What's wrong with NASCAR's EFI?

[dieselgeek]

This is pretty much how it works, once they figure out a calibration they don't really change very much, the teams we deal with just call and tell me to duplicate a certain serial # when they need a new one, they run it across the dyno to make sure it works like it's supposed to and that's about it. When they get an idea to try something new they tell me what they want, we make it for them and they flog it until they determine if it's worth pursuing or not, also the drivers don't like the tuners changing carbs on them, I've heard many, many stories I was told that Jimmie Johnson used the same carb for all 5 of his championships with the exception of restrictor plate and road course races which are specialty carbs for those tracks.

So, how many hours of tuning does it take to optimize individual cylinder AFRs? ballpark? I'm not talking about the back-of-the-pack cars, but the leading teams. How many tuning hours did they spend optimizing every cylinder? I'd like to hear more about this process with a carburetor if you're one of the guys who do that. I used a "NASCAR" carb once and the owner claimed it had somewhere between 1000-2000 dyno pulls in it's tuneup.

As Rick said there is no reason to make those kind of pulls on ANY carburetor. While some may make a half dozen other may be as many as 50 if they're trying different settings but you're not going to see more than that. On track tuning is still much more important than a dyno baseline.

Let me make sure I understand what you're saying - 50 pulls max is all that's needed for a Cup Car engine, even when they're monitoring in-cylinder chamber pressure, individual AFRs, and tuning each cylinder by trying individual cam lobe profiles for both the intake and exhaust, *on each cylinder.* 50 pulls or less?? My friend at Roush/Yates tells a wildly different story. I wonder who's right?

[Rick1999]

As Rick said there is no reason to make those kind of pulls on ANY carburetor. While some may make a half dozen other may be as many as 50 if they're trying different settings but you're not going to see more than that. On track tuning is still much more important than a dyno baseline.[/quote]

Let me make sure I understand what you're saying - 50 pulls max is all that's needed for a Cup Car engine, even when they're monitoring in-cylinder chamber pressure, individual AFRs, and tuning each cylinder by trying individual cam lobe profiles for both the intake and exhaust, *on each cylinder.* 50 pulls or less?? My friend at Roush/Yates tells a wildly different story. I wonder who's right?[/quote]

Tell him I said Hi, I probably know him. They certainly flog motors, no question about it, just not the ones that go to the track, they test stuff everyday, all day but most of that is R&D, trying different things looking for power, once they figure out a combination they duplicate it, dozens of times, put it on the pump, make a couple of pulls and if everything works like it's supposed to it goes to the track. Look at it this way, if Jimmie Johnson wants the same carb on his car every week it's not going to be in the shop for more than 1 day anyway. Race day pieces are not tested like that and test pieces don't go to the track.

[Doug Schriefer]

Let me make sure I understand what you're saying - 50 pulls max is all that's needed for a Cup Car engine, even when they're monitoring in-cylinder chamber pressure, individual AFRs, and tuning each cylinder by trying individual cam lobe profiles for both the intake and exhaust, *on each cylinder.* 50 pulls or less?? My friend at Roush/Yates tells a wildly different story. I wonder who's right?

When tuning a carburetor for an engine Yes... As Rick stated there's only so much you can legally do to a carburetor within the rules. There wouldn't be any threads left in the carburetor if you're making changes over 2000 pulls. Guys are going to make a ton of pulls when they're testing other parts, and working on matching components working on valve timing, clearances, etc. but not 2000 pulls just on a carburetor.

[dieselgeek]

Let me make sure I understand what you're saying - 50 pulls max is all that's needed for a Cup Car engine, even when they're monitoring in-cylinder chamber pressure, individual AFRs, and tuning each cylinder by trying individual cam lobe profiles for both the intake and exhaust, *on each cylinder.* 50 pulls or less?? My friend at Roush/Yates tells a wildly different story. I wonder who's right?

When tuning a carburetor for an engine Yes... As Rick stated there's only so much you can legally do to a carburetor within the rules. There wouldn't be any threads left in the carburetor if you're making changes over 2000 pulls. Guys are going to make a ton of pulls when they're testing other parts, and working on matching components working on valve timing, clearances, etc. but not 2000 pulls just on a carburetor.

Then this is misleading information. The carburetor is part of the system as a whole, there is no Cup Car engine (on bigger teams anyways) that's achieving the track tune with 50 pulls, correct? I was told that some teams will spend a hundred hours just on the carb spacer and positioning of the carb on the intake... if all you are counting is "jets and booster" (or whatever) adjustments, sure - 50 pulls seems fine. But that's misleading by a lot... I could say "we can tune an EFI cup car engine in three pulls" if I were using the same logic! Thousands of pulls go into tuning a cup car engine, and hundreds of thousands of dollars are spent on that tuning which includes everything from the carb to a hundred other variables. It's inaccurate to claim that EFI costs any more than a carbureted application in Cup Cars because in both cases these guys flog for every last tenth of a HP, no?

