Stock vehicles - aftermarket downpipe increase floor/cabin temps?
02-21-17, 02:22 PM
#1
Stock vehicles - aftermarket downpipe increase floor/cabin temps?
Anyone with a stock FD (or can remember their FD in stock form) know if removing the stock downpipe, which has the precat (itself a source of heat), is a main cause of the "hot transmission tunnel" ? The reasoning would be that the stock heat shields prevent the cabin from getting too hot, whereas an unwrapped aftermarket downpipe heats up the floor boards.
I don't know if ever been in an FD that didn't get noticeably hot in that area but I don't remember the last time I rode in a truly stock one with all heat shields intact either.
I'm asking because I'm thinking about buying a stock FD and I would want to keep it a "normal" car. And to me there's no way a $40k car in 1993 got hot like that when brand new.
I don't know if ever been in an FD that didn't get noticeably hot in that area but I don't remember the last time I rode in a truly stock one with all heat shields intact either.
I'm asking because I'm thinking about buying a stock FD and I would want to keep it a "normal" car. And to me there's no way a $40k car in 1993 got hot like that when brand new.
02-21-17, 02:40 PM
#2
These cars actually got pretty hot stock. So much in fact that Mazda installed a temperature sensor in the passenger floorboard and the overheat exhaust system light. That being said, I've never seen one actually go off. Excessive heat in the floorboard is usually attributed to a clogged cat, or missing heat shields on the exhaust and turbo system. Heat wrapping the downpipe and exhaust piping with DEI titanium and installing some heat shielding under the carpet makes a big difference.
02-21-17, 03:09 PM
#3
Totally stock (pre-cat + all heat shields, carpet, and insul) = not hot
Substituting a wrapped DP for the pre-cat and high flow cat for stock cat while retaining all heat shields, carpet and insul = not hot.
Have no data points for any other alternative
Substituting a wrapped DP for the pre-cat and high flow cat for stock cat while retaining all heat shields, carpet and insul = not hot.
Have no data points for any other alternative
02-21-17, 03:54 PM
#4
Racecar - Formula 2000
I have the HKS DP with Jet-Hot 2000 inside and out. No heat issues apparent with that setup.
02-21-17, 10:30 PM
#7
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02-22-17, 09:32 AM
#9
I have a JDM DP gathering dust. pay shipping and you can have it
when I removed the precat and replaced with a jethot coated and dei wrapped DP I had no more heat than stock.
when I went with a larger DP uncoated and unwrapped the trans tunnel and pass floor get noticeable hotter
when I removed the precat and replaced with a jethot coated and dei wrapped DP I had no more heat than stock.
when I went with a larger DP uncoated and unwrapped the trans tunnel and pass floor get noticeable hotter
02-22-17, 09:39 AM
#10
RX-7 Bad Ass
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I would second the Jet-Hot recommendation.
https://www.jet-hot.com/
Their 2000 degree coating is amazing. Big time reduces underhood temps and keeps the heat where it needs to be. The stuff is VERY durable as well, I've done a number of downpipes with it with absolutely no discoloration, flaking, anything.
Matter of fact a buddy totalled his FD and the downpipe took a hard hit in the wreck and dented it. The Jet-Hot didn't come off at all, didn't flake or crack.
Last I remember it was like $120 to have it done. If you want a second bung for a wideband, I would get that welded on first and then just plug the hole up.
Dale
https://www.jet-hot.com/
Their 2000 degree coating is amazing. Big time reduces underhood temps and keeps the heat where it needs to be. The stuff is VERY durable as well, I've done a number of downpipes with it with absolutely no discoloration, flaking, anything.
Matter of fact a buddy totalled his FD and the downpipe took a hard hit in the wreck and dented it. The Jet-Hot didn't come off at all, didn't flake or crack.
Last I remember it was like $120 to have it done. If you want a second bung for a wideband, I would get that welded on first and then just plug the hole up.
Dale
02-22-17, 11:56 AM
#11
Always Bad Advice
Here is another data point. I have a gutted precat. I cut it apart, removed all the innards, ground all the welds smooth on the inside, welded it back together, and reattached all the OEM heat shields. There was no discernible difference in the amount of heat coming up.
02-22-17, 02:57 PM
#12
02-22-17, 07:01 PM
#15
I'm wondering what difference the stock DP made in underhood temps though.
And arghx, don't sell the DEI wrap short. I stayed with it when the coating wasn't available in my area at the time. It's low tech old-school, and not as cool looking, but it's a quarter of the cost and with the twins not much shows. And with their 'ceramic sealant' it works well. I can pull of the highway and it less than 5 minutes have it up on the lift and grab the DP with my hands. No heat issue to the floors and the sealant keeps it from being itchy to work around. Plenty left to do the inlet and outlet of the main cat too.
