Possible 3800 exhaust solution? (Page 1/1)
Johns 4.9 NOV 12, 06:18 PM
Hi. Any of you guys and gals interested in a dual exhaust system with headers for your 3800 series II swap? Still in the early stages of conception. Primary header tubes are 1 5/8 inches and the collectors are 2 1/4 inches. Mufflers are 18" long by 2 1/4 inches. This design will clear automatics and manual transmission equipped cars and has additional clearance for accessories on the front side of your engine.
Comments? Ideas? Recommendations? Good and bad? I welcome your responses. Trying to come up with an exhaust solution for my 3800 Fiero friends. Thank you.
Cheers
Rickady88GT NOV 12, 09:17 PM

quote
Originally posted by Johns 4.9:

Hi. Any of you guys and gals interested in a dual exhaust system with headers for your 3800 series II swap? Still in the early stages of conception. Primary header tubes are 1 5/8 inches and the collectors are 2 1/4 inches. Mufflers are 18" long by 2 1/4 inches. This design will clear automatics and manual transmission equipped cars and has additional clearance for accessories on the front side of your engine.
Comments? Ideas? Recommendations? Good and bad? I welcome your responses. Trying to come up with an exhaust solution for my 3800 Fiero friends. Thank you.
Cheers






That is a super cool program. Thanks for the helpful advice and input. Very cool idea and excellent execution of said suggestion.
My hat's off to you.
I do not have a V6 but I can see how this suggestion can help the v8 snappers as well.
Raydar NOV 12, 09:24 PM
John... You're knocking this stuff out of the park! Good show!

[This message has been edited by Raydar (edited 11-15-2020).]

DimeMachine NOV 12, 10:33 PM
Love it but have one concern.

Stock 3800 GM PCM management has only one O2 sensor. If you use one sensor in one bank you are getting only 3 cylinders data which could skew things quite a bit if something is going on with any one cylinder.

Thoughts on this?

Dime

------------------
84/87 NB, 3800SC, E-85, VS Cam, 2.8 Pulley, 4T65E-HD, HP Tuners, AEM Wideband, Regal GS Gauges, S-10 Brake Booster. 1/4 mile -11.85 at 114mph

Johns 4.9 NOV 12, 11:29 PM
Hi Dime,
Good point. Some of the guys I was talking with wanted to run dual wide band O2 sensors.
Thanks for your comment.
Cheers,
John
fieroguru NOV 13, 05:34 AM
That is basically the same exhaust setup the SBC guys have ran for years, so it will fit and work.

Not sure about the 3800 ecm, but the early 411 ecm for the LS1 engines had the option within the calibration of assigning specific cylinders to one or two O2 sensors. If the 3800 ecm has the same option, then switching to dual O2 wouldn't be that much of an issue. The Camaro 3800 likely had dual O2s.
pmbrunelle NOV 13, 08:36 AM
In the logical design order of a car, figuring out a good exhaust system is more difficult than adding I/O to the computer.

Adding computer requirements to the exhaust puzzle could result in unnecessary compromises for flow, heat, etc.

In my mind, it makes the most sense to figure out the best exhaust system, and then adapt the computer to the exhaust.

Every department needs to make concessions to each other... not just one sticks to their way, and then the others bend over.
Dennis LaGrua NOV 13, 10:15 AM
John's work is both creative and well done. He has some unique products to offer and they all look to be of high quality.
As for the proposed 3800SC exhaust system I would like to add the following comments hopefully taken in a positive way.
The 3800 exhaust can be a tight fit. One problem area is to allow enough space for the header to clear the A/C compressor and the A/C hoses. Another concern I have is retaining the heat shield and sound. My exhaust uses the Spintech crossflow muffler which makes the interior exhaust noise just about bearable and installs without any trunk cutting or loss of the stock trunk heat shield. I also doubt if you can get by with one O 2 sensor making the use of a crossover pipe mandatory. The last item is power and the effectiveness of this system to be better than stock. All of the above will play into the cost vs gain equation.

------------------
" 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 11-13-2020).]