[Rick1999]

Let me make sure I understand what you're saying - 50 pulls max is all that's needed for a Cup Car engine, even when they're monitoring in-cylinder chamber pressure, individual AFRs, and tuning each cylinder by trying individual cam lobe profiles for both the intake and exhaust, *on each cylinder.* 50 pulls or less?? My friend at Roush/Yates tells a wildly different story. I wonder who's right?

When tuning a carburetor for an engine Yes... As Rick stated there's only so much you can legally do to a carburetor within the rules. There wouldn't be any threads left in the carburetor if you're making changes over 2000 pulls. Guys are going to make a ton of pulls when they're testing other parts, and working on matching components working on valve timing, clearances, etc. but not 2000 pulls just on a carburetor.

Then this is misleading information. The carburetor is part of the system as a whole, there is no Cup Car engine (on bigger teams anyways) that's achieving the track tune with 50 pulls, correct? I was told that some teams will spend a hundred hours just on the carb spacer and positioning of the carb on the intake... if all you are counting is "jets and booster" (or whatever) adjustments, sure - 50 pulls seems fine. But that's misleading by a lot... I could say "we can tune an EFI cup car engine in three pulls" if I were using the same logic! Thousands of pulls go into tuning a cup car engine, and hundreds of thousands of dollars are spent on that tuning which includes everything from the carb to a hundred other variables. It's inaccurate to claim that EFI costs any more than a carbureted application in Cup Cars because in both cases these guys flog for every last tenth of a HP, no?

Hendrick Motorsports and Roush Yates Engines probably have (counting back-ups and whats in the back-up cars) about 25 engines a piece at each Cup race, there's just simply not enough hours in the couple of days they have between races to do the kind of testing you are talking about to each and every engine. They flog the living crap out of the R&D pieces and then duplicate the best combo, check it out with a few dyno pulls, and put it on the truck. As far as cost, from what I've been hearing it's going to be very expensive, way more expensive than the carburetors were.

[Doug Schriefer]

Then this is misleading information. The carburetor is part of the system as a whole, there is no Cup Car engine (on bigger teams anyways) that's achieving the track tune with 50 pulls, correct? I was told that some teams will spend a hundred hours just on the carb spacer and positioning of the carb on the intake... if all you are counting is "jets and booster" (or whatever) adjustments, sure - 50 pulls seems fine. But that's misleading by a lot... I could say "we can tune an EFI cup car engine in three pulls" if I were using the same logic! Thousands of pulls go into tuning a cup car engine, and hundreds of thousands of dollars are spent on that tuning which includes everything from the carb to a hundred other variables. It's inaccurate to claim that EFI costs any more than a carbureted application in Cup Cars because in both cases these guys flog for every last tenth of a HP, no?

There are or should I say PLENTY of carburetors that have gone to the track and won races will no where near 50 pulls let alone thousands. Heck we've had carburetors Win Pro-Stock races that had Never been on a dyno EVER. If a team has an existing combination and they're trying a new carburetor setup there would be no reason to make those types of changes. When you're looking at R&D that's a completely different situation than working with existing race combinations or making calibration changes.

As far as the cost comparisons go (Which I didn't bring up) considering all existing teams already had carburetors converting to EFI costs a bunch more money. Let's look at the throttle bodies Holley sells them for about $2100 per unit the larger teams purchased 40 to 50 units each, and then had to pay their own employees to actually assemble them. That's not counting ECU, wiring harnesses, or anything else.

[banjo]

How does everyone thing the durability of the efi systems will come in to play. Between the ecu,fuel injectors and a variety of sensors, to me would seem to be more items with the potential to fail. Where a carb, once it is set up right, is pretty much trouble free. Clean the air bleeds every once in a while and you are good.

How do you think the troubleshooting aspect of things come into play, where you have an electronic component starting to go bad. They will have to hook up a laptop to troubleshoot anything with the system.

How do these system typically handle low voltage situation? Are they more sensitive?

I think the added bit of complexity is really going to cause some havoc on some teams.

[Warp Speed]

]Hendrick Motorsports and Roush Yates Engines probably have (counting back-ups and whats in the back-up cars) about 25 engines a piece at each Cup race, there's just simply not enough hours in the couple of days they have between races to do the kind of testing you are talking about to each and every engine. They flog the living crap out of the R&D pieces and then duplicate the best combo, check it out with a few dyno pulls, and put it on the truck. As far as cost, from what I've been hearing it's going to be very expensive, way more expensive than the carburetors were.

