delbuort

I'm planning on getting the LT4 Hotcam and I was wonder if you guys that have it already could tell me if I should go with the 1.5 or 1.6 RR? What would the differance be in performance? Advantages and disadvantages please?

Thanks ahead of time for the input,
Jason

stevil

1.6RR, so you get even more lift. More lift = more power. 1.5 is stock ratio, I suppose you could use the stock rockers if you wanted to save some money or something... Almost everyone upgrades to 1.6RR when they do a cam.

Just for comparison, with stock cam and an upgrade to 1.6RR I gained 12 rwhp.

delbuort

I like the more power thing. I knew that the 1.6 gave more lift but I wasn't sure how much of a differance the 1.6's would make over the 1.5's. Just replacing the stock rockers with the 1.6's and gaining 12hp is a pretty good deal.

Has anyone tried 1.7 or higher with the Hotcam? What kind of gains did you have?

EvlViln

Hot cam springs ar only good for about .550 lift, beyond that you run into coil bind. with 1.7 you run into a .558 lift.

Can it be done. Yes.
Should it be done. up to you. I would say no.
I have seen guys run 1.7's and it work for them. But it is easier on the valve train (speaking interms of longevity) to have a high lift cam & 1.5's rather than a low lift cam and 1.7's.

Just my opinion, I could be wrong.

Compstall

I talked to a guy that saw nearly no gain at all between a full roller 1.5 rocker over a 1.6. That leads me to believe that you're gaining the power more from less frictional losses through the roller-type valvetrain over the stamped rockers.

- Brent

delbuort

Can any of you guys suggest a nice cam that has a higher lift that I could use with those lower lift rockers? I'm looking for something that is still very streetable (i.e.-the Hotcam). I want some good power gains without compromising a daily driver.

Jason

Dave Feerst

The reason most people dont gain much from just switching to 1.6 rockers is the stock heads, Believe it or not the intake of my bone stock heads at 10 inches of water column flowed 115CFM at .450 lift which is about stock valve lift and 113CFM from .500 all the way through .600. No more airflow means no more horsepower and a loss of torqure due to air velocity, However on the ramps of the cam lobe the lift increase can cause more airflow. And on the exhaust side my heads were still increasing airflow up till .550 lift with stock heads. So that would lead me to believe almost all gains from the 1.6 would be from the exhaust side and the gains might acually be better with the 1.6 on the exhaust side only (with stock heads that is). gonna try it one of these days.
Regardless, 1.7s on stock heads are useless and dangerous.... Switching from a stamped 1.6 to roller 1.6 ive seen gains of 2-3 HP so frictional loss does play a small part but I wouldnt say its the majority of the change.

Cmr0z28

just get the LT4 hotcam kit and save urself the money, it comes with 1. 6 rockers and all the other crap

yorkie

just use the 1.5 rockers unless you go with the kit with 1.6's The gains are soooo minimal, just put ice on the intake and get more hp then the 1.6's Ha Ha

stevil

Minimal gains? Can you just pull 10-15 rwhp out of your *** or what? I have before and after dyno results, could you please post your "bag of ice" dyno sheets?

Bottom line, 1.6 rockers add .030" of lift on a stock cam over 1.5, and .033" more with the LT4 Hot Cam. Part of the reason for switching to a bigger cam is, get this... more lift!

Jason, check out this page:

http://www.fierolt1.com/lt1_camdata.htm

It shows what the cams lift will end up doing with what rocker ratio (1.5 & 1.6). They make some cams that have more lift, but check the duration... I'd just get the Hot Cam kit and be done with it, should have cam, springs, rockers, etc.

Blue96z28

couple questions..what is the honest RWHP gain in a stock car like mine(see sig)...also can the 1.6 in the kit be used w/the stock valve covers.....?
one more(sorry) how street able is the lt4 hot cam kit?, anyone know affects on gas mlg or computer...does it require tuning or a chip?
thanks ahead of time you your input

Dave Feerst

the kit is very nice. It is mostly top end gain which makes it great for the track. From the people I've talked to 1-2 MPG loss and the best improvement i saw was a 94 Intake / shortie headers / catback / BBK 52mm TB he ran mid 13s without the cam and with just the cam (kit) swap ran 12.78 at 108 (US 41 dragway on a less than good day for racing. through stock heads and everything. The car till sounded stock at Idle too. but I dont think it would pass an IM240

redkillerz

I just completed a complete overhaul of my 95 z28 and I installed the hot cam kit with 1.6rr and it sounds great Idles with a good lope, I did a port and polish on my heads though, I gained .45 in the 1/8 mile this past thursday running consistant 8.8's in the 1/8th had one 8.7. I put down a mustang 5.0 with nitrous and a cammed up 2000 ss ls1 with programming and long tubes that night as well, I can't wait to see how much better it will do with programming, it made a difference for me, the rr in the kit will fit under the stock valve covers as well no interference did not have to modify them at all hope this helps you decide.

delbuort

stevil,

Nice page. Thanks for the info guys. I think you've all talked me into just getting the Hotcam kit and leaving well enough alone.

Right now I'm looking at staying as cheap as possible. I've found the entire kit at www.samtaylor.com/html/parts.html for $465, but I was wondering if I could get it cheaper piece-by-piece? I've found the springs, retainer, shims, and keys for about $60 and the Hotcam for $185 (shipped) from http://www.sdpc2000.com/cart.asp?act...tart&catid=540 And, a set of rockers at Jeg's, http://www.jegs.com/cgi-bin/ncommerc...59&prmenbr=361 part number 778-66915C for $189. So, it all comes to about $30 less than buying the kit togeter and I don't have to money at this moment to spend on the entire kit. I was think of buying it a little bit at a time and work my way up to it. My question is...has anyone used these rockers before and are they a suitable replacement for the ones that come in the kit? Sorry for the long post. And again, thanks for the info.

Jason

yorkie

roller rockers, I went with just the cam and 1.5 stock rokers, gives you .492 lift, gmpartsdirect.com has the cam for 185.00 delivered too. Anything over .495 requires the factory 85 pond springs to be changed, if you use the hotcam and the 1.5 rockers, no spring upgrade needed.

Eric