Your exhaust is restricting you. Also a 2.08 valve in a 5.3L head is a TIGHT fit. Must have taken a lot of work to get them in properly.
Chris

 

You think it is my Exhaust Chris? What part of my exhaust? Everyone that looked at the heads said the heads looked great upon initial inspection. Flow Technics work looks awesome. I cant take that away from them. It was just the R&D I had to do for them that was not fair. Also Chris, explain why you think it is my exhaust? Thats easy to change. Many have dyno'd 420rwhp minus cutouts with MAC's. Are you saying my valvesize require my exhaust to be better than MAC's? My timing is also going back to 28 degrees from 26 degrees. My A/F is going to be corrected via pcm and maft initially. I am still going up to Thunder for ls1edit hopefully next month. I am waiting on my friends to be up and running for the 20 hour road trip. Its lonely on the road you know. Anyway, you know my #'s. With my setup my tq should be over 400rwtq.. I am 12rwtq away.. Yes a cutout will get me there, but I want to get as close as possible minus cutout.

<small>[ July 31, 2002, 01:53 PM: Message edited by: VINCE ]</small>

 

Your MACs arent the problem. Your oil soaked catback might be <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I gained just over 1 tenth and over 1.5mph when I switched from a dual outlet muffler to a single outlet dynomax Ultrflo oval race muffler.

I also think you may need tuning. What are the intake cc's of your heads and the exhaust CCs?
Do you have that info?
cheers,
Chris
ps-what compression as well. Your LS6 intake isnt an issue unless it was ported/modified in some way.

 

Chris I am still waiting on the build sheet. So I do not have the exact dimensions on the heads, but Norris Motorsports told me that my compression is 11.3:1 and I am using stock gasket sizes.. So get rid of the dual dual eh.. I like quiet.. Any other quiet exhaust out there that have high flow..? Yes tuning is in the works. I am just waiting on my friends to ride with me..

 

Have you dynotuned on the dyno with LS1Edit?

My ultraflo is really quiet and nice sounding at cruise and sounds really nice at WOT.
Anything else amiss in your exhaust? No bent/dented Ypipe or anything?
Chris

 

My y-pipe has been redone. It is fine. I have not been tuned with ls1edit as of yet. Can you send me a link to your catback system..? Once I open the cutout I will know if the exhaust is the problem. I should see more than the avg 10rwhp increase if my catback is the issue.. Hopefully I can do this next week..

 

Ok.. Anyone have any guesses on my situation..? If this is the case do you think tuning and changing catbacks is really going to pick up 15 to 20rwhp?

 

someone just suggested a hooker catback system..

 

My cranking pressure is 215psi. Most of you know my #'s and they are in the sig if you do not know.. What are other guys getting for cranking pressure? I know I went from the T1 to the 226 XE-R cam, but the logic behind the cam which I was against in the first place says the faster ramps are suppose to make this cam perform similar or better than the T1. I lost 30rwtq at 3500rpm and they became equal by 4100rpm. Posting 380rwtq at that point. I lost 20rwhp at 3krpm and it stays that way until 4000rpm where I am behind 15rwhp compared to the T1. They are not the same still(15rwhp less)until I hit 5k rpm and it is posting 375rwhp with both cams. By 5500rpm I am at 390rwhp with both cams which was my peak with my old cam and headers setup. I hit 400rwhp at 6krpm with the XE-R and I hit 400rwhp with the T1 by 5850rpm. I've been told by several people my 226 XE-R is peaking way to early. It appears to be peaking around 6200rpm. I do not know if the faster ramps are causing this. Most say it is just the heads. Which I could swap if need be. Someone emailed me and mentioned that I need to make sure I have a ls6 intake or make sure nothing is in it.. LOL! I trust my installers. That same someone mentioned that somewhere I am losing some kind of pumping action that is hurting my below 4500rpm #'s. Whether it be cam install, intake, or the #'s I was given on the heads are incorrect. Well I doubt CNC/Norris would would lie about the heads post inspecting them. If anything knowing Norris Motorsports quality and attention to detail they would have immediately offered to sell me some heads because they would not want a poor set of heads associated with their product. There is no question about the cam install. 2 different cams and I have the same peak #'s. I doubt if 2 different people would have installed the cam wrong. The Intake I am positive is a ls6 intake secondary to I looked at it and I see no provisioning for egr. I was also told I could have a bad ls6 intake and mine just sucks. It was suggested I swap ls6 intakes to rule out mine as being a problem. I can do that.. There was another thing that was mentioned.. My exhaust. I have Mac headers with a 3 inch flange going into a 3 inch custom y-pipe going into SLP dual dual exhaust. Now there was a lot of oil in my exhaust post my last engine, but nothing is smoking right now and I am sure it should be all burned out. We will take the exhaust out of the question soon when I open up the dual cutouts in the y-pipe. If I somehow pick up 20rwhp(which I doubt) I will know my exhaust is the problem.

<small>[ July 31, 2002, 01:14 PM: Message edited by: VINCE ]</small>

 

Any other comments..?

 

Vince I am not saying this because I have one but the Hooker is a good flowing, and decently quiet exhaust, ask the guys at Thunder what they recommend when you go. Also the Hooker is cheap so you can't go wrong there.

 

Thanks Mike. I have some more news today.. I went to the track and my car ran slower than my cam and headers setup.. I lost 2 tenths and 2 mph. The weather is the same as it was last summer when I ran my best time with my old setup. The old problem I had when I put the heads on the first time has showed up again. The car is laying down between shifts post 6k rpm. Its funny.. It does not do it all the time.. Just some of the time, but the more I ran her the more it did it. I am thinking I am still having valvetrain issues.. Jason told me awhile ago to change to comp 987's because they should fit in the 1.46 spot I have now. The 987's are 1.43's. What do you guys think?

 

Vince maybe you should just spend the cash <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> and get some new heads, I would hate to see your new forged block take a beating.

 

Vince,
I'm no expert on tuning, but it seems to me that maybe you could be experiencing knock retard. Engine load/cylinder pressure is the greatest immediately after a gear shift. The highest cylinder pressures occur at the peak torque rpm. Can you try some higher octane gas or additive? Please keep us posted.

Good luck,
Richard <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Thanks Richard.. Mike K., dont you have a tkt to work or something..? I am not buying new heads until I change my setup. Whatever it is I will figure this out.. Richard b4 my shortblock went the last time I had the same problem. The weird thing is no scan tool showed any KR at all, but you could be right. I hear no detonation either. Monday I will put some race gas in and see..

 

haha Vince,, que looks good tonight no lie,, the KR theory may be something to consider as it there are no hard shifts being done on the dyno. Man I wish you the best of luck though whatever the case may be, I know this is a stupid question but is it possible that the issue is with your clutch not grabbing like it should?

 

Mike it did it on the last clutch. I have a new one now..

 

Vince,
Regarding your first question, my car is 215 PSI in each cylinder as well. Dynoed at 403 HP and 372 TQ after tuning. I have no new numbers on the track yet. I was supposed to run it today, but I blew the posi up last night. <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" />

 

That is weird derty that you would have the same cranking pressure and dyno the same as me. My tq is just higher.. What tuning do you have. My tuning is way off and I am getting ls1edit to correct it..