SLP 1.85 Rockers with GM ASA Cam
#1
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I was wondering if anyone has used SLP 1.85 rockers with the GM ASA cam?
I was looking at roller rockers but keep finding issues (weight over valve, valve float ect). I was wondering if the slp stock style would be better?
I found a set for $200, 600 wouldn't be worth it in my opinion.
Also I checked PTV .083 exhaust .121 intake when I put it together, does anyone know how much they would change duration?
I have a LS1, PRC Stage 1 heads milled .30, .045 cometic head gaskets, with Howards version of the GM ASA cam. (226 236 .525 on 110 LSA), LS6 intake, 1 3/4 bbk lonetubes, no cats, open borla, 85mm throttle body 85mm maf slp lid, 160 thermostat, underdrive pulley, 42lb injectors, and tune.
I was looking at roller rockers but keep finding issues (weight over valve, valve float ect). I was wondering if the slp stock style would be better?
I found a set for $200, 600 wouldn't be worth it in my opinion.
Also I checked PTV .083 exhaust .121 intake when I put it together, does anyone know how much they would change duration?
I have a LS1, PRC Stage 1 heads milled .30, .045 cometic head gaskets, with Howards version of the GM ASA cam. (226 236 .525 on 110 LSA), LS6 intake, 1 3/4 bbk lonetubes, no cats, open borla, 85mm throttle body 85mm maf slp lid, 160 thermostat, underdrive pulley, 42lb injectors, and tune.
Last edited by mgood613; 01-05-2014 at 05:02 PM.
#2
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The higher ratio doesn't add duration as that is a constant which is ground
into the cam profile. They will somewhat trick the engine into thinking it has
a few degrees as the valve will be moving faster/sooner and ultimately about
.045" more total. Some cams are just ground too aggressively to use those
rockers however that Howard's version should be alright. I would definitely
make sure that your valvesprings are in great shape, and should be duals.
into the cam profile. They will somewhat trick the engine into thinking it has
a few degrees as the valve will be moving faster/sooner and ultimately about
.045" more total. Some cams are just ground too aggressively to use those
rockers however that Howard's version should be alright. I would definitely
make sure that your valvesprings are in great shape, and should be duals.
#3
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Thanks, I did put PAC1218 springs when I installed the heads.
I contacted Howards and they said the rockers would be fine.
I was just kind of curious if anyone has tried this?
I'm not disappointed in the way my setup turned out, just looking to optimizes what I have now. I put down 427rwhp 390 ftlbs
I contacted Howards and they said the rockers would be fine.
I was just kind of curious if anyone has tried this?
I'm not disappointed in the way my setup turned out, just looking to optimizes what I have now. I put down 427rwhp 390 ftlbs
#5
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The higher ratio does affect duration at the valve slightly. But you have enough clearance that there won't be an issue.
I don't know about those SLP rockers, though. They have an upgraded trunion vs stock, so they might be okay.
And as long as you have about 145lbs of closed spring pressure and around 370-400 open, you'll be fine with that cam and rocker combo.
I don't know about those SLP rockers, though. They have an upgraded trunion vs stock, so they might be okay.
And as long as you have about 145lbs of closed spring pressure and around 370-400 open, you'll be fine with that cam and rocker combo.
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#9
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IMO, if you plan to stick with your PAC1218 springs then I'd get back on the dyno ASAP, after the rocker install so you can see your gains and if you're getting any valve float in the upper rpm range, which you should be able to see in dyno graph. If any possible sign of V.F. is seen then get some stiffer springs in there ASAP, otherwise enjoy!
#16
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Sorry to bring this thread back from the dead but I'm thinking about a ASA cam and had a few questions.
With the 1.85 rockers and .525" lift how much extra lift does that translate to ?
With the .045 gasket and .30 mill what length and brand pushrods ?
Has it been tuned yet; what did you put down ?
With the 1.85 rockers and .525" lift how much extra lift does that translate to ?
With the .045 gasket and .30 mill what length and brand pushrods ?
Has it been tuned yet; what did you put down ?
#18
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There are two duration's listed on nearly every cam card, and the durations are based on lift points.
The first is the advertised duration, and that's at the first measurable point off of base line, usually 0.006", or somewhere around there. Changing rocker arm ratio's will not alter this.
But, it's generally accepted that airflow doesn't really start until the valve hits 0.050" of lift. That's where you see the second set of duration numbers. This is the point that's accepted to be where the cam starts working. A higher rocker ratio not only increases the total valve opening, but also how quickly the valve gets to that effective point.
Increasing the ratio increases the effective duration by about 2-3* or so at each end. Many dyno tests have proven it to gain a little bit of power here and there; depending on the rest of the engine, of course.
#19
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Wow thanx SSCamaro99_3 and .boB. This cam makes sense to me. For three months of the year I could drive a 229/239 0.571 cam by only wrenching under valve covers and flashing a new tune. End of summer, throw in the stock rockers and be down 20hp but get extended spring life. It would need seperate tunes right ?
It seems like a designed exhaust could really help this cam. Could someone suggest one ?
It seems like a designed exhaust could really help this cam. Could someone suggest one ?
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#20
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I doubt it. We're only talking a few extra degrees of duration and a little bit of lift. It's not like a whole new cam. If you're very astute, you will notice a small improvement. When I did this to my truck, I noticed some improvement while towing, otherwise it felt the same.
Same thing with the springs. No need to keep changing back and forth. You'll probably create more wear and tear by changing things twice a year. Put them in and leave them there.
Same thing with the springs. No need to keep changing back and forth. You'll probably create more wear and tear by changing things twice a year. Put them in and leave them there.