Hey guys. What are the pros and cons of reverse split dur. and lift. This being on a stock headed ls1,MN6. LS6 intake, LT's, and a pulley. Still has stock catback too. Thanks.

 

More intake than exhaust duration was created to help out the cars with stock intakes and aftermarket exhausts. Basically the intake sees more restriction so you hold the intake valve open longer to try and make up for it.

On a well flowing engine a traditional split is best, at around 4-6 degrees.

 

As usual, it all boils down to the combo. I know of quite a few TR230 or X1 high compression combos inthe 10's.
In a setup that can't get 90/90 but with good exhaust runners and header system, they do shine. It is really a matter of preference on parts used.
Exemple: TR 230/224 with TEA stage 2 LS2/LS6 setups. or MTI 230/227 (X1) and their 2E LS2/LS6 heads.

 

Thanks guys. The one I was looking at has 228/222 588/581 114.5LSA. Good for stock heads and catback? How will it idle and what kind of power can I expect?

 

It will idle very smoothly and not have much lope to it. Decent power over stock, but nothing crazy. A lower LSA would pick up a decent amount of power but it would bump a little more.

 

Yeah, like a 230/227 111+4 with 64cc and .040 => 11.05 DCR and ~8.67 DCR

 

they are also good for turbo bluids if using restrictive ex. manifolds

 

Thunder Racing TR 230/224 111 , I see alot of 11sec cars on here with this cam .

 

My X1 has been good to me. Ive never found a reason to change it. Its real easy to get caught up in the latest cam hype.

 

I wouldn't do it.

There's a reason why proven tuners like Futral Motorsports and LG Motorsports don't offer reverse splits in their shelf-cams.

 

Kraest, what about the "proven" cams from TR that are reverse splits? Also, if you look at the FMS cams specs you'll be suprised to see that at higher lift the duration IS reverse split already.

Ben T.

 

im leaning towards the x1 cam. MTI web page most of the customers are running there 2e/x1 combos and most are putting down 440rwhp.. so i say it works.. wilwaxu busts 10's with that setup.

 

I like mine

 

Reading in your sig it says you have a 3200 vigilante, and Kraest is conjecturing reverse splits are not made by companies like Futral for a reason. I know of a low milage '02 car with a 3200 vig on stock heads that's trapping 112 mph right now with a brand new FM13 (the traditional slit) as of TR track day last Saturday. So, I'd contest that there might not be a huge reason to avoid a reverse split.

With a reverse split you get to push the intake valve closing point back later and extend the power band without changing from any given LSA- all while limiting overlap which for a DD might be good thing.

Also keep in mind that we're getting close to splitting hairs here with this theory. After all, the difference between a 230/224 and a 230/232 could be less than the difference of racing in optimal weather or not.

Ben T.

 

Also, the stock catback isn't going to choke a reverse split cam that bad because it's going to have less overlap. Increased overlap really makes the inadequacies of an exhaust/intake system show up. I've seen a reverse split cam (TR230) make within 3 hp of an open cut out... and the exhaust was a 3" Flowmaster. If you step up the exhaust lobe from a 224 to a 232 and keep the LSA bascially the same (111 vs 112), then you're going to start losing more power as overlap increases and you're going to give up midrange torque.

A chassis dyno proved me wrong and made me come out from under the assumption that a reverse split cam has to have a VERY good exhaust system. Seems like the big picture encompassing overlap makes a larger difference than lack of duration on the exhaust.

The original poster said he still has the stock catback.

There's a reason why "proven tuners" like Thunder Racing started grinding reverse splits.


Ben T.

 

Really. The cam WS6-SRT8 was asking about looks like the Speed Inc grind that they put in one of their employees Vette. I believe it ran well too. The numbers in my sig from my old Z/28 are with early TEA stage 2 5.3's and a TR 230/224. I'd say TR is a proven tuner, and my car was a proven performer.

Bruce

 

go to the dyno thread section. look up gillbots results with reverse split cam and a 4000k stall. hes putting down 399rwhp.. and thats on stock heads with a mid length header...impressive..

 

im a big fan of the MTI X1. Im biased though since at one period in time my car put down 415rwhp and 403rwtq, which i fell is a great number for a cam only car that drives near stock and sound great at idle.

 

The TR230 does ok. As others have said, it is all about combination. Just for the record Mike likes to take cheap shots at us whenever he gets a chance.

 

Here's my results with the TR230: https://ls1tech.com/forums/dynamometer-results-comparisons/476349-tr230-224-a4-dyno.html