Turbo cam recomendation from Cam Motion
03-19-2007, 07:35 AM
#42
Originally Posted by RealQuick
Subcribing....
FYI ... I will be using a 24/224 .573/.565 114LSA cam on my 383ci LTX setup with a T88.
FYI ... I will be using a 24/224 .573/.565 114LSA cam on my 383ci LTX setup with a T88.
Mike
03-19-2007, 07:39 AM
#43
Originally Posted by engineermike
You should try your 230/236 cam in there first and see what happens. I've been contemplating swapping from my 224/236 to a 230/236.
Mike
Mike
Damn its been a long time. I had a custom ground BRE cam I was gonna use with an S trim (Original build was gonna be S/C). The specs were 23x/24x on 116, I could have kept for the trbo setup, but I sold it. The guy that has it now made 700rwhp with a 355ci T trim setup (I think at only 15psi). 
03-19-2007, 09:01 AM
#45
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This is interesting info. Jim is the only one that has done testing that I have talked to directly, and I can't remember (My age!!) what he said.
Jim, can you tell us what et/mph you ran with each cam as well as how fast each cam recovered on the gearchange. What gear splits you used would be helpful also as tighter gear splits can get away with more camshaft in our testing.
Kurt
Jim, can you tell us what et/mph you ran with each cam as well as how fast each cam recovered on the gearchange. What gear splits you used would be helpful also as tighter gear splits can get away with more camshaft in our testing.
Kurt
03-20-2007, 11:04 AM
#46
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Originally Posted by dhdenney
I've been playing with Pat Kelley's calculator and Comp's lobe catalog. I'm having a hard time deciphering a relationship between LSA and centerlines. I know you average the centerlines to get LSA but Comp's lobe catalog doesn't say much about centerlines. If you have an intake and exhaust centerline of 113 then LSA is 113 right? But if you have an intake centerline of 110 and an exhaust of 116 then you still get 113. Am I doing that right?
yep. LSA is a fixed aspect of the cam. you can advance/retard the cam (advanced 3* in your hypothetical case)...but the LSA remains the same
03-20-2007, 12:03 PM
#47
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Originally Posted by Fireball
yep. LSA is a fixed aspect of the cam. you can advance/retard the cam (advanced 3* in your hypothetical case)...but the LSA remains the same
Yeah I did some more searching and found some more info on advance and retard so I edited my post before you had even replied.
03-20-2007, 12:56 PM
#48
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OK I just received a recommendation from Comp (which is a surprise cuz I did that like a month ago and never heard from them). It says:
The specs will be as follows/236/238/.602/605/HR115+4
Will pull from around 1800-6800 rpms strong with the turbo set up
With trying to achieve that much RWHP is gonna be hard with something straight of idle! I think this cam will do real well. This cam with that cubic inch will probably come in around 3200-7000 rpms.
That looks like the XE-R lobes to me. Total lift will be .620"/.623". Heads will be flowing almost 290 cfm with my 4" bore so I guess that would be ok. My calculator says this cam at .050" is:
IVO: 7 BTDC
IVC: 49 ABDC
EVO: 58 BBDC
EVC: 0 ATDC
with an overlap of 7.
I was playing with the calculator and the catalog and came up with something but have no idea how far off base I might be. It was a 228/228 113 lsa and 0 advance. Lift was .605" on XE-R lobes as well. I picked XE-R lobes for better under curve power and 0 advance for a little more top end out of the shorter duration cam. Valve events at .050" were:
IVO: 1 BTDC
IVC: 47 ABDC
EVO: 47 BBDC
EVC: 1 ATDC
with an overlap of 2.
The specs will be as follows/236/238/.602/605/HR115+4
Will pull from around 1800-6800 rpms strong with the turbo set up
With trying to achieve that much RWHP is gonna be hard with something straight of idle! I think this cam will do real well. This cam with that cubic inch will probably come in around 3200-7000 rpms.
That looks like the XE-R lobes to me. Total lift will be .620"/.623". Heads will be flowing almost 290 cfm with my 4" bore so I guess that would be ok. My calculator says this cam at .050" is:
IVO: 7 BTDC
IVC: 49 ABDC
EVO: 58 BBDC
EVC: 0 ATDC
with an overlap of 7.
I was playing with the calculator and the catalog and came up with something but have no idea how far off base I might be. It was a 228/228 113 lsa and 0 advance. Lift was .605" on XE-R lobes as well. I picked XE-R lobes for better under curve power and 0 advance for a little more top end out of the shorter duration cam. Valve events at .050" were:
IVO: 1 BTDC
IVC: 47 ABDC
EVO: 47 BBDC
EVC: 1 ATDC
with an overlap of 2.
Last edited by dhdenney; 03-20-2007 at 01:37 PM.
03-20-2007, 01:12 PM
#49
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hmmm im doing wheelies with a t76gts and a turbo cam from cam motion that is 218 214 564 546 115 lsa however that is on a 346. i will be going alot bigger for the 370....
