OK, here's the results in a nutshell. I picked up about 6-7 rwhp over my trusty TR224 cam (both power peaks at 6100 rpms), and gained 35-60 rwhp at higher rpms with no loss in low or mid-range torque and no loss in driveability. Here's a breakdown of what I changed:

Before: Thunder Racing 224/224, .564/.564 112 LSA cam (4 degrees of advance ground in).
Best dyno run with converter locked: 407 rwhp @ 6100 rpms and 390 rwtq at 5000 rpms (385 rwtq between 4400 and 5200 rpms).
Best dyno run unlocked: 390.4 rwhp (390 from 5800 rpms to 6600 rpms)

After: Thunder Racing 230/224, .569/.564 111 LSA cam (2 degrees of advance ground in).
Best dyno run with converter locked: 413.7 rwhp @ 6100 rpms and 390 rwtq at 4900 rpms (torque curve was an overlay of the 224/224 cam until 5800 rpms).
Best dyno run unlocked: 395.5 rwhp

Here's the dyno sheet: http://www.converter.cc/TR230-224dyno.jpg
About all I can tell you is that the hp curve is an overlay of the 224/224 cam until 5800 rpms, then is starts to pull away. The power curve is completely flat, not falling below 400 rwhp until 6800 rpms. At 6600 rpms, the 230/224 reverse split cam is still in the 410 rwhp range while the 224/224 is down to about 375 rwhp. At 6800 rpms, the 230/224 has 395 rwhp and the 224/224 is down to 335 rwhp. So if you were willing to shift the motor around 6600-6800 rpms, you're going to be rewarded with 35-60 more rwhp. But at the true power peak (6100 rpms for both cams), the "reverse split" cam is only worth about 6-7 over the awesome TR 224/224.

Do I think the change was worth it? Hell yeah! The idle sounds much better now with a 900 rpm idle. More like my old Lunati 221/224 113 LSA cam. These super fast Thunder Ramps make the idle characteristics of a 230 cam nearly the same as an old Lunati ground T1 cam (the latest MTI grinds have faster ramps BTW). By keeping the exhaust lobes smaller, driveability is about the same as the TR 224/224 cam and the sound is much better. Not too bad for a heavy *** convertible with SAM's first version of Stage II heads (dating back to '99), automatic and 3.73 gears.

<small>[ April 22, 2002, 07:44 AM: Message edited by: Patrick G ]</small>

 

Looks good! The question I now have is would you have been better or worse off with a 230/230 version of the same camshaft.

 

Great question Terry. The idea of the reverse split is to give the LS1 more breathing potential without compromising driveability too much. The exhaust, especially with ported heads and big headers, is almost too good in comparison to the more restricted intake. Hard to say if a 230/230 would make more power. Easy to tell you it would idle worse and have poorer street manners. That's one of the supposed advantages of the "reverse split" cam.

 

Very nice numbers Patrick! Glad the cam is working out for you. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

so the theory actually worked then patrick.
i would like to see the car again, see how it sounds now after the cam swap.

stop by some time if you get a chance bud.

steve frank

 

Would it even be beneficial to spin it as high as 6800rwhp since the peak is at 6100?? I would think a 6500rpm shift would be enough?? I would think this would be great for someone with 4.10's who is worried about running out of gear at the end of the track...

I'm assuming a 114 LSA would be a bit peakier if thats even possible, have less midrange, be more likely to pass emissions and might even idle better??

Wanna make sure I'm on the right path here.....

This cam would have a tough time passing emissions on a stock cubed fbody, correct?

<small>[ April 22, 2002, 03:59 PM: Message edited by: verbs ]</small>

 

That is a awesome comparison Patrick... Being able to show the difference between the two gives people more options when it comes to cams.. That would make for a killer strip setup on a M6 with 4.10's.. You would be able to stay into it instead of shifting to continue receiving the power..

 

Great info!
<img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

FWIW, I'd shift by 6500-6600 to save the bottom end.

<small>[ April 21, 2002, 09:08 PM: Message edited by: MelloYellow ]</small>

 

Thats some awesome power. Damn this is making my decision harder and harder on what cam to pick. All these cams are putting out alot of power.

 

Thats insane!!!!!!!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> I thought you were joking to start with. 35-60 rwhp with only 6 more degrees duration <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

Time to try the 234/224 <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

J.

 

Wow that's awesome, especially if you'll spin the motor to 6800.

Why the huge bump up in idle speed? You were around 750 last I heard you on the cell phone. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Did this cam require it or were you ready for stealth.

Just curious, how do you think the comparison of the TR 224 on a 114 LSA would have held up in the upper end compared to the 230/224?

