After rethinking the few runs I tried to get in last year. Other than driver screw up weekend,I know what his dumba$$ did. I had some shake vefore 60'. I had everything set soft planning to make moves one at time after cpl runs. My problem may be too little timing. Running 32* and figure 38( my max or very close.
Now if had blower or 95% in tank I have good idea what it does.NA moyor mot as much.
Question. Anyone tested timing change effect on power with NA motor on dyno. Understand all engines require different combo and many variables. Also more than understand Hemi going to require different than BBC due to chamber design. Just looking for good swag the Scientific part being key word.

My combo for what its worth.
492 ci Hemi
13:1
202 @.050 cam
215 lbs. cranking compression
injected alky
Mag 12 ignition..

Yea nothing like most anyone here. Again not asking what effect will have on mine but rather what you may have found on dyno.

This message has been edited. Last edited by: wideopen231,

I have spent a bunch of time on the dyno and my stuff likes 28*-30* timing. 454 SBC 15 to 1 compression, MSD 7AL-2 ignition. I can run up to 40* timing but it does not make as much power and harder on parts.

I think many people are running too much timing and too fat. When it is fat you can get away with more fuel but it is not optimum. When you get the fuel right you may be able to lean it down more and get more power. Note it is not huge gains but every bit helps.

I have always tuned fuel to where it is slightly past optimal.
Then eased timing up 2* at a time. It it showed leaner I would tweak fuel. If it slowed I know I have made one step too many. Now for headsup stuff like our Top Alcohol cars I kept it right on edge. Needless to say with bracket deal that is not best approach. No real reward why the risk? He11 with TA cars I didn't care if it was slightly past edge if faster. Pistons are just foot soldiers in that case.

If know what percentage of power gained thats kind of what I am looking for. Our rule of thumb was 100 hp per degree with blower stuff or about 3%. I have seen cpl you tube videos where its about 1% per on N A , but they where lower power street stuff.

Are you saying 49 degrees above? Do hemi's like that much more timing than other head styles?

Nope. Do not have second set of eyes on and after few minutes on computer what I am typing is little blurred. I corrected it to 38 it is suppose to read. No auto check on numbers.LOL

What heads are you running, what first gear ratio etc. Are you pulling timing at start? What fuel system are you using? You have a PM.

This message has been edited. Last edited by: TD1964,

What is the overall thought behind using the 1.69 first gear ratio? Is this to reduce the gear ratio at the starting line and thus the torque to reduce wheel speed? I thought we wanted to keep wheel speed up? And.....is it basically the same thing as running less rear end ratio as far as first gear goes?

Heads BAE fuel head. My fuel system with DSR pump at 6.85 gpm system flow just under 3 gpm to motor.Enderle K style BV.

Reason for 1.69. Think about it higher gear gives you more speed. Same as higher rear gear will give you more mph at same engine rpm,because tire is turning higher rpm. Second reason Frank Parks said to and with FED that is almost like word from above. LOL Now if sticking tire at hit I agree that more tq at that point maybe issue. Tire shake is probably biggest balancing act in racing especially. in high horsepower cars.
Think back to when running a 454 or 406 was a big motor. How many bracket racers ever had tire shake? Hell back then we had to explain it to everyone we had raced with before going to TA/FC. Besides if driver does not get out of car with head ache or puking.Have you really had tire shake?

What does the car run?

According to half azz shots I have gotten with it .Car should run 4.70's no problem. According to cpl simulators it should run 4.50's. I don't buy that. Hey some say I have been wrong before. I do not agree and if there is going to be a first might as well be to my good. LMAO wife might not agree with all of above statement.

quote:

Originally posted by wideopen231: ...Besides if driver does not get out of car with head ache or puking.Have you really had tire shake?

I thought I knew what shake was after a couple years running nitrous and getting a few mild headaches. Then I put a blower on and made a huge swing at the tuneup on the last qualifier while outside looking in. I cranked up the boost, leaned it out, turned the 2 step way up and brought all the timing back in at about .5

Car jumped up nose 3’ in the air, rear end about 1’ in the air, then the timing came in right when the rear ended settled. Even though I couldn’t see much of anything I wasn’t going to lift but it didn’t make the shift because the tach and the shifter were both in my lap. I got out of the car on the return road and stumbled around a little and the tech guy that was rolling chutes walked up to me and asked if I was ok. I looked at him for a minute, thought about it real hard, and told him No, not at all. I’ve been in serious car wrecks in street cars and walked away feeling better than that.

I’m sure an alcohol or fuel car would be worse but I’ve never felt anything like that before or since.

