setup.

/Rant
Old 12-29-2018, 11:11 PM
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Re: SLP 20TL

Originally Posted by 86blackiroc
I agree. They didn't really have a distinctive sound from what I can remember. I thought both pipes on one side of a rwd car looked goofy then and I still feel the same now. Dynomax sold (or still does?) a true dual exhaust kit with both pipes out the left and nobody goes nuts over that setup.

/Rant
Well.....the whole thing about them, is that they sound awesome.
Old 12-30-2018, 08:02 PM
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Re: SLP 20TL

Spintech remakes the 4th gen Two on the left, it doesn't have the distinctive third gen tips. I bought one for my GTA, told them I needed the third gen dual cat intermediate pipe, 4th gen two on the left rear section, the exhaust shop had to modify a hanger, but it worked.
Old 12-30-2018, 08:14 PM
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Re: SLP 20TL

Originally Posted by chazman
Well.....the whole thing about them, is that they sound awesome.
I remembered them sounding similar to the Hooker catback exhaust. But it's been so long...
Old 12-30-2018, 09:00 PM
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Re: SLP 20TL

I have one. I dont think you are missing anything. Its not that loud to me. sounds just OK. The gale banks sounds better IMO
Old 12-30-2018, 09:56 PM
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Re: SLP 20TL

Originally Posted by punkmaster98
I have one. I dont think you are missing anything. Its not that loud to me. sounds just OK. The gale banks sounds better IMO

Do you want to sell it?
Old 12-30-2018, 10:27 PM
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Re: SLP 20TL

Hey what year car do you have your catback on? it definitely sounds better than stock so I'm interested lol
Old 12-31-2018, 02:52 PM
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Re: SLP 20TL

Originally Posted by chazman
Do you want to sell it?
not at the moment.
Old 12-31-2018, 03:59 PM
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Re: SLP 20TL

Originally Posted by punkmaster98
not at the moment.

No sweat. If you ever do, you know where to find me.
Old 12-31-2018, 06:55 PM
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Re: SLP 20TL

Blood in the water. GET HIM!
Old 01-01-2019, 03:04 AM
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Re: SLP 20TL






$375 - not mine - don’t know the seller. Seen others in LA recently. Happy hunting.
https://offerup.co/02HsSNJq7S
Old 01-01-2019, 05:21 AM
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Re: SLP 20TL

I installed one in my car in 1994.
Old 01-01-2019, 09:16 AM
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Re: SLP 20TL

1987 Camaro Iroc-Z28, original owner and I installed the SLP 2otl in 2002. Sounds great at idle and when you floor it, but it is not annoying at cruising speeds. Also the look is different from the stock set-ups.

Last edited by DJP87Z28; 01-01-2019 at 09:20 AM.
Old 01-01-2019, 09:33 AM
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Re: SLP 20TL

Originally Posted by DJP87Z28
1987 Camaro Iroc-Z28, original owner and I installed the SLP 2otl in 2002. Sounds great at idle and when you floor it, but it is not annoying at cruising speeds. Also the look is different from the stock set-ups.

Yup, loud enough, nice idle burble and no droning. I foolishly once had a Flowmaster. People outside thought it sounded good, but inside I was ready to blow my brains out after 20 minutes, due to it's incessant droning.
Old 01-01-2019, 09:35 AM
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Re: SLP 20TL

Originally Posted by acesena4





$375 - not mine - don’t know the seller. Seen others in LA recently. Happy hunting.
https://offerup.co/02HsSNJq7S
Looks like a nice one.
Old 01-01-2019, 09:46 AM
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Re: SLP 20TL

Originally Posted by Tibo
Its a single inlet dual outlet muffler, whats the big deal?
EXACTLY !!
I cant figure out why so many here go nuts over anything SLP.....
We all like different stuff but for me, the 2OTL looks stupid on a third gen. That look belongs on a British sports car
like a Triumph TR-6, not an american 80's muscle car and if you want it for sound only, lots of other choices out there
Old 01-01-2019, 11:54 PM
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Re: SLP 20TL

Keep watching and searching, I’ve had a few. I have a NOS complete setup from the headers to the tips that I picked up locally off Craigslist
Old 01-02-2019, 09:57 AM
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Re: SLP 20TL

Originally Posted by punkmaster98
I have one.
One? I thought you said you had 3 or 4? Or was that Eric?
Old 01-02-2019, 11:00 AM
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Re: SLP 20TL

