Ir intake manifolds and carbs

[MadBill]

...Does anyone have actual, on track, Lambda data logged for a big bore, carbed race car?
Can it be shared?

I almost do. I persuaded the owner of the 380" SBF high downforce Merkur road racer I help out on to fit a DLG-1 Innovate Dual Lambda AFR gauge with bungs in each collector plus cylinders #5 & #1/#2, after the latters junction in the right side tri-Y. Intended goal was to move the sensors around, videoing the display in each configuration along with a forward view and audio, allowing correlation with vehicle and engine parameters to:

• Determine if any AFR drift occurred due to the ram pressure at the cars 185 MPH top speed.

• Check for outboard bank lean-out due to ~2 g cornering force.

• Ditto rich/lean surge in 1st gear with/without medium length jet extensions

• Determine required stagger jetting to combat the typical rich AFR of the adjacent-firing cylinders (#6 & #5 with its F.O.)

OK, confession time: Despite my sometimes erudite posts, I'm actually a latter-day Luddite when it comes to electronics. I expect everyone but me knew that you can't video a digital display with ordinary camcorders ; something to do with refresh rates, yada yada yada..

Anyway, the project is on hold until we upgrade to a pair of MTX-A analog units with good old fashioned needles...

[MadBill]

..

• Check for outboard bank lean-out due to ~2 g cornering force.

Make that "inboard".

[frnkeore]

Sorry about that, Bill. My mind said Honk but, my degenerate finger spelled Hook

[Belgian1979]

...Does anyone have actual, on track, Lambda data logged for a big bore, carbed race car?
Can it be shared?

I almost do. I persuaded the owner of the 380" SBF high downforce Merkur road racer I help out on to fit a DLG-1 Innovate Dual Lambda AFR gauge with bungs in each collector plus cylinders #5 & #1/#2, after the latters junction in the right side tri-Y. Intended goal was to move the sensors around, videoing the display in each configuration along with a forward view and audio, allowing correlation with vehicle and engine parameters to:

• Determine if any AFR drift occurred due to the ram pressure at the cars 185 MPH top speed.

• Check for outboard bank lean-out due to ~2 g cornering force.

• Ditto rich/lean surge in 1st gear with/without medium length jet extensions

• Determine required stagger jetting to combat the typical rich AFR of the adjacent-firing cylinders (#6 & #5 with its F.O.)

OK, confession time: Despite my sometimes erudite posts, I'm actually a latter-day Luddite when it comes to electronics. I expect everyone but me knew that you can't video a digital display with ordinary camcorders ; something to do with refresh rates, yada yada yada..

Anyway, the project is on hold until we upgrade to a pair of MTX-A analog units with good old fashioned needles...

With an aftermarket EFI, you can datalog these things. You can even datalog G-forces so that you know when the car is cornering and in what direction. No need for a cam.

[MadBill]

Ummm..., that's where the Luddite in me comes out. Instead of a studying an in-car video at length, thereby getting a lot of entertainment as well as the coordinated data I'm after from the analog dash instruments (including a Magnehilic "H2O gauge), I have to acquire, familiarize myself with and calibrate a laptop, an EFI system and an electronic dash/DA system providing at a minimum for my AFR study RPM, TPS, steering angle, transmission gear, AFR, GPS, sensitive pressure delta data for ram pressure, etc.

[chimpvalet]

Can-Am series cars have got to be about the most enjoyable road racing form to watch - liberty in design, great rumbling V-8 audio, and fast as hell. Remember watching an early Maclaren exiting final turn onto the straight at SIR some years back, looking like the inside front wheel dang near lifting off the pavement on power-shifts.

On mixture stability of carbs, observed a Lola T70 running Weber IDA's at Spa a few years ago running the Eau Rouge esses and popping once neatly out of alternate tailpipes in consistent fashion as it turned one way then the other. Must have been set-up very well, ran strong nonetheless.

[Belgian1979]

Ummm..., that's where the Luddite in me comes out. Instead of a studying an in-car video at length, thereby getting a lot of entertainment as well as the coordinated data I'm after from the analog dash instruments (including a Magnehilic "H2O gauge), I have to acquire, familiarize myself with and calibrate a laptop, an EFI system and an electronic dash/DA system providing at a minimum for my AFR study RPM, TPS, steering angle, transmission gear, AFR, GPS, sensitive pressure delta data for ram pressure, etc.

No you just have to connect it up to power and the wideband. And yes you have to use a laptop, but since you're here I assume you're using a computer already.

[MadBill]

..
No you just have to connect it up to power and the wideband. And yes you have to use a laptop, but since you're here I assume you're using a computer already.

In lieu of the visuals of in-car video, all the aforementioned additional sensor inputs are necessary to put the observed AFR readings into context.

I'm communicating here via an LG desktop with a 24" monitor; awkward to incorporate in a race car. My only laptop is an ancient 5th hand Compaq with a dead battery (so 120 v. required), running Windows 98 and used exclusively for my circa 1996 Dynomation Simulation program which is not supported by anything newer.

[Belgian1979]

Understand.
Anyway Bill, if you really want to see and analyse what an engine does when it's on the track, it's really going to be the only way to see everything at the same time at the tap of the finger. It takes time, but once there it's impressive what you can do with that info. And....you'll be amazed about what can still be learned at the same time.

[RCJ]

We are getting my little grandson (6 years old) in to kart racing.That have a tach called Mychron 5 ,it logs rpm ,gps lap time ,2 temps ,g force and has a play back feature.Its has a add on package that does 02 sensors.The base tach is $500.I don't know how it would transfer to a v8, but this is the cheapest data system I have found.

[MadBill]

Sounds promising; I'll look into it.

[jmarkaudio]

Does anyone have actual, on track, Lambda data logged for a big bore, carbed race car?
Can it be shared?

Chris Uratchko probably does on some I've reworked or built for him. I may have logged some on mine, I've run up to a 2.800 on my 461" SB2.2, I know I have logs up to 2.400. These are drag cars, but even part throttle driving on the return road is decent on mine. Funny thing about logs I've had some big carbs with smoother fuel curves that ran slower than ones not as clean, leads me to believe the Lambda meter isn't telling all...

[CGT]

leads me to believe the Lambda meter isn't telling all...

Their nice to have. But you definitely can't live by them, you see that a lot. So many ways they can lie to you. In fast accelerating drag stuff...acquisition rate would be the big thing I think.

[David Redszus]

leads me to believe the Lambda meter isn't telling all...

Their nice to have. But you definitely can't live by them, you see that a lot. So many ways they can lie to you. In fast accelerating drag stuff...acquisition rate would be the big thing I think.

Depending on the Lambda sensor type and logger, we regularly sample at 100Hz; and on occasion at 1000Hz.

Lambda won't lie to you but it might not tell you what you expected to see.

When Lambda is sampled quickly enough, we no longer see smooth A/F traces. The data looks more like
hash and needs some interpretation. In the real world, you won't see a single value for mixture.

It does not take very long to learn that misfires, malfires and other abnormalities are present.