Well its probably cam changing time, the 232/236 114 is a little big for me, at least if I stay with stock cubes. I like its top end pull, but it needs a 1000 rpm idle and I can't get rid of the occasional surge in 1300 - 1400 rpm range.
The previous cam was a 224/224 114 which had decent manners (900 rpm idle and no surge at 1200), but I'm trying to stretch a little more power out and use a 900 - 950 rpm idle with no surge at 1300 so I was thinking of a comp XE-R:
228/228 115 +4
or
226/230 115 +4

I'm pretty sure the 228/228 114 has been run sucessfully and probably would meet my drivability criteria. However, I'm somewhat curious to see what a 115 LSA would do, if anything. Could I drop the idle back another 25 - 50 rpm? Does the increasse in LSA defeat the gains from increasing duration?

So what happens when you combine a lot of duration with a high LSA?

<small>[ December 12, 2002, 08:15 PM: Message edited by: Ragtop 99 ]</small>

 

My buddy Joey runs a 228/228 lsa 112 cam I think and he runs 11.0's at I think 120mph with 3.23's and a stall.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Ragtop 99:
<strong>So what happens when you combine a lot of duration with a high LSA?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You shift your car really high.

 

Joel, I'm by no means an expert...but here goes

could you try something along the lines of the TR 227/224 114 ( with maybe more lift for your heads )

it should idle well, make good power to 6400, and let u shift no later than 6800 or so....

-Alex

 

What happens when you widen the LSA by 1 degree is that you lose 2 degrees of valve overlap. This means the car will idle slightly better, and throttle response at lower RPMs will be slightly smoother.

Theoretically, the wider LSA will make the power band start slightly earlier, and it will maintain power slightly longer after peak HP is reached. Peak HP and TQ will be slightly lower. However, with only one degree of difference in LSA, the net effect will be very minimal.

 

I don't have a problem shifting high. I have an ARE shortblock and use 6800 with my current cam. As long as I get a nice wide torque curve, I'm fine with shifting high. I need to be able to have good torque (not peak) by 4000 rpm and my shift extension is well over 5000 rpm, so high end power is ok. I know that shifting the power curve down would be best for maximum ET, but I also enjoy spinning the motor up in 2nd & 3rd gear on country roads when I can't get to the track.

Vice: what rpm or speed is your buddy using for lock-up?

Alex, I think ARE big valve heads like mine respond better to single or traditional split patterns.

 

Joel - I think the 228/228 114 LSA cam would be a great choice. I'm running our 228/228 on a 111 LSA in my A4, and I LOVE it. My peak HP is right at 6,400, and it carries it out to 6,600 before starting to drop off. My old 224/224 112 LSA cam only had two degrees of advance ground in, and it peaked at 6,550 RPM. My current 228/228 has 3 degrees ground in, FYI. You won't have a problem with targeting a 900-950 RPM idle with this cam, especially on a 114 LSA. I have mine idling at 850 RPM. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> The only time I have any surging issues is when the car is cold. Once it is up to temp, I do not have any problems whatsoever.

You'll pick up some drivability over the cam you have now, and you'll still be able to wind the engine out without it running out of breath. I think it will work out well for you. Besides, now is the time to buy a cam since we're having a cam sale! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Trevor

 

That cam is going to rock for you! First, it will have a smooth idle for a 228 cam (wide LSA & fast XE-R lobes). I do not think this cam will have as high of a power peak as some will say. With an intake closing point of 45 degrees ABDC, you are in the ideal range of making kickass power with a 346. You should make peak power at about 6200-6300 and it will carry nicely past 6800. Although you might give up 5 rwhp peak power vs going with a narrower LSA cam, you will be 5 rwhp stronger at 5000 rpms and 6500 rpms than a 112 LSA cam. Basically, you will give up a little peak power, but have a broader, flatter power curve. Just the ticket for an automatic and a Pro Thruster converter. I say well done!

 

I had a 228/228//111 back in 2000 and it was fun and with tuning it ran okay.

I think a 228//228//115 would idle like a B1 but you'd have to advance it for sure to keep the peak from being too high.

 

Comp XE-R 224-228 581-588 113LSA in straight up...
Nice broad power with a peak of 6500....

JS

 

Ask Terry Burger about his MMS 229 cam. He had one in his stock cubed engine runnin 10s. Its a single pattern cam with .578" lift and 230 duration at .050" lift with a 114 LSA.

 

PSJ: 4 degrees of advance is the plan.

Dug: The MMS cam is what made me think that it would work. It runs close to 230 duration on a 114, so my guess is a 228 on a 115 would perform close, but have slightly better drivability.

 

Rag

Those are the correct numbers for the the mms229 cam. I bought one used and those were the numbers on the cam card. I havent installed it yet so I cant tell you anything about the idle quality. Some say its smooth some say its rough. Probably a matter of tuning and idle speed. I have a M6 so it doesnt really matter. If youre interested, MMS has a dyno of that cam on their website. Its in a z06 corvette.

Good Luck!

<small>[ December 13, 2002, 09:19 PM: Message edited by: dug ]</small>