Drag Strip tips and advice needed.
- Thread starter Kent mosby
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It has been milled .005. Pistons are .010 below deck. 17 cc dish and 78 cc head volume in the trickflow 240s. 4.350 dia, 4.250 stroke. Compressed thickness was .051 of the old ones.
I'm in full agreement with 63GT
you said that the original gasket .050" so that new head gasket will set the head down .023".........your pushrod could become to long now. A push rod change, is well worth getting some quench in that motor.
was this a Hyd Cam or a Mechanical cam?
you said that the original gasket .050" so that new head gasket will set the head down .023".........your pushrod could become to long now. A push rod change, is well worth getting some quench in that motor.
was this a Hyd Cam or a Mechanical cam?
Solid flat tappet cam . 244/252 @ .050”, 282/290 adv, .516”/.537” lift(1.5:1 rocker), 112 sep, .016”/.018” lash. It was made for possible nitrous use later. I have manton 3/8" dia. push rods. I will have to inspect to see if I can use them. I just looked at the wear pattern and saw that they were a bit towards the intake side making me think that they could be ok . Let me know what you think.
I'm not the person to answer that.......but they look fine. Push rod length will not change that.
as lone as you have enough adjuster on the rocker you will be just fine. it only need to be able to go up .023 more then your adj now.
how many threads are showing below the rocker arm adj??
as lone as you have enough adjuster on the rocker you will be just fine. it only need to be able to go up .023 more then your adj now.
how many threads are showing below the rocker arm adj??
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If you can put a .030 head gasket on it. I'd try that.
Might as well try to get some quench in the engine.
Sorry to see the head gasket blowout there.
Might as well try to get some quench in the engine.
Sorry to see the head gasket blowout there.
Well, I fixed the head gasket and got it back to the track for the last drag race of the season, perhaps last races at this track. Our first race, we started out well but during a manual shift my son, the driver, heard something and shut it down. 1.735 60 ft time was decent. The second race he put it in drive and let the transmission do the shifting. He slipped a bit starting but it ran well. He said that it seemed to shift from 1-2 at a lower rpm than needed but we don't know what rpm that was. 12.674 was disappointing but we brought it home without breaking anything this time. Only had one more run that my other son drove and he slipped badly at the start, Not a good burnout to warm them up. In looking at the time slips what is good, bad and what needs improvement?
RockinRobin
Well-Known Member
I would say make sure all of your mechanical issues are fixed first, then:
1. Make sure the chassis is tuned correctly and is getting good weight transfer and it leaves straight and level and not twisted to the drivers side. Without knowing your setup I can't tell you what to change there. I can tell you that you need at least 5" of front end travel or it probably won't hook right. You may have to adjust ride height all the way down to the bump stops in front to make this happen if you still have a torsion bar front end.
hopefully you have adjustable shocks at least on the rear, if not that is a quick swap out. Remember, with a stock leaf spring car the back end will raise up as it leaves the line! You can get mono leaf racing springs but they also require CalTrac bars and that stuff isn't cheap.
Get the front end aligned for drag racing, as much positive camber as you can get and 0 toe in. See if they will let you sit in the car when they do it.
2. Once the chassis is tuned, go to fuel. Check those datalogs for A/F ratio lean or rich spikes or areas.
Get the fuel adjusted to where it runs the same 60', 330, etc. then you can start to experiment with other stuff. Don't try to get your best ET right now, just try to get a consistent ET and the motor isn't too lean. Consistent is more important than fast at this point. Once you've got that, then you can try:
3. Timing advance-give it 2 more degrees and check results. If you have improvement, give it 1 more degree and keep doing this until there is no difference, then back it off 1 degree and call it good.
4. Fuel-since you were already consistent by this point, try adding fuel to lower WOT AFR and see if the car likes it. If it doesn't I would be VERY careful about taking fuel out. If you do, do it VERY gradually and check those datalogs for overly lean. If you have it a little rich you might lose a few hundredths in your ET but it will be more consistent.
5. Shift point- experiment with higher rpm shifts and check for results.
Now the car should be fast AND consistent. Now you have to get the driver consistent:
You need to work on reaction time. If you are racing 1/4 mile you need to get that down below .05 consistently. If 1/8 mile .02 or better. There are many videos on how to accomplish that, they all involve having a lot of seat time.
Assuming you will be bracket racing:
Learn about breaking out and how to avoid it, racing the stripe, getting a good dial in, what to do when the other guy red lights and burnout procedure. Find what works for you. You will also discover that your reaction times might be quicker after dark which will cause you to go red. If that happens there are videos about what to do about that.
Search for American Bracket Racer on youtube. This guy wins a lot and has pretty good procedures on how to bracket race and win. He races a Chevy but his dad races a Mopar.
