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Discussion Starter #21
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When trying to fine tune, you need to be at least close.
When I 1st make a big change, like engine, trans, converter I don't freak out about wild swings.

I'm saying when my car was dialed in, chassis & engine, then I would get a little more MPH when I had a bad 60'.
Until it's close, you could be chasing 7 different issues simultaneously!!!

Good luck.

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Thank you. Yeah I think with more seat time I’ll improve a ton. The numbers threw me off. But the car is going faster and that’s a step in the right direction.
Checked the D/A for my run and it’s showing like 2400 ft above sea level. My runs last year I want to say it was negative a few hundred feet. I think after doing a little more reading there were too many variables to compare this year to last years.
 

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Discussion Starter #22
Bump the launch RPM up 300-500ish and see what it does. 1.7 60s is really 12 second territory, you are leaving a lot on the table in the first 100' of track.
Last year the 1.7 was all it had. Trans brake no two step. Tried lowering it to try to “flash” the converter on launch. It just didn’t get better.
This year I do think I’ll be low 1.5s. If not slightly dipping into the 1.4 range.
 

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As DA increases you must compensate with more boost. Lets say you raced over the weekend in +3000 DA from your previous times. You would need roughly 1.5 psi more boost to maintain the same power.

Seems like it is all good to me. When you compensated with more boost it got you right back on track with mph. Your new setup is likely running slightly different and/or no wind at your back or it was in your face. Those small details can easily account for your mph difference.
 

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The 10.96 run was from last year. The 10.87 run was from this year. Even at the 330 it was .3 quicker this year. Unless I’m misunderstanding what you are saying.
And targets were pretty close on the runs. My 1st run had like 2-3 % closed loop correction in some spots. 2nd run was 1-2%.

As far as the reaction time. Just feeling the car out. Once I figure out staging and launching under boost I’ll know how much time I need leading up until that. I swear I’ve cut a halfway decent light before. Lol
Here's a way to look at your time slip to understand what your changes do. Splits tell you what part of the track your car is working and where it isn't.
Your car is working to 330 feet and then loses steam (except for the +2psi run)

Back end mph gain is pure power level - even after adding boost you're still down a tad.
If last year's time slip was a hero run, leave it out of the mix and grab a time slip that is representative of its average performance.
Lastly, what is it with covering up date and time details on time slips?! From the date, time and place I can calculate ETs from Correction Factors to see if weather is also affecting performance.
So your AFRs are in line with what you want, that is good. IAT is hugely important on turbo hot rods. I'd work on getting your back end performance to last year and then use the water/meth.
101418
 

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Discussion Starter #25
Here's a way to look at your time slip to understand what your changes do. Splits tell you what part of the track your car is working and where it isn't.
Your car is working to 330 feet and then loses steam (except for the +2psi run)

Back end mph gain is pure power level - even after adding boost you're still down a tad.
If last year's time slip was a hero run, leave it out of the mix and grab a time slip that is representative of its average performance.
Lastly, what is it with covering up date and time details on time slips?! From the date, time and place I can calculate ETs from Correction Factors to see if weather is also affecting performance.
So your AFRs are in line with what you want, that is good. IAT is hugely important on turbo hot rods. I'd work on getting your back end performance to last year and then use the water/meth.
View attachment 101418
awesome.. I apologize. looking at the time slips into this kind of depth is new to me. really only have looked into the 60 ft and the 1/4 et and mph haha. So i dont have any duplicate runs from last years previous best, believe most other mph was around 131-132. and around the 11.0-11.1 mark. i'll have to look back at the time slips when i get home to compare.

sorry about blocking out the time and date etc. It was not intentional.

Id have to check my notes, but thinking of it this morning, I do believe i was using the water meth last year on my 10.96 run. Its kind of all making more sense now.

The 10.96 run was October 18, 2019 around 8 or 9 PM i believe
This past weekend was 6/28/2020 around 2 PM. Both at Atco Dragway in Atco NJ
 

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Discussion Starter #26
I think a 1.48-1.53 60'
Will get you to a 6.40 660'
And down to a 10.30 1/4

Screw the MPH you can find that later in the year.
Now i agree. Originally i was concerned at the huge drop. after a few discussions in this thread, I see the cars going in the right direction and It wasn't a fair comparison between the two runs anyway.

I will be working on the 60 ft my next outing. since i got tire spin from leaving on more power. play with the shock adjustment and tire pressures. Guess i've got my homework for next time. haha
 

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Discussion Starter #27
As DA increases you must compensate with more boost. Lets say you raced over the weekend in +3000 DA from your previous times. You would need roughly 1.5 psi more boost to maintain the same power.

Seems like it is all good to me. When you compensated with more boost it got you right back on track with mph. Your new setup is likely running slightly different and/or no wind at your back or it was in your face. Those small details can easily account for your mph difference.
Sounds good. Thank you. Yeah it does seem like it was close to 3000+ DA over the previous run. Just an estimate on dragtimes.com D/A calculator, showing about -800 DA when i ran the 10.96, At 2:00 this weekend where i ran my 10.56 it was 2462+.

I'm learning about how much weather like this effects what i'm looking at. Really didnt expect to see that big of a change at the same track. lol.
 

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Those are some really slow short times for the MPH that you are showing on the time slips. Is this a street car with a high gear ratio in the rear? tell us a little about the combo. ET is made in the short times.
 

