My Setup and Crane 1.8's?
11-09-2005, 05:10 AM
#1
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My Setup and Crane 1.8's? How much do you think they would add to my current setup:
TEA Stage 1.5 5.3 Heads Milled 0.010
Comp Cams XE 228/230/571/573 LSA 112
85mm Lid
85mm MAF
Fast 90mm Intake
Nick Williams 90mm TB
0.045 Cometics Head Gaskets
Kooks 1 3/4 Stainless Steel Race Headers
Kooks Y Pipe
ASP Under Drive Crank Pulley
SLP Dual/Dual Catback Exhaust
Flowtech Cutout with McCord Power Plate
K&N Air Filter
Fast Toys Ram Air
4200/2.35 STR Stall
Motive 373's
TEA Stage 1.5 5.3 Heads Milled 0.010
Comp Cams XE 228/230/571/573 LSA 112
85mm Lid
85mm MAF
Fast 90mm Intake
Nick Williams 90mm TB
0.045 Cometics Head Gaskets
Kooks 1 3/4 Stainless Steel Race Headers
Kooks Y Pipe
ASP Under Drive Crank Pulley
SLP Dual/Dual Catback Exhaust
Flowtech Cutout with McCord Power Plate
K&N Air Filter
Fast Toys Ram Air
4200/2.35 STR Stall
Motive 373's
11-10-2005, 04:55 AM
#5
According to my "unofficial" spread sheet of spring loads vs. lifter issues, if you are running stock lifters you would be exceed the open load I would find acceptable and may jeopardize your lifters. This is just my personal opinion based on data I have picked up here on LS1Tech on when people have run into issues with the stock lifters.
11-10-2005, 04:17 PM
#7
One other thing to consider, there is some benefit to the Crane 1.7's as well that would help keep your lifter loads in check. Food for thought if you want to research that approach. You would get a little more valve duration, even though the final lift would be approximately the same.
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11-16-2005, 12:45 PM
#10
Originally Posted by vettenuts
Tony Mamo runs the 1.7's on his car, not sure of the cam but I think it is in the same ballpark as yours, you could shoot him a PM he is very helpful.
Chris (Bone SS) PM'ed me and I thought I would answer this publically to better assist anyone reviwing the thread. While the Crane set-up is my aftermarket rocker system of choice (fairly light for an aftermarket piece and they have a low moment of inertia), the additional heft they do bring to the table does require upgrading the valve spring for additional seat pressure and open load to better control valvefloat which is an extremely weight sensitive issue. The other situation questioned here is rocker ratio which has a profound impact on the "intensity" of the valve events (which would obviously increase with the switch to 1.8 rockers). The cam described above would probably be OK assuming the swap to the stiffer spring, but a safer bet is to run a cam with the additional lift built into it and a 1.7 ratio set-up assuming your plans are to try and spin the engine fairly high (68-7000 RPM's). Some of the smaller cammed stuff with peak lift in the .550's and .560's with short duration work pretty well with the 1.8 swap because that additional rocker ratio adds some area under the curve, the valve event intensity is more manageable, and most importantly, the effective RPM range of a set-up like that is also much lower where valve float typically hasn't come into the picture yet.
To summarize, the 1.8's are a slight gamble on that cam even with the better spring, but without the better spring would, IMHO, have a high likelihood of some loss in valve control at higher RPM's, probably enough to adversly effect power output.
Opinions will vary based on who you speak to, but when I build an engine I prefer to put the lift in the cam lobe and run a more conservative rocker ratio (assuming I can achieve that with the more conservative rocker). However, as I mentioned earlier, the swap to a higher ratio in very conservative smaller cammed apllications can be effective assuming good valve control and heads that will take advantage of the extra airflow.
Hope this helps...
Tony