1. Make sure the chassis is tuned correctly and is getting good weight transfer and it leaves straight and level and not twisted to the drivers side. Without knowing your setup I can't tell you what to change there. I can tell you that you need at least 5" of front end travel or it probably won't hook right. You may have to adjust ride height all the way down to the bump stops in front to make this happen if you still have a torsion bar front end.
hopefully you have adjustable shocks at least on the rear, if not that is a quick swap out. Remember, with a stock leaf spring car the back end will raise up as it leaves the line! You can get mono leaf racing springs but they also require CalTrac bars and that stuff isn't cheap.
Get the front end aligned for drag racing, as much positive camber as you can get and 0 toe in. See if they will let you sit in the car when they do it.
2. Once the chassis is tuned, go to fuel. Check those datalogs for A/F ratio lean or rich spikes or areas.
Get the fuel adjusted to where it runs the same 60', 330, etc. then you can start to experiment with other stuff. Don't try to get your best ET right now, just try to get a consistent ET and the motor isn't too lean. Consistent is more important than fast at this point. Once you've got that, then you can try:
3. Timing advance-give it 2 more degrees and check results. If you have improvement, give it 1 more degree and keep doing this until there is no difference, then back it off 1 degree and call it good.
4. Fuel-since you were already consistent by this point, try adding fuel to lower WOT AFR and see if the car likes it. If it doesn't I would be VERY careful about taking fuel out. If you do, do it VERY gradually and check those datalogs for overly lean. If you have it a little rich you might lose a few hundredths in your ET but it will be more consistent.
5. Shift point- experiment with higher rpm shifts and check for results.
Now the car should be fast AND consistent. Now you have to get the driver consistent:
You need to work on reaction time. If you are racing 1/4 mile you need to get that down below .05 consistently. If 1/8 mile .02 or better. There are many videos on how to accomplish that, they all involve having a lot of seat time.
Assuming you will be bracket racing:
Learn about breaking out and how to avoid it, racing the stripe, getting a good dial in, what to do when the other guy red lights and burnout procedure. Find what works for you. You will also discover that your reaction times might be quicker after dark which will cause you to go red. If that happens there are videos about what to do about that.
Search for American Bracket Racer on youtube. This guy wins a lot and has pretty good procedures on how to bracket race and win. He races a Chevy but his dad races a Mopar.
Thanks, that is a great explanation of what to do. This car has only been together a few months and it is my first “hot rod”. Much to learn, more to do.
ET is chassis. Nice that the 60' has come around.
You are still missing a bunch of MPH IMO... MPH is HP and it's not making what would be expected. Whatever the reason. That's tuning and FI fuel mapping. You picked up MPH from the last time so that is going the right direction.
You are still missing a bunch of MPH IMO... MPH is HP and it's not making what would be expected. Whatever the reason. That's tuning and FI fuel mapping. You picked up MPH from the last time so that is going the right direction.
The initial 1.735 60 ft. Time translated to 535 flywheel hp and 11.3.... 1/4 mile time. 126 mph. Should I expect more?
11.30 is more in the 117-118 range for MPH. 1.73 60' is more in the 12.50 range IMO.
I did notice the camshaft is not very big on lift. Not really taking advantage of the trickflow ports. Engine is probably going to make in the 535-550 hp area on it's best day. It should still run around 11.00 and 118-120 depending on elevation is my guess. 60' in the 1.55-1.60 range would be solid. The trickflow Hyd Roller is 243/247 and .600 lift.
https://static.trickflow.com/global/images/chartsguides/t/tfs-k616-620-576.pdf
TrickFlow.com
Made over 600 hp with 446 inches. The cam you have is giving up a ton of power but would be very streetable. Tune it for what you have.
Headed the right direction.
I did notice the camshaft is not very big on lift. Not really taking advantage of the trickflow ports. Engine is probably going to make in the 535-550 hp area on it's best day. It should still run around 11.00 and 118-120 depending on elevation is my guess. 60' in the 1.55-1.60 range would be solid. The trickflow Hyd Roller is 243/247 and .600 lift.
https://static.trickflow.com/global/images/chartsguides/t/tfs-k616-620-576.pdf
TrickFlow.com
Made over 600 hp with 446 inches. The cam you have is giving up a ton of power but would be very streetable. Tune it for what you have.
Headed the right direction.
