soft loc or advanced launch question

L79racer · 11-06-2007, 10:28 PM

I would like to know how much if any, rpm drop you guys get on the launch. I am running a ram adjustable clutch 1800 to 2400 base. No counter weights. Its set at 1800 and when launching at 5000 the motor still pulls down when it dead hooks. I am thinking of going with a fully adjustable plate over this winter. Took the vega to the track this week. best run was 10.44 @ 133 with a 1.52 60 foot I know thats a ****ty short time. Should be in the high 1.30's. I do drive this on the street so that is why I didnt get the fully adjustable in the first place. Car is just over 2800 lbs with me in it. 4.56 rear and 2.64 fist gear. I am curious to how much base pressure you guys run at that weight. I am not ready to buy a new plate so I dont want to call Rob or Ram and waste their time until I am ready to buy it. Just looking for so info untill I'm ready.

castle5 · 11-06-2007, 10:51 PM

has to do with balance of gear ratio,s and clutch set up. if your looking for streetability you will always have problems. if your looking for a race setup, you will need more 1st gear and an adjustable clutch. to get better 60 ft times...of course everyones combination takes time to sort out....

Bill Unruh · 11-06-2007, 11:43 PM

I'm still sorting mine out, it's one of Robs clutchs.
appox 3380# , leave @ 6K, 1100# base pressure, I'm running the counter weight he shipped it with.
Total 1st gear is 11.38, 28.5" tire.
I used my EFI data loger one time. That pass it pulled down to 4950rpm, that was with old tires, 1.47 60'.
Made one pass with new tires last week. I added 1/4 turn base pressure, thinking more bite would need a little more clutch, It worked, went 1.38 60', but the data loger failed.

Here's the video maybe you can hear how much it's pulling down? about 1000rpm? 6K on the two step.

---Bill.

Jeff Lee · 11-07-2007, 02:46 AM

133 should be deep into the 9's. Deep in the 9's should be 1.30's on the 60'. If somebody told me I could pick up over a half-a-second in the quarter and I would have a 9 second street car, the last thing you would hear me say would be "I am thinking of going with a fully adjustable plate over this winter." Personally, I would have my VISA or cash to Rob as soon as I got done typing that post. Look at it again, you've layed out your problems and it looks like you know what the answers are. Am I right? I don't think 1800#'s of base pressure could ever work in that light of a car. Sorry, I just don't see any way around it! Well maybe if you launched at 9500 RPM and pumped up the slicks a bunch and tightened up the front shocks...really don't think you want to go there, do you?
Think about this. You've got a SBC that runs 133. Sure it's a light car but still 2800 pounds @ 133 equals somewhere around 525 HP. How much did that cost to obtain?
So what's another $2100?
With a friend turning over the engine with a wrench, you can make all the adjustments from street to track that the clutch needs in less than 15 minutes. And that should take into account jacking up the car.
Cha Chang!
9's....

L79racer · 11-07-2007, 08:38 PM

Thanks for responding guys. Bill your camaro looks great. Jeff, you are right on everything you posted. Only problem is I dont want to put $2100 on my credit card. So, I'll have to save some extra cash and when I have enought I'll get the clutch that is needed. I do want to get it into the 9's. I was under the assumption that the rpms would barelly drop on a launch with a fully adjustable clutch. So, I guess you guys dont even feel the clutch slipping on the launch. You still get the feeling of a truck running into the back of the car? I'll keep you guys updated as it progresses. Jeff , if you still have the videos of your amx please post them. I'de like t see it leaving. Anybody else like to post some videos it would be great to watch.

Jeff Lee · 11-08-2007, 12:09 AM

I haven't run my Advanced Clutches dual disk yet. It will be part of the "winter makeover" which will probably translate into spring. But on my Advance Clutches single disk, I do not have that "dump truck just rear-ended me" syndrom. And yes, I know what your talking about! I guess if your looking for a description it's more like that roller coaster sensation when youare at the bottom of a fast drop and theh you suddenly are accelerating up and forward on the next rise. When the clutch is rightly adjusted you won't have that "bam!" in your back and you won't feel it drop in RPM, though you can see it on the tach if your watching. And to tell you the truth, I haven't used my Autometer playback tach in years so I can't tell you a firm number that the RPM drops. It's somewhere between 600-800 RPM. I just keep loosening the clutch and looking at the ET ticket. I'm at the point I rely on Advanced Clutches to set the counterweight correctly so I don't even worry about that department anymore. I am installing an Autometer Ultimate II with driveshaft RPM readout. I probably won't be able to desipher the data though. I have an aversion to high electrical tech. That's why I don't have a data recorder. But then again, I'm also installing a dual O2 sensor from FAST. Oh geez, what the heck am I getting into!!!

