Lazy off the line - Page 2

bnsfmachinist · 04-13-2016, 10:29 AM

Hans, I'm sure it is brother. I had read somewhere that a C6 will eat about 60-70hp vs. a C4 at 30-40?

This car was originally an F code 302 with a C4, I sold that pair to drop in the New combo. If I could go back I would have kept the C4 and had it prepped for this application rather than going with the C6....but, I'm not terribly concerned at this point. My aim is to bracket race this car and have some fun and learn along the way. Future SS build will of course, NOT include the C6

Mike Pearson · 04-13-2016, 03:17 PM

Not enough rear gear. Carb is too big. Cam needs to be advanced not retarded. That is killing the low end. Fix all of that stuff and it will run much better.

Hans Olsson · 04-14-2016, 10:56 AM

Pressure in the rear tires (10 psi) seems on the low side in my opinion.

cicero819 · 04-16-2016, 07:27 PM

K.I.S.S is the best principal to use in racing, Adger and Keith have great suggestions, I will deviate from KISS and say to Check your converter, could be junk and it's slipping.

voltdr · 04-17-2016, 11:06 AM

Hi. I also believe the heads are too big, especially for the compression ratio. Not enough lower rpm velocity. Since you are just starting out with the idea to be racing for a long time. Buy your self a data logger system. I use Racepak. Most of these issues will show up in a very runs and can actually save you time, money and frustration. I have never seen anyone who finally bought a data logger regret spending the money.
Dan

bnsfmachinist · 04-17-2016, 10:19 PM

Well, just wrapped up a great weekend at Pacific Raceways up here in WA state. Two separate races sat & sun we went down for both. Basically treated the races as a test and tune to see what we could get out of the car given its current running condition.

Improved ET and 60' a little bit by throwing a bit more timing and jetting down.l (it was a bit fat) Car runs pretty consistent though, it is dial-able (still learning the car of course)

Won in round one on Saturday but lost round two. Bummer was that I was comatose on the line. Worst reaction time I've ever put on a time slip. Lost my composure! (First time going beyond the first round of elim's).

Bigger bummer is that my opponent was so far slower on his dial I only needed to cut a .120 light to have won. Kicked my own butt all night after that one!

Sunday went good, found a good spot on the tree, worst RT was a .090 in three passes. Broke WAY out in the first round. I dialed slower, car picked up.

Fun weekend nonetheless.

You boys offering up advice, I hear ya and gonna put 4.56's under it soon. Gonna try a 750HP and see if that helps, looking at a different manifold as well. But other than that I'll just run as is this season. I'll certainly be digging deeper into the situation this winter, gonna look into a more appropriate cam for sure. Maybe a looser converter.

For now, I'll keep absorbing info from folks like you guys and taking it one step at a time.

Sure is fun though, even in the 12's!

blasttime · 08-28-2016, 06:07 PM

Quote:

Originally Posted by Adger Smith

Why is the cam listed as 2 deg retarded with only 10.5 Comp?
Why such a high leave RPM?
Footbrake lower and hit the converter stall harder.
Might be loosing TQ multiplication of the converter.
I would put a little more timing in it before I re jet 2 lower.

X2 on everything

Run to Rund · 08-29-2016, 10:36 AM

I agree with the above advice. When I read the initial post, I felt the carb was too big, the intake too aligned to high rpm (especially depending on how it was ported), and the rear gears too mild. Yes, the carb and intake may match the ported heads, but the overall result is consistent with a high rpm combination, and is being killed by a low rpm combination elsewhere.

Dave Turner · 08-29-2016, 12:53 PM

How much total timing do you have dialed-in....all in by??

pfordamx · 09-27-2016, 12:22 PM

How tall are your rear tires?

3.90s wouldn't be bad if you had 26-27 inch tire i've been mid 1.50s in a 3200lb amx with 4.10s and 28 inch tires with a much milder than your combo 390. that 1.90 sixty foot definitely indicates a issue somewhere.

