Racing Fuel Systems

Re: Lean Side of The Flame

2022-01-27T17:36:19+01:00

Statistics: Posted by JETFAST — Thu Jan 27, 2022 5:36 pm

Re: Lean Side of The Flame

2022-01-02T22:30:50+01:00

I managed to get some data. best numbers were the base line track tune-up, just a little rich and retarded. Operator said i was lean.... i said I was rich.... did not make it much further past that, and the session was aborted.

I believe it would have made 700+ on this pull, had this sweep recorded past 6500.

408 SBC 1050/4150 AD

Fuel SG~~.820 @ 78*
Lamb of~~.82 avg
VE%~~89.5 avg
ME%~~82.7 avg

RPM~~~TQ~~~HP

2900~~430~~240
3000~~441~~252
3250~~449~~278
3500~~465~~310
3750~~475~~340
4000~~507~~386
4250~~547~~451
4500~~555~~476
4750~~560~~506
5000~~570~~543
5250~~566.8~~566.6
5256~~566.5~~566.8
5555~~550~~582
5750~~550~~603
6000~~542~~619
6250~~527~~628
6500~~526~~653

Statistics: Posted by JETFAST — Sun Jan 02, 2022 10:30 pm

Re: Lean Side of The Flame

2021-11-06T20:01:44+01:00

Ordered a new wide band from Innovative. There new LSU 4.9 driver is good for lambda in range of o.5-1.523 / GAFR of 7.35-22.39

Can adjust to display in range of AFR , LAMBDA or percent of O2.

Statistics: Posted by JETFAST — Sat Nov 06, 2021 8:01 pm

Re: Lean Side of The Flame

2021-11-01T17:05:50+01:00

specific Energy ratio, Equivalency ratio, air fuel ratio, lambda ratio, oxidizer to carbon ratio, mole structure of charge, laminar flame speed of velocity, latent heat of efficiency, total jet area, pph of air, pph of fuel, BSFC to VE, DA, ect. all have something to do with it, and are all most factual points of reference to ICE's. If you are on the dyno, you are looking at ratio's, most times you are looking at, and tuning air to fuel. some like it, some think less of it, and some flat out ignore it. most cases very hard to tune for max efficiently with out it, or some other form exhaust gas analyzer. I can not tune EFI without a form of air to fuel reference. most efi systems do not run very well without a reference to lambda of 1.

i have run a lot of nitrous in the range 18:1 A/F ratios with c25. very cold fuel with alot of RVP. Most basic spark ignitions can not carry a flame close to or even past lamb of 1. as it begins to misfire. addition of nitrogen (in nitrous) helps extends the lean burn efficiency limit of petrol to 1.0-1.2 with methanol and ethanol increase 1.2-1.5 respectfully.

408 SBC 4150 "1050" annular meth/nitro blend SG is around .850 @ 68. with plans of tipping a little h2o2 in the mix.

will be splitting the frog hairs 4 ways on the dyno later this month, with 8 egt and 10 o2 sensors, and see what's good...or not.

Statistics: Posted by JETFAST — Mon Nov 01, 2021 5:05 pm

Re: Lean Side of The Flame

2021-11-01T10:05:24+01:00

Darrin Morgan has a few YouTube videos where he talks in depth about de-atomization in the intake tract. So much is counter intuitive as what shapes look and may well flow the best tend to be conducive to fuel sticking to walls, floors and roofs.

Statistics: Posted by Right hand drive — Mon Nov 01, 2021 10:05 am

Re: Lean Side of The Flame

2021-11-01T06:53:13+01:00

Excellent question! Fuel drops out of suspension onto to manifold/port walls due to lower air speed?

Statistics: Posted by GTO Geoff — Mon Nov 01, 2021 6:53 am

Re: Lean Side of The Flame

2021-10-31T23:49:15+01:00

Question: if you have to jet it richer, where does the extra fuel (while making less hp) go? Eventually unburnt in the exhaust?

Statistics: Posted by DrCharles — Sun Oct 31, 2021 11:49 pm

Re: Lean Side of The Flame

2021-10-31T07:15:47+01:00

Nowhere near. One was a single plane and the other a dual. It was on a 500” BBC. The airspeed was very high for the dual plane so I suspect the fuel was having a hard time making the turns. I was shocked how much more jet it wanted.

Paul

Statistics: Posted by FC-Pilot — Sun Oct 31, 2021 7:15 am

Re: Lean Side of The Flame

2021-10-28T22:40:39+01:00

Was the peak power the same hp for both intakes?

It would have been interesting to see the AFR for individual cylinders. Sounds like good wet flow is important

Statistics: Posted by DrCharles — Thu Oct 28, 2021 10:40 pm

Re: Lean Side of The Flame

2021-10-28T21:41:19+01:00

When we are tuning stuff on the dyno I don’t tune around the AFR. I watch AFR but also watch egt’s and plugs and find best power. From there the afr is just a number to me as we are looking for best power.

I have tested the same engine but with two different intakes. One had really good wet flow characteristics and the other was poor. The each made peak power with a full point difference of AFR from the other. This was with the same carb as well.

Paul

Statistics: Posted by FC-Pilot — Thu Oct 28, 2021 9:41 pm

Re: Lean Side of The Flame

2021-10-28T17:29:01+01:00

FA car. no electronics. so i run a go pro on the gauges.

this at the stripe. fastest pass of the season. not sure exactly where i was on this side of the flame, as this gauge only reads to lambda of 1.22. #1 egt did not even crack 1200*

Statistics: Posted by JETFAST — Thu Oct 28, 2021 5:29 pm

Re: Lean Side of The Flame

2021-10-26T18:18:22+01:00

...

Statistics: Posted by JETFAST — Tue Oct 26, 2021 6:18 pm

Re: Lean Side of The Flame

2021-10-26T16:51:25+01:00

If you mean full-power mixture, no... I keep my (WOT) AFR around 12.5, maybe 13 at leanest.
Now for cruise, 15:1 works fine and I could probably go even leaner

Statistics: Posted by DrCharles — Tue Oct 26, 2021 4:51 pm

Lean Side of The Flame

2021-10-26T16:36:22+01:00

Anyone tune around stoich....with petrol, ethanol, or methanol?

Statistics: Posted by JETFAST — Tue Oct 26, 2021 4:36 pm