Originally Posted by scooter
One? I thought you said you had 3 or 4? Or was that Eric?
Jon has 2 I only have 3 so far, one is nos

My bit of advice is check the exhaust on every junkyard car or every car being parted out add you come across. A lot of people may have one and not know what it is so it’s never listed properly. That’s how I ended up with one of mine
Old 01-02-2019, 11:47 AM
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Re: SLP 20TL

Oh you're hoarding them all, lol
Old 01-02-2019, 01:57 PM
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Re: SLP 20TL

I have 6+ SLP TOTL catback exhausts plus extra tails and mufflers. 3 are on cars now. One of the catbacks is from 87-90 and its the oval tip steel turbo muffler. (not near as good as the later stainless setups)
Old 01-02-2019, 06:17 PM
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Re: SLP 20TL

I appreciate the insight guys


hoping for some Canadian friends who may have something available aswell
Old 01-02-2019, 08:47 PM
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Re: SLP 20TL

Originally Posted by BizJetTech
EXACTLY !!
I cant figure out why so many here go nuts over anything SLP.....
We all like different stuff but for me, the 2OTL looks stupid on a third gen. That look belongs on a British sports car
like a Triumph TR-6, not an american 80's muscle car and if you want it for sound only, lots of other choices out there
I had a 2otl on both my formula and firebird and thought it looked better with the gfx imo
Old 01-03-2019, 05:25 PM
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Re: SLP 20TL

Great stuff guys!
Everybody has their own feel on what looks and sounds the best.
Obviously I'm in search of the one I feel to be the best in both categories
Old 01-08-2019, 10:26 PM
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Re: SLP 20TL

I have the SLP TOTL and their 1 3/4 headers on my 91 Z28 and I love the way it sounds. My friend has a G8 with Kooks headers, Borla cat-back, heads and cam. He told me when he is driving behind me, my car drowns his car out, he could barely hear his car.
Old 01-10-2019, 08:59 AM
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Re: SLP 20TL

Originally Posted by 91chevyz28
I have the SLP TOTL and their 1 3/4 headers on my 91 Z28 and I love the way it sounds. My friend has a G8 with Kooks headers, Borla cat-back, heads and cam. He told me when he is driving behind me, my car drowns his car out, he could barely hear his car.
is your friend running catalytic converters?
Old 01-10-2019, 02:17 PM
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Re: SLP 20TL

Originally Posted by 91chevyz28
I have the SLP TOTL and their 1 3/4 headers on my 91 Z28 and I love the way it sounds. My friend has a G8 with Kooks headers, Borla cat-back, heads and cam. He told me when he is driving behind me, my car drowns his car out, he could barely hear his car.

Jealous man no way you would wanna part ways with the cat back and just go straight pipe eh? lool
Old 01-10-2019, 10:59 PM
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Re: SLP 20TL

Originally Posted by Tibo
is your friend running catalytic converters?
Yes, high flow.
Old 01-11-2019, 07:49 AM
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Re: SLP 20TL

Forgot to mention I do not have a catalytic converter on my car but I still have the smog pump hooked up.
Old 01-12-2019, 04:32 PM
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Re: SLP 20TL

Originally Posted by Tibo
Its a single inlet dual outlet muffler, whats the big deal?
Originally Posted by 86blackiroc
I agree. They didn't really have a distinctive sound from what I can remember.
They were a good flowing muffler that many felt was a very good compromise between loud and quiet when you wanted it.

I thought both pipes on one side of a rwd car looked goofy then and I still feel the same now. Dynomax sold (or still does?) a true dual exhaust kit with both pipes out the left and nobody goes nuts over that setup.

/Rant
there's nothing on these cars that signals "I need a dual exhaust...," like my 4th gen TA had cutouts in the back bumper for a tailpipe on each side, and looked weird when emtpy. Nothing like that on 3rd gens. I kept trying to put a tailpipe on each side on these things for years till I figured out that they really look better with them either hidden/tucked like stock (and then at that point what does it matter if it's a single or dual if you can't see it, whatever fits best, flows best and sounds like you want it, and as far as fit and sound, out the driver's side works best for these cars) or something tasteful that just tucks down like the TTL did.