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Discussion Starter #29
Those are some really slow short times for the MPH that you are showing on the time slips. Is this a street car with a high gear ratio in the rear? tell us a little about the combo. ET is made in the short times.
Its a street/strip car. its got 3.27 rear gear. going to switch to 3.55s most likely. Its a 331 SBF, single turbo. c4 trans with trans brake. 4000 ish stall converter (dont remember the size, custom for my combination from dynamic converters). car weighs roughly 2900 with me in it. Its on E85. Holley EFI set up. Built it with wanting to keep RPM low to hopefully keep the motor alive.

sorry if its vague. don't know what information is most helpful.
 

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That's what I thought. The car will never 60 ft with that gear ratio in the rear. Put some rear gear in it and it will pick up. You are hurting the engine more by lugging it.
 

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Sounds good. Thank you. Yeah it does seem like it was close to 3000+ DA over the previous run. Just an estimate on dragtimes.com D/A calculator, showing about -800 DA when i ran the 10.96, At 2:00 this weekend where i ran my 10.56 it was 2462+.

I'm learning about how much weather like this effects what i'm looking at. Really didnt expect to see that big of a change at the same track. lol.
Another thing to consider is that the setups are completely different. When using a carb or FiTech style TB injection, an intercooler isn't really necessary because the temp drop under the flange can be between 40-100 degrees. You might be in a situation where your old setup actually had lower manifold air temps than the new intercooled port injection system, especially down the back half of the track. Your new system may be working in reverse. Great temps and fuel metering off the line but as boost is sustained down the back half, temps are rising and the port fuel system isn't quite as good as a carb or TB injection at dissipating heat through atomization.
 

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331 and your keeping the rpm low? You're gonna hurt it.......rod maybe. You need to rpm that little thing. Then it will come to life. My little 331 LS motor see's 7200 at the stripe and shifts at 7000.
 

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My car is screwed up right now. Still tracing the issue. my results. both runs similar weather same track. When car was good; 1.27 /3.69/5.73/[email protected] 2weeks ago with zero tire spin; 1.40/3.84/5.89/[email protected]
So I'd say 60ft doesn't affect mph by very much.
Doug
 

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Id have to check my notes, but thinking of it this morning, I do believe i was using the water meth last year on my 10.96 run. Its kind of all making more sense now.

The 10.96 run was October 18, 2019 around 8 or 9 PM i believe
This past weekend was 6/28/2020 around 2 PM. Both at Atco Dragway in Atco NJ
The day in October is known as mineshaft air; 51*F, -250ft DA, correction factors very near 1, like 1.005 which means it is very close to a perfect weather day for making power.
Last weekend was about the polar opposite; 88* F, 3000ft DA, correction factors around 1.067 and the car should have run around 11.18 to 11.19.
Working backwards, if you get into mineshaft air this fall with your current setup, your buggy could go 10.66 with no wind, which is a big improvement over a 10.96.
The intake air being 37* hotter is a big deal. If you keep datalogs, you can keep track of IAT and look at how it heats up going down track.
The air to air intercooler only slows the rate that IAT is heating up. Throw the water/meth back on and have some fun.
 

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Discussion Starter #37
331 and your keeping the rpm low? You're gonna hurt it.......rod maybe. You need to rpm that little thing. Then it will come to life. My little 331 LS motor see's 7200 at the stripe and shifts at 7000.
On a stock roller ford block RPM is one of the things a lot of people say hurt them. Saving for a dart block but I wanted this one to stay together while I save. Lol. I do know on my 124 mph runs I crossed at like 5500 rpms. Was in 3rd for like 300 RPM. Definitely need to change the rear gear
 

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Discussion Starter #38
My car is screwed up right now. Still tracing the issue. my results. both runs similar weather same track. When car was good; 1.27 /3.69/5.73/[email protected] 2weeks ago with zero tire spin; 1.40/3.84/5.89/[email protected]
So I'd say 60ft doesn't affect mph by very much.
Doug


Sounds good. I’m thinking stuff between change in weather between the two runs and just the overall set up change accounted for most of my mph drop.
 

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Discussion Starter #39
Another thing to consider is that the setups are completely different. When using a carb or FiTech style TB injection, an intercooler isn't really necessary because the temp drop under the flange can be between 40-100 degrees. You might be in a situation where your old setup actually had lower manifold air temps than the new intercooled port injection system, especially down the back half of the track. Your new system may be working in reverse. Great temps and fuel metering off the line but as boost is sustained down the back half, temps are rising and the port fuel system isn't quite as good as a carb or TB injection at dissipating heat through atomization.
I was considering that.About the time the fuel has a chance to cool down the air charge on tbi vs port. Guess if I add the water meth kit back on it’ll help cool it down sooner.
 

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Discussion Starter #40
That's what I thought. The car will never 60 ft with that gear ratio in the rear. Put some rear gear in it and it will pick up. You are hurting the engine more by lugging it.
gearing was definitely one of the higher priority items to change. I just wanted a more fair comparison between the fitech and the Holley so I didn’t want to change anything else. Now that I’ve got an idea for a baseline I’ll swap it out. I’ve got 3.55s waiting to go in. My brother has a spare set of 3.73s laying around so I could try both.
 
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