Porting Plenum and TVS Inlet - recipe for disaster?

[Brian Z.]

As I've posted elsewhere I'm going to be installing my new 123mm cj maf and cj throttle body and then getting it dyno-tuned in the Spring. I'm considering pulling the plenum and porting it along with the TVS inlet to allow more flow. I'm not planning to go crazy on the porting and will certainly do my porting homework ahead of time but is there a chance of this being a very bad idea?

I should be around the 650 to 670 rwhp range with the tune and thought opening the plenum and inlet up a bit might help.

Not really interested in buying a new plenum right now. I thought I read somewhere that L&M might be coming out with a new plenum port matched to the tvs but I don't know if that's out yet and don't know if I can really spend anymore money right now on parts.

Thanks in advance.

[TOMMY GUN]

Originally Posted by Brian Z.

As I've posted elsewhere I'm going to be installing my new 123mm cj maf and cj throttle body and then getting it dyno-tuned in the Spring. I'm considering pulling the plenum and porting it along with the TVS inlet to allow more flow. I'm not planning to go crazy on the porting and will certainly do my porting homework ahead of time but is there a chance of this being a very bad idea?

I should be around the 650 to 670 rwhp range with the tune and thought opening the plenum and inlet up a bit might help.

Not really interested in buying a new plenum right now. I thought I read somewhere that L&M might be coming out with a new plenum port matched to the tvs but I don't know if that's out yet and don't know if I can really spend anymore money right now on parts.

Thanks in advance.

L&M does have a plenum out already. It's available in the BVM Store in my sig.
.

[Joker]

As for pulling the plenum and port matching it, just do it. I finally did it and am glad that I did. As for it being a bad idea, I don't see how it could be. Just make sure that you don't get shavings into the rotors and you should be fine.

[Brian Z.]

Thanks Joker I think I will do that. The L&M is very tempting though. I guess between installing the killer chiller and other parts I've purchased if I don't have time to port the plenum before my dyno session I'll go with the L&M, otherwise I'll put my dremel to good use.

Tommy that fore precision 8.8 cover that is on the front page of the BVM site is a work of art. Wish I didn't already have the FMS cover.

[TOMMY GUN]

Originally Posted by Brian Z.

Thanks Joker I think I will do that. The L&M is very tempting though. I guess between installing the killer chiller and other parts I've purchased if I don't have time to port the plenum before my dyno session I'll go with the L&M, otherwise I'll put my dremel to good use.

Tommy that fore precision 8.8 cover that is on the front page of the BVM site is a work of art. Wish I didn't already have the FMS cover.

Yeah, that cover is cool. I have the Ford Racing one also.

[Joker]

Originally Posted by Brian Z.

Thanks Joker I think I will do that. The L&M is very tempting though. I guess between installing the killer chiller and other parts I've purchased if I don't have time to port the plenum before my dyno session I'll go with the L&M, otherwise I'll put my dremel to good use.

Tommy that fore precision 8.8 cover that is on the front page of the BVM site is a work of art. Wish I didn't already have the FMS cover.

I'm sorry. I have the L&M Plenum and port matched it. I thought that was what you were talking about porting the TVS with the L&M Vs. not porting it. I have the L&M TB and Plenum and ported it.

Not sure what kind of gains you would see by opening up the stock plenum.

[Brian Z.]

No problem Joker - I might just end up picking an L&M plenum up after all.

Who did the tuning on your car? 682 and 652 are awfully stout numbers and it appears the only difference in our set-ups is the TB since you have the L&M and I have the CJ. You running longtubes? I still have the stock manifolds with off roard xpipe. Again - great #'s!

[Justin@VMP]

Just porting the TVS and stock elbow will not show very large gains. The stock elbow was designed for a stock blower and stock airflow, but the TVS kit has you re-use it. It is a HUGE restriction.

I developed a whole new inlet elbow/plenum for the TVS and stock blower that has a much larger opening and has the turn geometry optimized to keep airspeed equal at the blower opening.



We changed the shape of the opening from an oval to a D-port as the D shape flows more air with the least amount of porting.



Then we also developed a "big" elbow with a lowered floor to take advantage of the cut out area inside the TVS blower.



Once I started getting a ton of air into the TVS I found that the TB was a restriction again, so I developed a dual 72mm TB, which fits our big elbow:



The whole package runs $799 and is available from BVM though I believe not listed on their website yet.

[Joe G]

Originally Posted by Justin@VMP

The whole package runs $799 and is available from BVM though I believe not listed on their website yet.

Correct, thanks Justin.

Business has been busy and I'm behind adding new products to the store.


PM me if anyone is interested in any VMP products that aren't listed.