Dynomax never sold a true dual kit. Their original kit had a single 3" slash cut out the driver's side, that was replaced by dual tips out the driver's side (various configurations, but the most common actually had square tips), and then they sold parts for the stock configuration with tucked tips on both sides out of a single crossflow muffler (I'm not sure that they ever sold that as a kit)
Old 01-12-2019, 04:43 PM
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Re: SLP 20TL

Honestly, I've never understood the crazy prices that people charge and are willing to pay for SLP stuff. I've ended up with a bunch of it that came with one of the 3rd gens that I bought and sold some of it off always letting the buyer offer and always coming to a price that was WAY more than I thought my junk was worth and the buyer was always happy getting it cheaper than they thought it was worth... Oh well.

I've cut up a few of these TTL exhausts, I'm pretty sure I might still have at least one set of tips and muffler in my scrap pile. They sounded nice, flowed well and looked good, but weren't all that well made. Mostly 4xx series stainless (which gets a brownish rust coat on it, it doesn't stay bright like a 3xx stainless), and they tended to rust out/break where the hangers and other bits were welded. I've seen a bunch, including 2 that were on cars that I bought, that had the intermediate pipe break right after the axle at the hanger there. I think that the intermediate pipe on my car might be one that I cut off and welded to a section of a Magnaflow pipe, I'd bet that if I looked hard enough I could find a patched SLP pipe in my garage somewhere also. Mind you, I don't live in the rust belt (DC Metro area) which gets treated roads less maybe half a dozen times a year and the 2 cars that I bought with these exhausts on them supposedly weren't driven in the winter at all (both were parked stored with loads of spare and original parts by meticulous owners, so I'm tempted to believe that).

Besides being SLP items they're nothing that you couldn't build better on your own
Old 01-12-2019, 05:07 PM
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Re: SLP 20TL

Originally Posted by 83 Crossfire TA
Dynomax never sold a true dual kit.
Except that they did, and do.

https://www.summitracing.com/parts/w...maro/year/1987



It's never been very popular or advertised well since it's not street legal, emissions legal, and likely flows worse than the stock exhaust, but it's been available for decades.
Old 01-14-2019, 11:35 PM
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Re: SLP 20TL

Originally Posted by Drew
Except that they did, and do.

https://www.summitracing.com/parts/w...maro/year/1987



It's never been very popular or advertised well since it's not street legal, emissions legal, and likely flows worse than the stock exhaust, but it's been available for decades.
Well, I stand corrected... Looks like this thing turned up sometime between 2009 and 2013 (there are references to it before then but no references to anyone having it, and i seem to remember a period around then that Dynomax listed a lot of parts that didn't exist IRL), and I'm not sure that it really counts as a kit since it appears to be just pipes, no mufflers, brackets... Funny, most sites seem to list it as a universal kit but it's clearly for f-bodies.

I can't seem to find any pics of one installed, I'm curious what the layout was for the mufflers- if there was room for 2 or if you had to run a dual in/dual out. If anyone knows of any please post or link.

"flows worse than stock..." I'd bet that depends on the mufflers used and what stock exhaust, but most likely. The early performance exhaust (with the dual rear mufflers) sounded as good or better than a lot of aftermarket (never seen any performance testing) and the stock performance exhaust by the late 80's early 90's (and later on the 4th gens) flowed as well as most aftermarket exhaust- I tested the stock exhaust vs magnaflow and open pipes on my 4h gen and wasn't able to document any performance difference on a heavy mid 11second car. People don't realize how little power difference there is with any of the common exhaust setups... My current setup on my '87 is a 3" intermediate pipe (I think the front half is SLP, back half Magnaflow, but I'd have to look for sure) with a cutout in it, and rear section with a flange so i can swap muffler/tailpipe as my mood changes, and I've had stock 4th gen, SLP TTL, dynomax ultraflow welded 3" in and out and 2 different homemade setups and I can't document any performance difference between any of them, cutout open or closed.
Old 01-15-2019, 07:47 AM
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Re: SLP 20TL

Originally Posted by Eric-86sc


Jon has 2 I only have 3 so far, one is nos

My bit of advice is check the exhaust on every junkyard car or every car being parted out add you come across. A lot of people may have one and not know what it is so it’s never listed properly. That’s how I ended up with one of mine
figures you would have that lol
Old 01-15-2019, 03:04 PM
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Re: SLP 20TL

Originally Posted by 83 Crossfire TA
Well, I stand corrected... Looks like this thing turned up sometime between 2009 and 2013
The PDF instructions are dated 1999. Pretty sure it dates back a lot further, 1999 was just when they PDF'd the instructions. I've seen one on a junkyard car in the late 90s/early 2000s, it'd been on there a good long time because it was rusty as hell. It's a convoluted mess of an exhaust, but meatheads are crazy about them "TRUE DUELS". The crush bent pipes and the sheer complexity of trying to tuck a pair of pipes in place of a single 2.75" pipe, pretty much dictates that it's a waste of time.