And arghx, don't sell the DEI wrap short. I stayed with it when the coating wasn't available in my area at the time. It's low tech old-school, and not as cool looking, but it's a quarter of the cost and with the twins not much shows. And with their 'ceramic sealant' it works well. I can pull of the highway and it less than 5 minutes have it up on the lift and grab the DP with my hands. No heat issue to the floors and the sealant keeps it from being itchy to work around. Plenty left to do the inlet and outlet of the main cat too.
Last edited by Sgtblue; 02-22-17 at 07:14 PM.
02-22-17, 08:57 PM
#16
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I'm wondering what difference the stock DP made in underhood temps though.
And arghx, don't sell the DEI wrap short. I stayed with it when the coating wasn't available in my area at the time. It's low tech old-school, and not as cool looking, but it's a quarter of the cost and with the twins not much shows. And with their 'ceramic sealant' it works well. I can pull of the highway and it less than 5 minutes have it up on the lift and grab the DP with my hands. No heat issue to the floors and the sealant keeps it from being itchy to work around. Plenty left to do the inlet and outlet of the main cat too.
And arghx, don't sell the DEI wrap short. I stayed with it when the coating wasn't available in my area at the time. It's low tech old-school, and not as cool looking, but it's a quarter of the cost and with the twins not much shows. And with their 'ceramic sealant' it works well. I can pull of the highway and it less than 5 minutes have it up on the lift and grab the DP with my hands. No heat issue to the floors and the sealant keeps it from being itchy to work around. Plenty left to do the inlet and outlet of the main cat too.
Last edited by j9fd3s; 02-22-17 at 09:03 PM.
02-22-17, 09:01 PM
#17
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my friend had one without the heat shield on it, the pipe is TEENY, it looks like a wet cat...
02-23-17, 07:00 AM
#18
Racecar - Formula 2000
Jet-Hot Link
https://www.google.com/url?sa=t&rct=...48073327,d.eWE
Last edited by DaveW; 02-23-17 at 07:05 AM.
02-23-17, 08:12 AM
#19
I can remember the exact video, but a was researching inconel and I came across a video where the person said that the exhaust(down pipe) of rx7 were made with inconel aloy because of the rotary engine's exhaust high heat.
I though , it was really cool if it's true.
I though , it was really cool if it's true.
02-23-17, 06:33 PM
#20
I remember when I switched from the stock pre cat to a downpipe I noticed the engine bay was a bit cooler, granted I only noticed the difference after an hour or so of driving no immediate difference. I have a midpipe laying around that i will put in place, ill try and remember to let you guys know if i notice a temperature difference in the cabin.
07-01-17, 11:46 PM
#21
Senior Member
Still got it?
I have a JDM DP gathering dust. pay shipping and you can have it
when I removed the precat and replaced with a jethot coated and dei wrapped DP I had no more heat than stock.
when I went with a larger DP uncoated and unwrapped the trans tunnel and pass floor get noticeable hotter
when I removed the precat and replaced with a jethot coated and dei wrapped DP I had no more heat than stock.
when I went with a larger DP uncoated and unwrapped the trans tunnel and pass floor get noticeable hotter
Replaced the engine and a lot of brittle hoses and wire problems; would like to reduce the heat on the new engine.
Your JDM DP: Fits stock dual turbos, and has air port?
07-02-17, 02:10 PM
#22
I'm super happy with my JDM downpipe. It has No cabin heat problems, looks like stock, no noise, fits a stock turbos US car, probably a slightly less restriction. I have stock main cat. There is no impact on the secondary air injection pipe.
yesterday I drove around in stop and go with the A.C. and did not feel the cabin get hot in the downpipe area.
yesterday I drove around in stop and go with the A.C. and did not feel the cabin get hot in the downpipe area.
Last edited by arghx; 07-02-17 at 02:13 PM.
07-07-17, 12:31 PM
#23
Senior Member
I have an HKS DP that I bought brand-new earlier this year and sent out to SwainTech for their "White Lightning" exhaust coating. I haven't installed it yet because I'm being a colossal ***** about getting underneath my car on jack stands. 
For some reason I'm feeling my mortality lately. Thinking of getting a QuickJack prior to doing the work.
Anyhow, the coating cost about $85 I think, but then shipping out and back took it up to $140. The HKS downpipe was like $220, new.
For some reason I'm feeling my mortality lately. Thinking of getting a QuickJack prior to doing the work.Anyhow, the coating cost about $85 I think, but then shipping out and back took it up to $140. The HKS downpipe was like $220, new.