Buddy of mine broke an ignition box and steering shaft in half and lost a tooth one time, so I know it can get worse.

Dragster not near as bad as funny car is. Sitting right on top of rear end is just a multiplier. Door car with tire shake I have no experience with so can not comment on.

We ripped a center out of one of three clutch disc in Nebraska and Rickie Bowie(our driver) got out fell to knees and puked from the shake. I learned a lot at expense of his brain cells.

quote:

Originally posted by wideopen231:
According to half azz shots I have gotten with it .Car should run 4.70's no problem. According to cpl simulators it should run 4.50's. I don't buy that. Hey some say I have been wrong before. I do not agree and if there is going to be a first might as well be to my good. LMAO wife might not agree with all of above statement.

Why haven't you been taking it out to the track to run it and get it worked out?

^^^^^^Yes

As soon as the weather allows you need to take it out and make as many runs as you can every weekend and figure out what it wants. Asking and talking about tuning theories isn't going to get it done. Car needs track time and driver needs seat time

quote:

Originally posted by Big Steve:
As soon as the weather allows you need to take it out and make as many runs as you can every weekend and figure out what it wants. Asking and talking about tuning theories isn't going to get it done. Car needs track time and driver needs seat time

Real good point. As an engineer, I like to get my ducks in a row before getting to the track. But sometimes track time is the only thing that gets you the data to fix issues.

quote:

Originally posted by Curly1:

quote:

Originally posted by wideopen231:
According to half azz shots I have gotten with it .Car should run 4.70's no problem. According to cpl simulators it should run 4.50's. I don't buy that. Hey some say I have been wrong before. I do not agree and if there is going to be a first might as well be to my good. LMAO wife might not agree with all of above statement.

Why haven't you been taking it out to the track to run it and get it worked out?

32* and raining every other day do not make for good track days. T-N-T usually menas lots of street crap dragging dirt and rocks onto track and riven by idiots. Bracket race when thaty have them means one test and race. With a not tuned out deal that means maybe two shots. Plus with covid crap we didn't get to hit rack till close to end of season and most where running something besides bracket cars and race car or no dragster allowed.

Had 4 chances to hit rack last year,Made three of those and total of 5 runs.First time I screwed up trans by accidently removing TB delay and hitting it some where and frying reverse clutches out of car, Second I got 1 strong hit and then it got wet. Third I got two runs on track with street junk testing, no track with dirt and air conditioning condensate on starting line. Not to mention driving back down return at 5 mph behind a POS mustang with windows up and taking whole road and cooking the hell out of my stuff even with the richening valve open and fuel coming out pipes from so much alky running thru it.

I might could have gotten two more weekends in before hand but at 95* and high as hell humidity, not me I freaking hate everything when its like that.

There is reason out governor is call Adolph Cooper. Everyting has to stay closed down.

This message has been edited. Last edited by: wideopen231,

Ok guys. Getting away from point of post. Its not about the shake issue. That was just thought path that got me to wondering how much power would hange with it.

Reason? I am always thinking what if or how much and how to track and compare. How can I use this or learn from this and how could it help in future. Was looking for some one who might have been some dyno tuning and made timing change and found a common denominator that gave idea of a rule of thumb. Like I said with the nitro stuff we used degree was about 100 hp per. Tracking change and clutch change according gave idea of what would happen.

The tire shake got me thinking tune was soft and especially on timing. Only reason I mentioned it in post.

So back to our regular programming.

I do not mean to sound rude but nobody here can tell you ANYTHING about your car. Your car is a Front Engine Dragster and they are completely different than other cars. In fact few Front Engine Dragsters are the same from what I can tell. Mine I had to take it our several times and make changes. Most all were an improvement but it took 5 different tire combinations and stiffening the chassis even more to get it where I want it. I also like you raised the chassis up some to help weight transfer and ground clearance.
I have moved a bunch of weight around in addition to stiffening chassis and now my car works. Track time.
When or if I throw more power at it that all goes out the window and I have to start over.

What did I do? I took it to the Track, took video and tried to determine what was going on and how to fix it. Appeared the chassis was flexing too much.

Most of these guys here are running a four link Rear Engine Dragster. They have stiffer chassis and rear suspension to make it work. Ours are hard tails and MUCH more flexible chassis. The key is getting right amount of flex, right tire, right power, right converter and we have much less flexibility than a Four link Rear engine car. So what they are doing has nothing to with what we do. What worked on mine may not work on yours.

If you think more timing would help the ONLY way you or anyone else will know is if you go out and try it.

I also think you learn more RACING than testing. Of course testing helps and has its place but nothing like actual racing to find weak links in your combination.