03-20-2007, 01:24 PM
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Originally Posted by Mr_president
hmmm im doing wheelies with a t76gts and a turbo cam from cam motion that is 218 214 564 546 115 lsa however that is on a 346. i will be going alot bigger for the 370....
03-20-2007, 07:15 PM
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Cam Motion replied today and stated they felt the reverse split they recommended was optimal for my combo. I'm just gonna tell them to charge me $25 and forget that one.
03-20-2007, 07:36 PM
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Originally Posted by stevewix
mine is a 230/220 .580-ish lift on a 117 LSA; I wish it were bigger...
...This car idles like my pickup
...This car idles like my pickup
03-20-2007, 07:52 PM
#54
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Originally Posted by dhdenney
Interesting. Who spec'd that cam? Does it make good power?
Anyhow, it makes great power - i think on my 370 it peaks around 6000; I've had so many issues that got sorted out in the last month this is honestly the first clean pass i'll make...
With my TH400 slippage calculated to the 25-30% range (turned out to be the tranny cooler) it went 6.35/110.5 in the 1/8th (just over 4000LB raceweight). 16 psi, 19 degrees timing. It runs good for how small it is...
This season will be the real test
03-20-2007, 08:13 PM
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I wasn't real keen on that reverse split from the beginning. I'm thinking that the Comp recommendation is probably what I'll get. I'm just waiting for some 'yays' or 'nays' here in this thread.
03-20-2007, 08:55 PM
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Originally Posted by engineermike
I say "yay" on the Comp cam, or if you want more power get a clone of the Speed Inc 370/T88 cam that's dyno-proven to make ridiculous power in a very similar combo.
Mike
Mike
03-20-2007, 09:05 PM
#58
Originally Posted by dhdenney
What do you think of the 115 lsa vs. the 112 lsa of the Speed Inc cam?
Speed Inc 236/242-112, +4
EVO: 57 BBDC
EVC: 5 ATDC
IVO: 10 BTDC
IVC: 46 ABDC
Comp 232/234-115, +4
EVO: 58 BBDC
EVC: 0 ATDC
IVO: 7 BTDC
IVC: 49 ABDC
IVC and EVO are very close, so you can expect the rpm range to be very similar. The biggest difference between these two is in the overlap area, where the Comp cam has 7 deg and the Speed cam has 15 deg overlap. We can be sure that if your backpressure is <5 psi higher than boost, then more overlap will only help power by better filling the cylinder. We can also be sure that the Speed cam will have a rougher idle. The unknown here is how high is your backpressure in relation to boost, and how will that affect the benefits of added overlap.
Mike
03-20-2007, 09:22 PM
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Originally Posted by engineermike
Look at valve events NOT LSA. Heck, the stock turbo GN cam is on a 106 LSA.
Speed Inc 236/242-112, +4
EVO: 57 BBDC
EVC: 5 ATDC
IVO: 10 BTDC
IVC: 46 ABDC
Comp 232/234-115, +4
EVO: 58 BBDC
EVC: 0 ATDC
IVO: 7 BTDC
IVC: 49 ABDC
IVC and EVO are very close, so you can expect the rpm range to be very similar. The biggest difference between these two is in the overlap area, where the Comp cam has 7 deg and the Speed cam has 15 deg overlap. We can be sure that if your backpressure is <5 psi higher than boost, then more overlap will only help power by better filling the cylinder. We can also be sure that the Speed cam will have a rougher idle. The unknown here is how high is your backpressure in relation to boost, and how will that affect the benefits of added overlap.
Mike
Speed Inc 236/242-112, +4
EVO: 57 BBDC
EVC: 5 ATDC
IVO: 10 BTDC
IVC: 46 ABDC
Comp 232/234-115, +4
EVO: 58 BBDC
EVC: 0 ATDC
IVO: 7 BTDC
IVC: 49 ABDC
IVC and EVO are very close, so you can expect the rpm range to be very similar. The biggest difference between these two is in the overlap area, where the Comp cam has 7 deg and the Speed cam has 15 deg overlap. We can be sure that if your backpressure is <5 psi higher than boost, then more overlap will only help power by better filling the cylinder. We can also be sure that the Speed cam will have a rougher idle. The unknown here is how high is your backpressure in relation to boost, and how will that affect the benefits of added overlap.
Mike
03-20-2007, 09:31 PM
#60
Originally Posted by dhdenney
And backpressure will remain pretty much unknown since the car is not built yet. Thanks for all your insight.
With a combo like you are building, you've surely read up on turbine-induced backpressure, it's affects, and how the cid and turbo size affect it.
On 377 cid, we've been able to get backpressure down to 26 psi at 18 psi boost. That's a 8 psi split using a T76GTS turbo and a 3.5" downpipe with no muffler. The GT4780 is a much larger turbo with a huge exhaust side, plus your engine is smaller, both of which help the backpressure/boost relationship. If you have a decent routed exhaust and straight-through muffler, good flowing intercooler and throttle body, I dare say your backpressure may match boost 1:1. Some of the guys with more experience on large turbo's will know more about this than I - people like INTMD8 and Jose. If you can match backpressure/boost, then you really can't go wrong by adding overlap.