You asked about base pressures. My single disk was a 300# minimum, last time out I had around 2.5 turns into it for a total of 600# (base + adjustments). But you have to keep in mind you can't really compare notes from one car to the other. Launch RPM, shift RPM, HP, car weight, gearing, etc., will all make differences to base pressure and CW.
Another note. You might talk to Rob about making refinements to your RAM. I don't know the cost and I think it will probably vary by what is needed. So if your on a budget, that may help.
Lastly, I run a 97" wheelbase in my AMX. So does Rob. Just as your Vega. I would suggest you'll seriously consider the purchase of some wheelie bars before you change clutches. Seriously

Here's my AMX on YouTube. You can see why it's in the chassis shop. The floorboards have been pounded in (towards the interior) and the car won't sit square anymore. That's why it keeps going left. But it makes it more fun to watch I suppose...
Note were the 60' bulbs are at...

Joe Sprint Bros · 11-08-2007, 11:36 AM

L79, I've been there with the progression from Ram to Adv, and have some inexpensive ideas that may help,also have some questions. Joe Helms info@sprintbros.com , or (434)841-7349.

Dave Casey · 11-08-2007, 04:55 PM

Looking at your info, the most glaring issue I see is that you need more 1st gear. That will make big changes to your car. You can go very fast with your ram stuff. The soft lock/advanced stuff is also great stuff, but my first choice would be a 3.0-3.1 first gear.

If that is not possible, how about 4.88 or 5.13. I say that because you are on a budget and I understand that.

3 years ago I went -135 under with my stocker with a 6 pad ram and no counterweight, so you can do real good with what you have.

Dave

Jeff Lee · 11-08-2007, 06:21 PM

Gearing would no doubt help. Remember, this is a dual purpose car so gearing for optimum ET may not be a consideration. But the car presently goes 133 MPH which really should produce an ET of around 9.80, not 10.45. I can see the clutch work getting it down there but not even close with gearing. Getting an 1800# PP to work on a stocker that is probably on a 20% to 25% heavier vehicle which most likely has optimal gearing must also be taken in consideration when making comparisons.
My guess is 5000 RPM launches are employed as that is all it will take as far as traction goes. Right L79? If so, that's because there is too much clutch. If it will take a higher launch then by all means give it a whirl.

L79racer · 11-09-2007, 08:59 PM

Joe, I'm going to send you an email.

Jeff, I ran the car twice leaving at 4000 because it was the first time to the track with a 4 link that I put in myself. I didnt really know how the car would react so I thought I should take it easy fot the first couple of passes. I had a set of 28x11.5 M/T slicks on the car. both passes were 10.50 at 132.After the two passes I noticed the were growing more than I thought and were starting to rub the front of the quarter panels. So, I switched to a set of 28x10 Hoosier slicks which are actually about an inch shorter than the M/T's. With the hoosiers I left at 5000 but they spun a little and werent lifting the wheels off the ground. The car ran the same 60' but went 10.44 at 133. I tried lowering the air but I think the hoosiers compound is too soft for a stick car. I posted a video so you can see how the car left with the 28x11.5 M/T slicks. Check out the light I cut, not bad for a amateur.
Mustang has a 427 small block ford in it. I hope the link works!!

http://www.metacafe.com/watch/910263/vega_vs_mustang/

11-06-2007, 10:28 PM	#1
L79racer Member Join Date: Jan 2005 Location: North Massapequa, NY Posts: 218 Likes: 0 Liked 0 Times in 0 Posts	soft loc or advanced launch question I would like to know how much if any, rpm drop you guys get on the launch. I am running a ram adjustable clutch 1800 to 2400 base. No counter weights. Its set at 1800 and when launching at 5000 the motor still pulls down when it dead hooks. I am thinking of going with a fully adjustable plate over this winter. Took the vega to the track this week. best run was 10.44 @ 133 with a 1.52 60 foot I know thats a ***ty short time. Should be in the high 1.30's. I do drive this on the street so that is why I didnt get the fully adjustable in the first place. Car is just over 2800 lbs with me in it. 4.56 rear and 2.64 fist gear. I am curious to how much base pressure you guys run at that weight. I am not ready to buy a new plate so I dont want to call Rob or Ram and waste their time until I am ready to buy it. Just looking for so info untill I'm ready. Last edited by L79racer; 11-06-2007 at 10:35 PM.*

11-06-2007, 10:51 PM	#2
castle5 Junior Member Join Date: Nov 2005 Location: indiana Posts: 39 Likes: 0 Liked 0 Times in 0 Posts	Re: soft loc or advanced launch question has to do with balance of gear ratio,s and clutch set up. if your looking for streetability you will always have problems. if your looking for a race setup, you will need more 1st gear and an adjustable clutch. to get better 60 ft times...of course everyones combination takes time to sort out....

