Tune up question

[Cparten]

Ok experts, I need some advise. Last year we spent a lot of time trying to find our tune up. A VERY long story short. we were stuck in the 8.00-8.10 range trying different tunes. At the end of the year we were able to get a best of 7.90 @ 166. We went to the dyno after the season and did some tuning. found more power by landing on a tune up "close" to what we had. This season we have gone out testing and have not been able to get back to the 7.90 range and again were stuck in the 8's. This past weekend was the oldies but goodies race at woodburn Oregon. In order to qualify we needed to be into the 7's. After struggling in testing on Friday night test and tune, Paul New came over to offer his advise. His words of wisdom was  "put your 7.90 tune back in!" xxxx, Why didn't I think of that!!! Saturday qualifying we went out with our 7.90 tune in it and lo and behold we ran a 7.84 at 169!! (thanks for waking me up Paul!!). We are now qualified for the B field. Great!! This tune took us all the way to the final on Sunday!! We lost the final but only by a very slim margin. Math worked out to .003 of a second loss. It was awesome!! Great race!!
   Here is my question. The tune up is where I need help. Don't laugh its out there. The main pill is a 69. running a high speed bypass with a 55 pill. the highspeed opens at the hit so the entire run is on the main pill as well as the highspeed. The plugs show good heat (still a little rich). My question is. How do I figure out what main pill will get me to the 2 combined pills so I can get back to a correct tune up?
 "note to self, Don't tune with dyno!!"

415 small block chevy
hilborn 2 3/4 stack

   Again In want to thank Paul for his help!! We had a great weekend

[glofria]

Are you adjusting the timing at all? If your injected, you may need to compress the air more.

[Cparten]

The timing is locked in at 38* I have tried other settings and this is where it likes it the best.

[glofria]

Then the next thing would be to try a bigger how pressure pill or a secondary bypass (somewhere after the pump) set at a higher pressure relief.

What you have is low pressure bypass (probably set between 9-15 lbs.), now you need a true high speed lean-out bypass that will take more fuel away down track and keep the car pulling to the end.

[denverflatheader]

Cparten – my thinking is two different paths to accomplish.  First you could use math to calculate each individual pill area (i.e. main & high speed) and add the 2 answers together as a starting point for selecting your new “single” main pill size.  This however lacks “true flow” accuracy.

For me, the preferred path would be to send both your “Main” pill and “High Speed” pill to FIE and have them professionally flowed; per the FIE website, Spud charges $10.00 per pill for this service.  Then, purchase a new “Main” pill from FIE that has been professionally flowed to match the combined flow of your two old pills. This provides a precise method to match your current setup and eliminates using a “high speed” mechanism for tune-up at the hit.  Alan

http://www.fuelinjectionent.com/menu2.php   (Look under the Mechanical Fuel Systems category)


p.s. plus as glofria wrote, you can then setup your “high speed” separately to operate properly as a “high speed” lean out down track.

[Cparten]

Then the next thing would be to try a bigger how pressure pill or a secondary bypass (somewhere after the pump) set at a higher pressure relief.

What you have is low pressure bypass (probably set between 9-15 lbs.), now you need a true high speed lean-out bypass that will take more fuel away down track and keep the car pulling to the end.

I am looking to land on what a starting point for what would be for a main pill that would return the same amount I am currently returning with the main and highspeed combined. This way I can use the main as intended. That would allow me to use the highspeed as it is intended. Example what I am talking about is, if my main is a #69. How much do I need to increase it to flow as much as a #69 + #55 Which is my highspeed) Would a #73 flow the same? Is there a formula to figure this?

[Cparten]

Then the next thing would be to try a bigger how pressure pill or a secondary bypass (somewhere after the pump) set at a higher pressure relief.

What you have is low pressure bypass (probably set between 9-15 lbs.), now you need a true high speed lean-out bypass that will take more fuel away down track and keep the car pulling to the end.

I am looking to land on what a starting point for what would be for a main pill that would return the same amount I am currently returning with the main and highspeed combined. This way I can use the main as intended. That would allow me to use the highspeed as it is intended. Example what I am talking about is, if my main is a #69. How much do I need to increase it to flow as much as a #69 + #55 Which is my highspeed) Would a #73 flow the same? Is there a formula to figure this?

Denverflathead,  Spud was my next call as he originally flow this system for me. Great idea to have both pills flowed.

[glofria]

Seems like you already have a starting point. Now you can either go one way or the other on the Main (bigger or smaller). Use your previous slower runs as a reference for comparison.

Is this a Enderle or Kinsler set up?

These are goo books to have and I  recommend having a set.
https://racecarbook.com/

[Paul New]

Chris, glad you were able to get into he show this last weekend!
As far as the pill size see below
55 has an area of .002376
69 has an area of .003739
Which equals an area of .006115
88 has an area of .006082
89 has an area of .006221

Now this is just using math not real world flow.

[Cparten]

Chris, glad you were able to get into he show this last weekend!
As far as the pill size see below
55 has an area of .002376
69 has an area of .003739
Which equals an area of .006115
88 has an area of .006082
89 has an area of .006221

Now this is just using math not real world flow.

Paul, This is what I was looking for. A solid starting point. I am going to set it up with a 88 and not run the highspeed to see what it does. I have a feeling it will land around 90. We have ordered a DataMaxx system and will have it on the car the next time we go out. hopefully in 2 weeks or as my schedule allows. This should help me nail it down as well as help setting up the highspeed once I get the main set.
 Thanks again Paul! I owe you a beer.......or 2

[Cparten]

Just for fun....Here is a video of the final on Sunday from the gopro

[opa1]

Good video! Had the eye shake and all.

[glofria]

Yes, great video. You can see the other guys front wheel pull ahead the last couple of 100'. That's his high speed lean-out working.

The engine isn't popping so your not running out of fuel. next time lean it down some and see if it pulls harder.