offaxis

iTrader: (19)

Hey guys I am currently am running a comp
224/224 .581/.581 116 LSA
The car makes good power right now but it peaks around 6000-6100 then drops off hard . I like the smaller cams with a smooth idle . I was just wondering if anyone has any Ideas on another cam that might pick up all around and alow me to peak around 6500-6600
My current motor setup is

aes 390 shorblock
As Cast Trick flow 220 heads
ls6 intake ( I have a fast 102 Im installing this week)
c5r timing chain
APS extreme twin turbo kit
4l80 trans
9 inch rear 325 gears

I was thinking of a 230/230 115 lsa cam but I am worried about idle quality

David A. Cates

A 230/230 115 has 0* of overlap, so the idle will be mild, but shouldn't be a problem to tune to idle like stock.

Johnv

What size turbos do you have , power falling off at the top end is just as likely to be turbos running out of steam.

stock48

iTrader: (17)

X2. or maybe ignition or vale float. My little 6.0L, 212/112lsa pulls well past 6500 with either the GT76/94 or PT88/94 but lays over at 5500 with the Tc76/68.

offaxis

iTrader: (19)

Im not exactly sure what size they are. I have the APS extreme kit though and many others on this board run it with 427 engines making up to 1000k. I believe they flow 65# per each. Here is my current dyno sheet. Can you tell from the sheet what is going on. These numbers are through my 4l80 unlocked

Nitroused383

iTrader: (10)

That looks like valve float for sure. I didn't look at your lobe profiles but I bet those are xer lobes? Xer lobes + heavy trick flow valves and probably aftermarket roller rockers will do this. There was a guy on here with a vette who had this same issue I will find you his thread. A lot of n/a guys have issues with your same combo. You have several options.

2000RATA

Curious as to what boost that's at?

I had a custom cam ground for my twin kit as well. One thing the guy said who came up with the profile was "you don't want the cam getting in the way of the turbos." We were speaking about rpm limits. He talked like the cam did not necessarily dictate RPM limits as they do on a N/A engine.

Nitroused383

iTrader: (10)

Found the thread, check it out as he went through alot to solve his issues https://ls1tech.com/forums/forced-in...20-pounds.html

stock48

iTrader: (17)

That is true. You will get more rpm out of a given amount of duration in most boosted applications. We notice this as well on NA engines from altitude to sealevel power pk will raise 3-500 rpm with the extra sea level baro. Same thing with a really efficient set of heads.

offaxis

iTrader: (19)

That was with 18 psi and 15 deg of timing. I made 751 rwhp on 15 psi and 20 deg timing. But When i tried to add the timing back in with 18 psi the tires would spin. The tires were wide but very short. I just put some 325/50/15`s which are 28 inches tall. That should help a bit.

It does not matter what boost I have in it it peaks at the same rpm

offaxis

iTrader: (19)

they are the xer lobes. I am running the harlan sharp rockers too. I am going to swap the cam so the next will be with the XE lobes. What do you guys think?

BTW This car is a friggen beast so its not like Im not enjoying it but I have a feeling I can be doing alittle better than I am right now. OFcourse the unlocked 4l80 and the 9 in and steel driveshaft arent going to help the dyno numbers but I am more interested in the track times and not breaking.

All help and suggestions are very appreciated

2000RATA

Your Dyno numbers look great! That trans and diff are hp eaters.
Normally I am a CompCam guy all the way. When I was researching the "what cam" question the information I found was many of the guys who were throwing down numbers that I liked(big) and were doing it with small twin setups (61's and 62's) were running Bullet cams. This info was acquired from several sources. There is a guy there who is particularly good at specing cams for turbo cars. Especially when you have all the right info like head flow numbers and so on. A custom cam is no more than a shelf cam.
And your rockers are as big a problem as the XER lobes.

offaxis

iTrader: (19)

I broke down and ordered the 230/230 115 lsa on the xe lobes. I got the specs from PREDATOR-Z so I knew i was ordering the right cam ve been Sd tuned for a while but I still have the stock maf in there with the screen stil in it. That will be removed now. Im not sure what kind of gains I will get but I will be posting the results. Hopefully if there was any valve float from the xer lobes the xe will fix it.