3800 Muffler- heat shield question (Page 1/1)
cam-a-lot SEP 08, 07:44 AM
Hello

I am getting my 3800 exhaust re-done soon and will be putting a muffler in the stock Fiero location. Currently my car has no muffler exhaust shield in the stock location, and I am struggling to find one.

1) are all fiero muffler heat shields the same, regardless of year or engine? My car is an 88 V6

2.) Do you guys normally put extra material under the heat shield for additional shielding to reduce heat getting into the trunk area?

3.) Any photos available and suggested material I can use for this ?

thanks
fieroguru SEP 08, 10:14 AM
1. Yes, the rear shield is the same across all years and models.

2. I don't. The air gap between the shield and truck allows air flow to keep the heat from entering the trunk area. Filling that area with something will allow it to collect moisture and possibly rust.

3. If your exhaust/muffler is stainless, you can use standard header wrap on it to help keep more of the heat in the mufflers and pipes. Be careful using insulating materials and only use materials rated for exhaust and engine bays. At least one 3800 swap burnt down due to improper insulation materials coming loose and setting on the exhaust. If it is going to be close to the exhaust, it needs to be rated to touch the exhaust.
cam-a-lot SEP 08, 08:04 PM
Great info, thanks Guru
Dennis LaGrua SEP 10, 05:43 AM
Both my swaps have a Spintech 13" muffler in the stock location. Even with the heat shield in place, the short exhaust causes much heat in the trunk area. The exhaust pipes were covered in exhaust wrap and that helped quiet things down a bit but not the heat. Using the U bend to muffler approach (to keep the full trunk) I don't see a solution.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 09-10-2024).]

Frenchrafe SEP 10, 07:17 AM
Yes, you will need some sort of heat shield.
I used the factory one with extensions riveted on to one side.
These extensions are made from 0.5mm galvanised sheet steel. It holds up well to the heat, and you could possibly make all the shield from this galva sheet, if you needed.
You must use steel rivets for the heat as well.

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM

longjonsilver SEP 10, 09:07 AM
i kept my trunk intact and the heat shield in the stock position. i wrapped the exhaust in heat shield tape rated for direct contact. i was still getting too much heat into the trunk - so much so that i melted some clothes in there. So i bot some heat shield cloth from amazon and that GREATLY helped. Replacing the carpet in the trunk has now made it quite cool in there - so we even put groceries there.

https://www.amazon.ca/dp/B0...dt_b_product_details

Its enuf for two trunks - my buddy did his also.

------------------
Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 3800SC, 4-wheel drifts are fun!

cam-a-lot SEP 13, 06:11 AM
Thanks LongJon

So you put this matting INSIDE the trunk, correct? Did you then put the factory carpet back over it?

Dennis, thanks for the info. I am running WCF headers and am routing the stock Fiero direction, so hopefully the longer exhaust dissipates "some" of the heat compared to using 3800 manifolds or P Logs.