11-06-2007, 11:43 PM	#3
Bill Unruh Junior Member Join Date: Feb 2007 Location: Riverside California Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: soft loc or advanced launch question I'm still sorting mine out, it's one of Robs clutchs. appox 3380# , leave @ 6K, 1100# base pressure, I'm running the counter weight he shipped it with. Total 1st gear is 11.38, 28.5" tire. I used my EFI data loger one time. That pass it pulled down to 4950rpm, that was with old tires, 1.47 60'. Made one pass with new tires last week. I added 1/4 turn base pressure, thinking more bite would need a little more clutch, It worked, went 1.38 60', but the data loger failed. Here's the video maybe you can hear how much it's pulling down? about 1000rpm? 6K on the two step. ---Bill. Last edited by Bill Unruh; 11-16-2007 at 12:53 PM.

11-07-2007, 02:46 AM	#4
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 2 Times in 2 Posts	Re: soft loc or advanced launch question 133 should be deep into the 9's. Deep in the 9's should be 1.30's on the 60'. If somebody told me I could pick up over a half-a-second in the quarter and I would have a 9 second street car, the last thing you would hear me say would be "I am thinking of going with a fully adjustable plate over this winter." Personally, I would have my VISA or cash to Rob as soon as I got done typing that post. Look at it again, you've layed out your problems and it looks like you know what the answers are. Am I right? I don't think 1800#'s of base pressure could ever work in that light of a car. Sorry, I just don't see any way around it! Well maybe if you launched at 9500 RPM and pumped up the slicks a bunch and tightened up the front shocks...really don't think you want to go there, do you? Think about this. You've got a SBC that runs 133. Sure it's a light car but still 2800 pounds @ 133 equals somewhere around 525 HP. How much did that cost to obtain? So what's another $2100? With a friend turning over the engine with a wrench, you can make all the adjustments from street to track that the clutch needs in less than 15 minutes. And that should take into account jacking up the car. Cha Chang! 9's.... __________________ Jeff Lee 7494 D/S '70 AMX

11-07-2007, 08:38 PM	#5
L79racer Member Join Date: Jan 2005 Location: North Massapequa, NY Posts: 218 Likes: 0 Liked 0 Times in 0 Posts	Re: soft loc or advanced launch question Thanks for responding guys. Bill your camaro looks great. Jeff, you are right on everything you posted. Only problem is I dont want to put $2100 on my credit card. So, I'll have to save some extra cash and when I have enought I'll get the clutch that is needed. I do want to get it into the 9's. I was under the assumption that the rpms would barelly drop on a launch with a fully adjustable clutch. So, I guess you guys dont even feel the clutch slipping on the launch. You still get the feeling of a truck running into the back of the car? I'll keep you guys updated as it progresses. Jeff , if you still have the videos of your amx please post them. I'de like t see it leaving. Anybody else like to post some videos it would be great to watch. Last edited by L79racer; 11-07-2007 at 08:42 PM.