Looked here and it says DA was around 3500-4000ft that time of the night
https://airdensityonline.com/track-history/Spokane_County_Raceway/2020-09-18/
https://airdensityonline.com/track-history/Spokane_County_Raceway/2020-09-18/
I’m gonna go ahead and say you don’t need to start throwing money at stuff like Caltracs, springs, adjustable shocks or any other specialized suspension parts for drag racing.............................................yet. Seems that’s what many resort to before optimizing what there is now. For now, learn how to work with what you have. Tire pressure, launches, shift points etc. The idea of throwing stuff at it, replacing this and that makes no sense. Learn with what you have and then have a better understanding of what might need upgrading. Many hook and cook with plain shocks, old springs, maybe a adjustable pinion snubber....but also You seem down on MPH for what you have. Like the brakes are dragging, being held back somewhat. Or fuel/air just isn’t enough....IDK, but one thing at a time always works best
This cam was designed to be prepared for a boost of nitrous. Perhaps that is why it is not very big on lift. Ken from oregon cams said it would also be very streetable. In the rear are SS springs and competition engineering shocks, (CE shocks up front also). Torsion bars are PST 1.03, brand new. The alignment is set for drag racing. It launches straight as an arrow and stops straight, no pulling to one side on either. I will need to do some data logging to see about the AF ratios. I will also check about brake drag, never thought about that. This is the launch video of the first run. Remember that he shut it down 1/2 way through. It seems to hook up pretty well, but with more power maybe it would not. The tires are 255/60-15 mickey thompson ET street s/s tires. 727 goes to an 8 3/4 3.91 ratio rear.
Fat torsion bars are not good for drag set up. Good for cornering.
Getting it to hook well with those bars will be a challenge. That will have little to do with MPH the car should run. That's the ET side of it.
Whatever was done during that launch should be repeated. Burnout, launch rpm, etc... it was the best of the night. Small changes from that is where you want to start with fine tuning launch procedure.
Getting it to hook well with those bars will be a challenge. That will have little to do with MPH the car should run. That's the ET side of it.
Whatever was done during that launch should be repeated. Burnout, launch rpm, etc... it was the best of the night. Small changes from that is where you want to start with fine tuning launch procedure.
I agree do with what you have, up grade laterI’m gonna go ahead and say you don’t need to start throwing money at stuff like Caltracs, springs, adjustable shocks or any other specialized suspension parts for drag racing.............................................yet. Seems that’s what many resort to before optimizing what there is now. For now, learn how to work with what you have. Tire pressure, launches, shift points etc. The idea of throwing stuff at it, replacing this and that makes no sense. Learn with what you have and then have a better understanding of what might need upgrading. Many hook and cook with plain shocks, old springs, maybe a adjustable pinion snubber....but also You seem down on MPH for what you have. Like the brakes are dragging, being held back somewhat. Or fuel/air just isn’t enough....IDK, but one thing at a time always works best
Also RockinRobin post is grate!
Now that i have quoted and said all of that.
The T Bar is way to big for drag racing........street, OK.......
there is vary little front end raise under launch(smaller T Bars would help a lot. PST are to BIG! something under .9xx /6 T-bars would be the best for drag racing and getting that front end to lift.
I'm not saying run out and buy some. Tune with what you got, but if a t-bar come floating by don't pass them up. By them, and put in a corner, and later on switch to them. When you decide to do some front end parts replacing......that's the time to slide them /6 t bars in while your at it. they can collect dust until them.
I say go the other direction... he's going to tnt for fun, not to chop the tree down and go rounds. I wouldn't spend a penny on anything right now.
Get the car to MPH. That's going to be making best HP. Tune what you have and get it sorted out. Where is the timing all in, what are the AF's going down the track, that sort of stuff and make changes to get it to run best.
What tire pressure? I'd run those tires at 20-22 psi. If you are running the same pressure as driving around on the street (30-38), too much. The bugaboo with drag radials is the idea they run pressures like a slick, they don't. They tend to need more pressure, see plenty running 14-18 and that is almost always way too low. The rule here is run the most pressure you can that produces the best 60'. If it 60's 1.50 at 15 and 22 psi, run 22!
Then if you want to get the suspension to 60', start making changes. There is a TON of time locked up in the front end of your car.
Get the car to MPH. That's going to be making best HP. Tune what you have and get it sorted out. Where is the timing all in, what are the AF's going down the track, that sort of stuff and make changes to get it to run best.
What tire pressure? I'd run those tires at 20-22 psi. If you are running the same pressure as driving around on the street (30-38), too much. The bugaboo with drag radials is the idea they run pressures like a slick, they don't. They tend to need more pressure, see plenty running 14-18 and that is almost always way too low. The rule here is run the most pressure you can that produces the best 60'. If it 60's 1.50 at 15 and 22 psi, run 22!
Then if you want to get the suspension to 60', start making changes. There is a TON of time locked up in the front end of your car.
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Thanks guys. The reality of where I live is that we may not have a drag strip next year that is not 6 hours away. Ours is probably going to close. So that car will mostly be just a street car. @crackedback is correct in what my goal is. Get the MPH/hp where is should be first. If we have a track, then I can work on the front end. I knew that the torsion bars were big but I was bottoming out the .850 diameter ones, resting on the bump stops with the adjuster bolt bottomed out so I needed some quickly. I will keep my eyes open for others. The rear tires were at 21 psi, I could never get enough runs to vary the pressure. Also, they hooked at that pressure so no need to go lower. With the efi I will get the tuning done and get the most out of what I have. It will take some time. The comment about brake drag has me pondering, as even a slow trip aroung the neighborhood makes the front discs hot. I will check that later in the week. I cannot get to that today.
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