Worth the cam change?
03-04-2014, 12:04 PM
#21
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Is surge only in lower gears like 1st and 2nd or does it happen on the highway too? My rpms are usually at 1700 in 6th
03-04-2014, 12:34 PM
#22
Thanks for all the responses guys! My 224 228 cam is from Texas Speed and DYNO on cam and bolt ons only was 392rwhp and 375 ft lbstq. My cam has huge low-mid range but feels like the power starts falling of between 5500-6500 rpms. I think the sinister cam has a 1800-6800 rpm range, idk what my 224 228 rpm range is but I just want the power to not thin out at the end with the cam.
03-04-2014, 12:36 PM
#23
Yo might feel it a little bit in 6th at that RPM, nothing to bad. I have to agree with the people saying more compression and do the cam swap.
That came will not be THAT bad in driveablity, if you can get the tune right it will idle fine and drive just fine. It will drive even better if he was to gear it properly. You could probably leave it but I would think a 3.73 would be great, or be a baller and go with 4.11
My cam idles like a ******* Prostocker and drove like **** in 1st gear and low RPMs, then I geared it and it drives pretty close to stock considering it has nearly 70 degrees of overlap if my math can be trusted.
FWIW if you want to swap to the 11/32 pushrods like Bozz said, call one of the places that does custom push rods. Get one that tapers at the ends, it will save you a little bit of weight but still give you the deflection resilience you need in the middle of the rod. You always have to think about saving weight if running those Xtreme Energy lobes.
That came will not be THAT bad in driveablity, if you can get the tune right it will idle fine and drive just fine. It will drive even better if he was to gear it properly. You could probably leave it but I would think a 3.73 would be great, or be a baller and go with 4.11
My cam idles like a ******* Prostocker and drove like **** in 1st gear and low RPMs, then I geared it and it drives pretty close to stock considering it has nearly 70 degrees of overlap if my math can be trusted.
FWIW if you want to swap to the 11/32 pushrods like Bozz said, call one of the places that does custom push rods. Get one that tapers at the ends, it will save you a little bit of weight but still give you the deflection resilience you need in the middle of the rod. You always have to think about saving weight if running those Xtreme Energy lobes.
03-04-2014, 12:47 PM
#24
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Ok, I already have the 373 gears and my guy that tunes my car is really good. I know Hawk's Sinister 230/236 says the rpm range is 1800-6800 but is that actual rpm range or ballpark? How can you tell?
03-04-2014, 01:01 PM
#25
Manton makes 11/32 pushrods that fit cathedral heads with no extra clearancing needed. You can buy them from Hinson.
Trend makes 3/8" pushrods with double taper that have been proven to fit cathedral heads as well, but it's a tight fit, so it has to be verified.
You can determine RPM range by the intake valve closing event and how early the exhaust valve opens.
That 230/236 cam is a nice profile. Will peak in the mid 6000s and carry to 7k rpm if you want to spin it that high.
Trend makes 3/8" pushrods with double taper that have been proven to fit cathedral heads as well, but it's a tight fit, so it has to be verified.
You can determine RPM range by the intake valve closing event and how early the exhaust valve opens.
That 230/236 cam is a nice profile. Will peak in the mid 6000s and carry to 7k rpm if you want to spin it that high.
03-04-2014, 01:14 PM
#26
So at 1700 RPM in 6th gear, the throttle will be open enough not to feel any surge with a 9* overlap cam. With my 10* overlap cam, if I just slightly opened the throttle at 1500 rpm in 4th gear (30 mph) the surging stopped.
Russ Kemp
03-04-2014, 01:16 PM
#27
As I mentioned, the surge is at low rpm/light throttle. That's due to the higher intake manifold vacuum that pulls the exhaust back into the cylinder as the intake valve is starting to open and the exhaust valve is still not closed in the overlap position. So when you open the throttle further (like when the engine is under more load) the intake vacuum is reduced, thus pulling less exhaust back into the cylinder.
So at 1700 RPM in 6th gear, the throttle will be open enough not to feel any surge with a 9* overlap cam. With my 10* overlap cam, if I just slightly opened the throttle at 1500 rpm in 4th gear (30 mph) the surging stopped.
Russ Kemp
So at 1700 RPM in 6th gear, the throttle will be open enough not to feel any surge with a 9* overlap cam. With my 10* overlap cam, if I just slightly opened the throttle at 1500 rpm in 4th gear (30 mph) the surging stopped.
Russ Kemp
03-04-2014, 06:57 PM
#29
Changing my cam with a wider LSA fixed all my drive- ability issues. Then some people keep the trans in a lower gear & cruise around at 2000+ RPM and say their car drives like stock?
I have a customer with a 2004 ZO6 with ported heads 2.02/1.60 valves, 62 cc .052 gasket (11.0 CR), 1.75 American Racing headers, catted midpipe, LPE GT 11 215/231 118 lsa cam.
He wants more mid range to top end power and refuses to have any surge at low rpm/light throttle. So I recommended a 228/240/117+4 .600/.600 cam. Should be installing it in the next couple of months. Also I will be retuning the PCM with my Hp Tuner & FJO wideband.
Russ Kemp
03-04-2014, 07:55 PM
#30
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Sorry to go a little off subject but im taking yalls advice about the fast manifold for my setup and am looking at a fast 92 with nick william's 92 tb and im reading I cant use the stock ls1 fuel rails. I was looking on ws6store.com and found a few brands including fast but I have no idea about return/returnless or any of that suff. Can anyone tell me which kit/part number of a kit that I need for my car? I see a kit that looks the same as the fast but its called "power"? Does anyone know if it is the same or as good as fast?
http://www.ws6project.com/user_stor/catalog/fuel-rails/
http://www.ws6project.com/user_stor/catalog/fuel-rails/
03-04-2014, 08:36 PM
#32
ls1 rails bolt right up to a fast 90 or 92 intake. They do not bolt up to the fast 102, perhaps that is what you saw. For a 102, you can use an ls2 rail, but you need different height injectors or you gotta space the rail out.
03-04-2014, 08:51 PM
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Oh ok, yeah I must have been reading about the 102mm. Im using 42lbs injectors and I assume the stock ls1 rails hold alot more power than ill ever make
03-07-2014, 12:07 PM
#37
Improving the efficiency of the engines breathing ability with a better intake or larger set of headers will help to make more power at higher rpms without even changing the cam. The cams valve events will help determine the power band, just keep in mind a later IVC not only shifts the power band higher it lessens the theoretical stroke of the engine by trapping the intake charge later therefore compressing it less and making less torque through less dynamic compression. That's why a compression bump is generally recommended to keep from having any torque loss. Now you can tailor a cam to have the same IVC and a more efficient exhausting of the chamber if you will, with a larger exhaust lobe that will help the power not drop off after peak with more overlap though that can sacrifice some of the driveability. That will improve it's higher rpm efficiency without sacrificing torque, the general rule of thumb is 2hp for every 1* increase in duration. There is usually always a trade off with a bigger cam, unless other complimenting changes are made...hope that helps, Chris