11-08-2007, 12:09 AM	#6
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 2 Times in 2 Posts	Re: soft loc or advanced launch question I haven't run my Advanced Clutches dual disk yet. It will be part of the "winter makeover" which will probably translate into spring. But on my Advance Clutches single disk, I do not have that "dump truck just rear-ended me" syndrom. And yes, I know what your talking about! I guess if your looking for a description it's more like that roller coaster sensation when youare at the bottom of a fast drop and theh you suddenly are accelerating up and forward on the next rise. When the clutch is rightly adjusted you won't have that "bam!" in your back and you won't feel it drop in RPM, though you can see it on the tach if your watching. And to tell you the truth, I haven't used my Autometer playback tach in years so I can't tell you a firm number that the RPM drops. It's somewhere between 600-800 RPM. I just keep loosening the clutch and looking at the ET ticket. I'm at the point I rely on Advanced Clutches to set the counterweight correctly so I don't even worry about that department anymore. I am installing an Autometer Ultimate II with driveshaft RPM readout. I probably won't be able to desipher the data though. I have an aversion to high electrical tech. That's why I don't have a data recorder. But then again, I'm also installing a dual O2 sensor from FAST. Oh geez, what the heck am I getting into!!! You asked about base pressures. My single disk was a 300# minimum, last time out I had around 2.5 turns into it for a total of 600# (base + adjustments). But you have to keep in mind you can't really compare notes from one car to the other. Launch RPM, shift RPM, HP, car weight, gearing, etc., will all make differences to base pressure and CW. Another note. You might talk to Rob about making refinements to your RAM. I don't know the cost and I think it will probably vary by what is needed. So if your on a budget, that may help. Lastly, I run a 97" wheelbase in my AMX. So does Rob. Just as your Vega. I would suggest you'll seriously consider the purchase of some wheelie bars before you change clutches. Seriously Here's my AMX on YouTube. You can see why it's in the chassis shop. The floorboards have been pounded in (towards the interior) and the car won't sit square anymore. That's why it keeps going left. But it makes it more fun to watch I suppose... Note were the 60' bulbs are at... __________________ Jeff Lee 7494 D/S '70 AMX Last edited by Jeff Lee; 11-08-2007 at 12:11 AM.

11-08-2007, 11:36 AM	#7
Joe Sprint Bros Junior Member Join Date: Nov 2004 Location: Virginia, USA Posts: 46 Likes: 0 Liked 0 Times in 0 Posts	Re: soft loc or advanced launch question L79, I've been there with the progression from Ram to Adv, and have some inexpensive ideas that may help,also have some questions. Joe Helms info@sprintbros.com , or (434)841-7349.

11-08-2007, 04:55 PM	#8
Dave Casey VIP Member Join Date: Dec 2002 Location: Hampden, MA Posts: 1,171 Likes: 216 Liked 674 Times in 143 Posts	Re: soft loc or advanced launch question Looking at your info, the most glaring issue I see is that you need more 1st gear. That will make big changes to your car. You can go very fast with your ram stuff. The soft lock/advanced stuff is also great stuff, but my first choice would be a 3.0-3.1 first gear. If that is not possible, how about 4.88 or 5.13. I say that because you are on a budget and I understand that. 3 years ago I went -135 under with my stocker with a 6 pad ram and no counterweight, so you can do real good with what you have. Dave __________________ Dave Casey 1330 STK

11-08-2007, 06:21 PM	#9
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 2 Times in 2 Posts	Re: soft loc or advanced launch question Gearing would no doubt help. Remember, this is a dual purpose car so gearing for optimum ET may not be a consideration. But the car presently goes 133 MPH which really should produce an ET of around 9.80, not 10.45. I can see the clutch work getting it down there but not even close with gearing. Getting an 1800# PP to work on a stocker that is probably on a 20% to 25% heavier vehicle which most likely has optimal gearing must also be taken in consideration when making comparisons. My guess is 5000 RPM launches are employed as that is all it will take as far as traction goes. Right L79? If so, that's because there is too much clutch. If it will take a higher launch then by all means give it a whirl. __________________ Jeff Lee 7494 D/S '70 AMX

11-09-2007, 08:59 PM	#10
L79racer Member Join Date: Jan 2005 Location: North Massapequa, NY Posts: 218 Likes: 0 Liked 0 Times in 0 Posts	Re: soft loc or advanced launch question Joe, I'm going to send you an email. Jeff, I ran the car twice leaving at 4000 because it was the first time to the track with a 4 link that I put in myself. I didnt really know how the car would react so I thought I should take it easy fot the first couple of passes. I had a set of 28x11.5 M/T slicks on the car. both passes were 10.50 at 132.After the two passes I noticed the were growing more than I thought and were starting to rub the front of the quarter panels. So, I switched to a set of 28x10 Hoosier slicks which are actually about an inch shorter than the M/T's. With the hoosiers I left at 5000 but they spun a little and werent lifting the wheels off the ground. The car ran the same 60' but went 10.44 at 133. I tried lowering the air but I think the hoosiers compound is too soft for a stick car. I posted a video so you can see how the car left with the 28x11.5 M/T slicks. Check out the light I cut, not bad for a amateur. Mustang has a 427 small block ford in it. I hope the link works!! http://www.metacafe.com/watch/910263/vega_vs_mustang/