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[Joker]

Originally Posted by Brian Z.

No problem Joker - I might just end up picking an L&M plenum up after all.

Who did the tuning on your car? 682 and 652 are awfully stout numbers and it appears the only difference in our set-ups is the TB since you have the L&M and I have the CJ. You running longtubes? I still have the stock manifolds with off roard xpipe. Again - great #'s!

I have an initial tune from Justin at VMP and was putting out 660 rwhp with his tune. I have the stock manifolds and the stock Xpipe and cats. I went to AED up by Sacramento and had some additional work done with the porting of the plenum, 80lb injectors, CJ MAF added and had Shaun up there tune it as I was out of time to have Justin do it through Data logging it and the email tunes before Vegas. Justin gave me a great initial tune and was spot on with the stock injectors. Unfortunately by the time I would have gotten a wideband for Justin to get mine spot on it would have been past the time for Vegas with the Holidays.

[Brian Z.]

Well I pulled off the stock plenum and TB. In comparing the stock TB to the CJ TB its obvious why a larger plenum is needed. The stock plenum has an opening that is barely wide enough to accomodate the larger CJ TB.

Now I just need to decide between the VMP and the L&M plenum.

[Joe G]

Originally Posted by Brian Z.

Now I just need to decide between the VMP and the L&M plenum.

Both are on sale:


L&M (click "add to cart" to see sale price) - L&M Airflow Eaton/TVS intake plenum for GT500


VMP (regular sized one since you already have the CJ TB) - VMP GT500 high flow inlet elbow for TVS & stock blower 2007 2008 2009 2010


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[Birdman]

I recommend you go with the L&M ...I did!
Much easier to port match the blower to the L&M, minimal porting required to achieve a port match and maximized air flow.


VMP on Left ....L&M on right

[TOMMY GUN]

Looks like much more volume w/ the L&M.

[Birdman]

Originally Posted by TOMMY GUN

Looks like much more volume w/ the L&M.

....and a straighter air flow pathway... (which means no turbulance and hot spot (yellow & red)on the inside radius as seen in the 3D pic in post#8)

[Justin@VMP]

What's easier is not always better, we had the option to make a plenum that required no porting at all but the value was not there for the consumer.

I won't argue with the so called airflow experts in this thread, all I will say is that CFD modeling backed up with dyno results do not lie.

AFAIK I'm the only one to make 748RWHP with a TVS on a stock bottom end. I also have a magazing article coming out in a few months that shows same day before and after results from installing our elbow and 72mm TB on a car that already had a competitors product on it.

[dwattsup]

Originally Posted by Joker

I have an initial tune from Justin at VMP and was putting out 660 rwhp with his tune. I have the stock manifolds and the stock Xpipe and cats. I went to AED up by Sacramento and had some additional work done with the porting of the plenum, 80lb injectors, CJ MAF added and had Shaun up there tune it as I was out of time to have Justin do it through Data logging it and the email tunes before Vegas. Justin gave me a great initial tune and was spot on with the stock injectors. Unfortunately by the time I would have gotten a wideband for Justin to get mine spot on it would have been past the time for Vegas with the Holidays.

I think your car is a little bit of a freak. I have the same setup, except that I'm running a 2.6 pulley with 1 more lb. of boost and the best Shaun could get out of my car was 674rwhp/638rwtq. That's good enough for me, at least for now. Your gears I believe are 3.55 and I'm running 3.73. I think you also have a little smaller tire diameter. It is interesting that he did need to tune my idle with the L&M TB. It just wouldn't idle right with the GT500 stock setting. I believe yours is set at the stock settings.

[Brian Z.]

dw - I notice your tune was on 91 octane. I wonder if Joker's was on 93 which, if so, could account for a bit of the difference. I'm with you though, his numbers are a bit freakish and I'm assuming I'll be at about where you are when I get my car tuned in March.

[428cj]

I went with justins big D port elbow on my tvs I 'am 100 % pleased 265 upper 10% I.W bal 80 injectors went with l/m 66 th body and c/l intake with hpx maf wish I had went with justins 72 th body 428 cj

[dwattsup]

Originally Posted by Brian Z.

dw - I notice your tune was on 91 octane. I wonder if Joker's was on 93 which, if so, could account for a bit of the difference. I'm with you though, his numbers are a bit freakish and I'm assuming I'll be at about where you are when I get my car tuned in March.

We live in California and 91 octane is the normal grade for premium. I'm pretty sure he was running 91. They have race gas in the shop, but I didn't have time to refuel and retune. Shaun was a little surprised that I didn't make quite as much power as Robert (Joker), but every car is a little different. I hope your tune goes well, good luck with it!