04-13-2016, 10:29 AM	#11
bnsfmachinist Junior Member Join Date: Feb 2014 Posts: 15 Likes: 0 Liked 0 Times in 0 Posts	Re: Lazy off the line Hans, I'm sure it is brother. I had read somewhere that a C6 will eat about 60-70hp vs. a C4 at 30-40? This car was originally an F code 302 with a C4, I sold that pair to drop in the New combo. If I could go back I would have kept the C4 and had it prepped for this application rather than going with the C6....but, I'm not terribly concerned at this point. My aim is to bracket race this car and have some fun and learn along the way. Future SS build will of course, NOT include the C6

04-13-2016, 03:17 PM	#12
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,444 Likes: 613 Liked 1,916 Times in 574 Posts	Re: Lazy off the line Not enough rear gear. Carb is too big. Cam needs to be advanced not retarded. That is killing the low end. Fix all of that stuff and it will run much better. __________________ Mike Pearson 2485 SS

04-14-2016, 10:56 AM	#13
Hans Olsson Member Join Date: Nov 2001 Location: Sweden Posts: 103 Likes: 0 Liked 0 Times in 0 Posts	Re: Lazy off the line Pressure in the rear tires (10 psi) seems on the low side in my opinion.

04-16-2016, 07:27 PM	#14
cicero819 VIP Member Join Date: Oct 2008 Location: Aylmer Quebec, Canada Posts: 1,086 Likes: 31 Liked 69 Times in 30 Posts	Re: Lazy off the line K.I.S.S is the best principal to use in racing, Adger and Keith have great suggestions, I will deviate from KISS and say to Check your converter, could be junk and it's slipping.

04-17-2016, 11:06 AM	#15
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: Lazy off the line Hi. I also believe the heads are too big, especially for the compression ratio. Not enough lower rpm velocity. Since you are just starting out with the idea to be racing for a long time. Buy your self a data logger system. I use Racepak. Most of these issues will show up in a very runs and can actually save you time, money and frustration. I have never seen anyone who finally bought a data logger regret spending the money. Dan

04-17-2016, 10:19 PM	#16
bnsfmachinist Junior Member Join Date: Feb 2014 Posts: 15 Likes: 0 Liked 0 Times in 0 Posts	Re: Lazy off the line Well, just wrapped up a great weekend at Pacific Raceways up here in WA state. Two separate races sat & sun we went down for both. Basically treated the races as a test and tune to see what we could get out of the car given its current running condition. Improved ET and 60' a little bit by throwing a bit more timing and jetting down.l (it was a bit fat) Car runs pretty consistent though, it is dial-able (still learning the car of course) Won in round one on Saturday but lost round two. Bummer was that I was comatose on the line. Worst reaction time I've ever put on a time slip. Lost my composure! (First time going beyond the first round of elim's). Bigger bummer is that my opponent was so far slower on his dial I only needed to cut a .120 light to have won. Kicked my own butt all night after that one! Sunday went good, found a good spot on the tree, worst RT was a .090 in three passes. Broke WAY out in the first round. I dialed slower, car picked up. Fun weekend nonetheless. You boys offering up advice, I hear ya and gonna put 4.56's under it soon. Gonna try a 750HP and see if that helps, looking at a different manifold as well. But other than that I'll just run as is this season. I'll certainly be digging deeper into the situation this winter, gonna look into a more appropriate cam for sure. Maybe a looser converter. For now, I'll keep absorbing info from folks like you guys and taking it one step at a time. Sure is fun though, even in the 12's! Last edited by bnsfmachinist; 04-17-2016 at 10:22 PM. Reason: Words

08-29-2016, 10:36 AM	#18
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: Lazy off the line I agree with the above advice. When I read the initial post, I felt the carb was too big, the intake too aligned to high rpm (especially depending on how it was ported), and the rear gears too mild. Yes, the carb and intake may match the ported heads, but the overall result is consistent with a high rpm combination, and is being killed by a low rpm combination elsewhere.

08-29-2016, 12:53 PM	#19
Dave Turner VIP Member Join Date: Oct 2005 Location: Schomberg, ON, Canada Posts: 1,222 Likes: 1,606 Liked 364 Times in 138 Posts	Re: Lazy off the line How much total timing do you have dialed-in....all in by?? __________________ Dave Turner SS/GT #1153

09-27-2016, 12:22 PM	#20
pfordamx Member Join Date: Sep 2011 Location: Oklahoma City, OK Posts: 214 Likes: 3 Liked 7 Times in 5 Posts	Re: Lazy off the line How tall are your rear tires? 3.90s wouldn't be bad if you had 26-27 inch tire i've been mid 1.50s in a 3200lb amx with 4.10s and 28 inch tires with a much milder than your combo 390. that 1.90 sixty foot definitely indicates a issue somewhere.