According to the instructions, they expect you to use two small turbo mufflers. The one I saw had "Muh Cherry Bombs"... I don't think anyone in the know would look at this kit and think Wow! but there are several reviews on Summit, so someone must be buying them.


Old 01-15-2019, 03:15 PM
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Re: SLP 20TL

Funny... Pulled up the headers they say to use with the dual exhaust, Dynomax 85012.



That's the actual photo on Summit's website. LOL Unfortunately they're discontinued, but never fear! These Dynomax headers are the garbage presently known as "Flowtech" headers. Frequently regarded as one of the worst headers on the market that will fit a thirdgen.

This stuff really falls under the category of parts that have been around forever, but are universally discredited as being poor choices for one reason or another. I remember this stuff in the Summit and JCWhitney catalogs of the 90s, dirt cheap ($75 headers, $120 exhaust) compared to everything else. But everyone knew they weren't worth messing with. But that was before the Rustoleum paint jobs, 4th gen seats, and Lambo doors...
Old 01-15-2019, 05:03 PM
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Re: SLP 20TL

If you look at one of SLPs very early test cars, it has true dual exhaust through one muffler and a TOTL exit.

https://thirdgenfbody.files.wordpres...04/hr-pg58.jpg

Last edited by TTOP350; 01-18-2019 at 04:29 PM.
Old 01-16-2019, 09:52 PM
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Re: SLP 20TL

Originally Posted by Drew
The PDF instructions are dated 1999. Pretty sure it dates back a lot further, 1999 was just when they PDF'd the instructions. I've seen one on a junkyard car in the late 90s/early 2000s, it'd been on there a good long time because it was rusty as hell. It's a convoluted mess of an exhaust, but meatheads are crazy about them "TRUE DUELS". The crush bent pipes and the sheer complexity of trying to tuck a pair of pipes in place of a single 2.75" pipe, pretty much dictates that it's a waste of time.

According to the instructions, they expect you to use two small turbo mufflers. The one I saw had "Muh Cherry Bombs"... I don't think anyone in the know would look at this kit and think Wow! but there are several reviews on Summit, so someone must be buying them.


A co-worker installed that dual exhaust setup on his '83 T/A back around '96 or so. As you would expect, it fit poorly. It was 2.25 tubing from what I remember. It used a pair of short turbo mufflers.

In '02 or so, I removed that system and Installed a Dynomax cat-back meant for an '86-up TPI car. It had a crossflow muffler and a factory type tailpipe on both sides of the car. No crush bends either. After a year or so, that system got poop-canned as well in favor of Edelbrock headers and a Flowmaster cat-back. Ya'll can judge, but I was the one that picked that setup and the owner was finally happy with the sound and fitment.

Its funny you mention that the old Dynomax headers are now Flowtech headers. I have no recent experience with them in third gens, but Flowtech headers fit great in squarebody trucks and they are far better than the old Dynomax headers.

Last edited by 86blackiroc; 01-16-2019 at 09:57 PM.
Old 01-17-2019, 09:55 PM
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Re: SLP 20TL

As I mentioned before I have the TOTL on my 91 Z28. I have an opportunity to purchase a Borla exhaust with the 2 quad tips and adjustable plates for the passenger side exit. I need some opinions if I should change my exhaust to the Borla or stick with the period correct TOTL. If you have an opinion, please let me know, thanks.
Old 01-18-2019, 02:35 PM
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Re: SLP 20TL

Originally Posted by 91chevyz28
As I mentioned before I have the TOTL on my 91 Z28. I have an opportunity to purchase a Borla exhaust with the 2 quad tips and adjustable plates for the passenger side exit. I need some opinions if I should change my exhaust to the Borla or stick with the period correct TOTL. If you have an opinion, please let me know, thanks.
I think you should give the borla a shot!
I would definitely be interested in picking the TOTL catback from you if you decide to switch it up!

keep me posted please!

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