Finished manifold finished pics up. The ports look rough although they are very smooth and were finished with 400. I used a dremel to cut down the casting, then hit the runners with 60 grit followed by 100.
Cobra Jet manifold reworking
- Thread starter 01bluesnake
- Start date
Sub'd... Great clean-up job!
We would like to compare the stock and ported version. But it all depends on how much time it takes us to make pulls, swap four intakes over, swap three throttle bodies as well as how much money we want to put into this. Because all this is coming out of our pocket. Dyno time is not cheap and neither was collecting all these parts.
As of right now I think this is how the testing will go down. Drew and I have to take about prioritizing the list so that we get certain things done for sure.
1. Stock intake w/ Airaid CAI.
2. Boss intake w/ Airaid CAI
3. Cobra Jet intake (stock) w/ FRPP SCJ oval throttle body & custom 4.5" CAI
3. Cobra Jet intake (stock) w/ FRPP dual 63.5mm throttle body & custom 4.5" CAI
4. Cobra Jet intake (stock) w/ Stock GT500 throttle body & custom 4.5" CAI
5. Cobra Jet intake (cleaned port) w/ FRPP SCJ oval throttle body & custom 4.5" CAI
6. Cobra Jet intake (cleaned port) w/ FRPP dual 53.5mm throttle body & custom 4.5" CAI
7. Cobra Jet intake (cleaned port) w/ Stock GT500 throttle body & custom 4.5" CAI
Seven different configurations is a lot to squeeze in one day. So like I said, we will prioritize this and do what we can. We will have all the raw data from the runs. So we will be able to make dyno graphs comparing anything we wish to.
We will be using my car for this test. It has a stock GT motor, stock exhaust manifolds, Jegs cat delete pipes, Borla X pipe & over the axle tubes and JBA mufflers. The car will have AED tunes for the different intakes and MAF housings. Should be a good time. I know the two of us are up to the work and excited to see the results. :beer:
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Thanks for doing this!!!!!
No problem. We had fun when we did the same thing with the stock versus boss intake as well as the stock CAI and the Airaid CAI. This should be a lot more fun because the numbers should be quite different with the CJ to stock & Boss intakes.
As long as things go smooth it should be a blast. After this is done I hope we get some good weather. Because I really want to better my best ET of 11.44. :rockon:
As long as things go smooth it should be a blast. After this is done I hope we get some good weather. Because I really want to better my best ET of 11.44. :rockon:
Yes thanks for doing this...im excited!!
Def excited for results!
Yep, once the test goes down, ill make a thread specific to the testing results with a link back to here for the ported manifold process in case people are curious to what was all done to it.
This is gonna be fantastic
This is an awesome test. Thanks!!
Now I can get a good idea on how the gt 500 tb stacks up to the frpp unit.
Now I can get a good idea on how the gt 500 tb stacks up to the frpp unit.
Subbed!
Sub'd
You mean the CJ 63.5mm TB : )
I would personally skip this one to safe time since they are no longer available...
I am in for your results since we don't have any of our own just yet. Soon! :beer:
Sorry, typing error. Yes, it is the 63.5mm. Drew (01bluesnake) bought a used one for his car already. That is why I am sure he will want to dyno it to see how it stacks up.
If I can borrow or buy a cheap used FRPP 123mm MAF housing we can test that as well. I have 5" tubing and couplers in the garage. And I can borrow the air filter off my Capri. So it wouldn't be hard to fabricate up. hmmmm
If it's 123mm you are looking for you can use the MAF part of the GT500 tube from JLT. The FRPP one is 140mm if I remember correctly. The price is insane for those...but a quality piece no doubt.
While researching and engineering the correct CAI diameter, I went through the following calculations to see where the true bottleneck is and what’s really required based upon it. Obviously airflow through a pipe is dependent upon the surface area of that pipe, so I decided to do a comparison of various throttle bodies – actual surface area of airflow. What I found was pretty astonishing; the SCJ TB is in a league of its own for serious flow area. The 4.5 inch seems to be the best combination of flow, drivability and nicest transition to the 5 inch OD on the TB without restriction. 5 inch is overkill based on the TB constraint. The 4 inch and 4.25 inch should theoretically make the same power as the 4.5 inch, but it’s more of a step down at the TB. I can clearly see now why the 4.5 inch made 10 more hp than my JLT. I’d also like to bet that the CJ dual 65 with any CAI being at 9 square inches is 10-15 hp less than the SCJ and 4.5 inch CAI. I’m glad I went with the SCJ.
Throttle body intake side surface areas:
GT500 Dual 60mm = 8.77 sq in minus throttle plate rail area (1.18 sq in) = 7.59 sq in
Dual 63.5mm = 9.82 sq in minus throttle plate rail area (1.25 sq in) = 8.57 sq in
For reference: Single 90mm = 9.86 sq in minus throttle plate rail area (0.88 sq in) = 8.98 sq in
CJ Dual 65mm = 10.29 sq in minus throttle plate rail area (1.27 sq in) = 9.02 sq in
SCJ Mono-Blade TB = 13.78 sq in minus throttle plate rail area (1.45 sq in) = 12.33 sq in
CAI round pipe surface areas:
5 inch = 19.63 sq in
4.5 inch = 15.90 sq in
4.25 inch = 14.19 sq in
4 inch = 12.56 sq in
2010 JLT at tightest spot = 10.01 sq in
Throttle body intake side surface areas:
GT500 Dual 60mm = 8.77 sq in minus throttle plate rail area (1.18 sq in) = 7.59 sq in
Dual 63.5mm = 9.82 sq in minus throttle plate rail area (1.25 sq in) = 8.57 sq in
For reference: Single 90mm = 9.86 sq in minus throttle plate rail area (0.88 sq in) = 8.98 sq in
CJ Dual 65mm = 10.29 sq in minus throttle plate rail area (1.27 sq in) = 9.02 sq in
SCJ Mono-Blade TB = 13.78 sq in minus throttle plate rail area (1.45 sq in) = 12.33 sq in
CAI round pipe surface areas:
5 inch = 19.63 sq in
4.5 inch = 15.90 sq in
4.25 inch = 14.19 sq in
4 inch = 12.56 sq in
2010 JLT at tightest spot = 10.01 sq in
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