Coast RPM...kinda long

sst7250 · 01-27-2009, 01:00 AM

I have a question that maybe you guys can help me with. It will proabaly get a little long winded but I an new to this and feel a bit of backround cant hurt so here goes.

I have been trying to run S/ST for the last two years. Due to a few issues I have not been able to make any races at all other than brackets. Last year I was getting close and finally got my combo dialed in ok for a novice I guess. I had a coast RPM of 4800 with my old engine a 572" Hemi. It made max power(840) at 7000 and max torque(750)at 5400 rpm. It seemed to work well and showed good promise, it went 10.90 at 149/150. Well that engine had an unfortunate and catastrophic failure a few weeks before I was planning on my first S/ST race.

Well fast forward to today. I have my new engine(520") in the car and have been getting ready and sorting out the bugs. I always like to get the car sorted out on full power before I slow it down. Just the old heads up racer in me I guess, plus I like to see what the old pig can do. I probably went a bit overboard and now have more than I needed. It makes peak HP(1041)at 7600 and peak torque(776)at 6300.

My engine, while it makes good HP numbers for what it is it has a completely different power band than the old one. On the dyno it was not subjected to RPM lower than 5500 and I can tell you it is a real pig at anything below that, as the wrong converter confirmed for me. So here is my question. What do you experienced guys think would be a good starting point for coast RPM. I think I understand the dynamics of coast RPM but am concerned if I drop it down that low that I will have issues coming off the stop. This new engine really pulls hard from about 6100 and up. My converter stalls at 6300, so I would assume if I come off the stop at 4800 it will immediately flash to 6300 and I could have some tire spin?

I am just looking for experienced opinions on this. I have asked around with some of the local guys I know and am juts seeking others opinions. We plan on trying to get out there this weekend and testing to see what we get, track and weather conditions permitting. HELP A NEWBIE out here guys

01-27-2009, 01:00 AM	#1
sst7250 Member Join Date: Jan 2009 Location: Las Vegas, NV Posts: 184 Likes: 9 Liked 45 Times in 32 Posts	Coast RPM...kinda long I have a question that maybe you guys can help me with. It will proabaly get a little long winded but I an new to this and feel a bit of backround cant hurt so here goes. I have been trying to run S/ST for the last two years. Due to a few issues I have not been able to make any races at all other than brackets. Last year I was getting close and finally got my combo dialed in ok for a novice I guess. I had a coast RPM of 4800 with my old engine a 572" Hemi. It made max power(840) at 7000 and max torque(750)at 5400 rpm. It seemed to work well and showed good promise, it went 10.90 at 149/150. Well that engine had an unfortunate and catastrophic failure a few weeks before I was planning on my first S/ST race. Well fast forward to today. I have my new engine(520") in the car and have been getting ready and sorting out the bugs. I always like to get the car sorted out on full power before I slow it down. Just the old heads up racer in me I guess, plus I like to see what the old pig can do. I probably went a bit overboard and now have more than I needed. It makes peak HP(1041)at 7600 and peak torque(776)at 6300. My engine, while it makes good HP numbers for what it is it has a completely different power band than the old one. On the dyno it was not subjected to RPM lower than 5500 and I can tell you it is a real pig at anything below that, as the wrong converter confirmed for me. So here is my question. What do you experienced guys think would be a good starting point for coast RPM. I think I understand the dynamics of coast RPM but am concerned if I drop it down that low that I will have issues coming off the stop. This new engine really pulls hard from about 6100 and up. My converter stalls at 6300, so I would assume if I come off the stop at 4800 it will immediately flash to 6300 and I could have some tire spin? I am just looking for experienced opinions on this. I have asked around with some of the local guys I know and am juts seeking others opinions. We plan on trying to get out there this weekend and testing to see what we get, track and weather conditions permitting. HELP A NEWBIE out here guys