 

Joel (Ragtop),

I had my idle raised to 900 rpms when I got dyno tuned at Thunder Racing a few weeks ago. The 900 rpm idle was a little high for the TR224 cam, but it's just fine for the TR 230/224 cam. If I had started with the TR224/224 cam on a 114 LSA, I think the power peak would have been the same number, just 100 rpms higher than the same cam on a 112. The 111 LSA makes the motor have torque EVERYWHERE...even at really high rpms. Can't believe this cam pulls so well up high, while still making peak power at a very "sane" 6100 rpms.

 

It would be nice to see the flow numbers on your heads. I know most porters are finding a ton of flow in the exh, so that would make sense that your engine is doing so much better now.

It also seems as though you have a better combustion than before with higher cylinder pressures. This will make your car like the lower exh duration also.

One more thing is that it is definately telling us that the LS1 is restricted on the intake. If that was a better flowing system then you would most likely have less intake duration also.

Bret

 

How would this cam react to some NOS.

 

OK, here's the dyno sheet: http://www.converter.cc/TR230-224dyno.jpg
Keep in mind, there are a few blank spots in the print-out, but the lines were smooth nontheless. Dyno run number 9 was the best run with the 224/224 cam and dyno run 12 was the best with the 230/224 reverse split cam.

This cam would work fine with nitrous, but a conventional split duration cam 224/230 would go along more with conventional thinking. <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

 

Those are some interesting changes Patrick. The increased intake duration really seemed to help your heads/intake out. I'd say the swap was definitely worth it in your case, now your HP curve doesn't fall off a cliff like it used to. The graph actually looks like it should now, so that is nice!

Also nice to see no sacrifice in lower/midrange power. I wonder how a reverse split will react in a larger cube motor? Might help out with the restrictive intakes on our cars.

Tony

 

Tony,

I think a "reverse split" duration cam would help a Super Stroker even more than a stock displacement LS1 because they are more intake restricted. You go with super high flow MTI Stage III exhaust ports, 1 7/8" Dyna Tech headers, and free flowing catback, you won't be exaust restricted. Trying to get all that air through a stock LS6 intake manifold and small intake runners is going to be a bigger challenge IMO.

A S1 cam with 6-8 additional degrees of intake duration on a 110-111 LSA would be muy nice!!

 

Thats AWESOME!! I KNEW it would work. I wonder if you could pass emissions in this setup?
I wonder what a 234/226 cam would do for us guys with MAC headers?
I think a 112LSA might bring the powerband up to around 6400rpm as well with the added intake and exhaust duration...
Cheers,
Chris

 

I don't know John, I think the motor picked up more without a lot of degradation in idle quality. I think the gains with a 230/224 would be bigger than going to a 227/227 (which might have a similar idle quality). I didn't see a lot going from a 221/224 to a 224/224. You may not have seen a lot going from a 222/222 to a 224/224 (even with the faster lobes). A 230/230 might make more power (or might not), but it would definitely idle worse and possibly lose some low-end torque (which this cam did not). Hard to say, but I wanted to try something different.

I wouldn't call the early SAM heads a poor intake design. They were good enough for 10.8s in Judson's SS (with stock displacement and full weight). They're just not up to the 2002 standards that all the good shops are putting out these days...especially the ported LS6/6.0L stuff...that stuff rocks!

Patrick

 

Why do people think that the intake lobe must match the exhaust lobe? You have two different things going on here, wildly different pressure differentials ( exhaust pressure differential is going to be much greater than the intake side ), and different things going on.

For example open the exhaust earlier, you start blow down earlier in the powerstroke and you decrease overlap ( wider lsa ).

Open exhaust later, you start blowdown later in the pwoerstroke, and increase overlap ( narrower lsa ).

Other way to do this is juggle the lobe durations around.

If the exhaust is good, it could be possible, you don't need to throw power away ( bigger exhaust lobe ).

There are some ford race heads which run 2.15" intake valve and 1.55" exhaust valve. Reason being exhaust pressure differential is GREAT, all that heat and pressure just wants to jump out of the cyllinder.

Also tightening down on the lsa helps the exhaust system to assist the induction system.

You can't fight resonance tuning, so once you break past the intakes tuned harmonic frequency power is going to be harder and harder to come by every rpm - ask all the gt40 intake'd na ford guys.

Chevies are at a better starting point with 14" runner, but for these guys trying to get power at the last 1000 rpm of the range they might need 10-12" larger runner.

Holley not going to fit the bill since its just a recast ls6 intake in alum. Can port it, but runner length is still going to shut you down, and how far can you port it?