Pretty much the way it is!!

Like both Doug and Rock have stated, there is only so much you can do to a carb (especially rules limited) and that work has been done years ago. VERY little has changed in the past 6-8 years as far as carb set-up.
When we get a new carb, we spend a few hours doing some team specific prep, run it a few pulls on the dyno to be sure there are no problems, and power out-put is as expected, then it goes to a track to be dialed in. We can do some of this "track tuning" on the dyno (and have gotten pretty good at it once they limited testing) but nothing compares to the track, for both carb AND manifold work. Now getting carbs to this point has taken thousands of hours, but over a decades of time, by many involved also! LOL

Now FI is a whole new deal, and believe me, it is NOT saving anyone any money. I believe it is right around $30,000.00 per car (not team) to do it, and that doesn't include engine components (sensors, manifold, TB ect..)!
Most of the starting issues have been either driver error (they are used to spinning it over, flipping the switch and it fires) or an improperly adjusted cam sensor. There has been a few other MINOR issues, but thats about it.

[Mpcoluv]

I think there will be some bugs to work out for sure. There always are when you make a major change like this.
I wonder if some of the problems (more than one driver complaining about) are related to NASCAR trying to make the system "Cheat Proof"?
You would think that if Roush/Hendrick were left to their own devices, they would come up with a fairly awesome system.
That does not seem to be the case now but maybe in the future.
BTW McMurray was talking about dual fuel pumps, and that they tried two electrical and another setup that had one cable driven (Sid Waterman?) and one electric.
I would love to see a diagram of that. Also, one manufacturer tried (is trying?) to run a returnless "deadhead" system.
It will be interesting to see the results in a real race.

[dieselgeek]

Then this is misleading information. The carburetor is part of the system as a whole, there is no Cup Car engine (on bigger teams anyways) that's achieving the track tune with 50 pulls, correct? I was told that some teams will spend a hundred hours just on the carb spacer and positioning of the carb on the intake... if all you are counting is "jets and booster" (or whatever) adjustments, sure - 50 pulls seems fine. But that's misleading by a lot... I could say "we can tune an EFI cup car engine in three pulls" if I were using the same logic! Thousands of pulls go into tuning a cup car engine, and hundreds of thousands of dollars are spent on that tuning which includes everything from the carb to a hundred other variables. It's inaccurate to claim that EFI costs any more than a carbureted application in Cup Cars because in both cases these guys flog for every last tenth of a HP, no?

There are or should I say PLENTY of carburetors that have gone to the track and won races will no where near 50 pulls let alone thousands. Heck we've had carburetors Win Pro-Stock races that had Never been on a dyno EVER. If a team has an existing combination and they're trying a new carburetor setup there would be no reason to make those types of changes. When you're looking at R&D that's a completely different situation than working with existing race combinations or making calibration changes.

As far as the cost comparisons go (Which I didn't bring up) considering all existing teams already had carburetors converting to EFI costs a bunch more money. Let's look at the throttle bodies Holley sells them for about $2100 per unit the larger teams purchased 40 to 50 units each, and then had to pay their own employees to actually assemble them. That's not counting ECU, wiring harnesses, or anything else.

Again, this is misleading information. It's pretty obvious that once a "combination" is developed, it can be easily duplicated. I'm not talking about the Duplicated combinations, I'm talking about the *development* combinations - the exact same detail applies to EFI except that the EFI is simpler and quicker to optimize than the carbureted application.

I wish the carb guys on here were a little bit more realistic and less misleading. This could be an otherwise interesting discussion...

[dieselgeek]

On another topic - cheating. What's a way to cheat with EFI that you couldn't do with a carb? The first thing that comes to mind is closed loop traction control, if they're allowing dual wheel speed sensors...? That would require access to firmware and the McLaren boxes are well developed, locked down pieces - but I'm curious of the guys who work in this sport what ways you could cheat?


Another interesting possibility, I heard a chassis builder from Charlotte claiming that NASCAR was going to actively restrict/control the Engine Management system (remote control) to "keep the races interesting" - while this seems dubious, it IS possible with the McLaren boxes - the same way speeds are restricted on pit road, etc in the other sanctions that use this same system. Remote rev limiting is indeed possible, not sure if they're using it on the NASCAR versions but it makes for an interesting idea.

[Dodge Freak]

When is NASCAR getting these "life saving" air bags ? That is what I like to know, ha ha

That is when I believe air bags save lives

[Rick1999]

Then this is misleading information. The carburetor is part of the system as a whole, there is no Cup Car engine (on bigger teams anyways) that's achieving the track tune with 50 pulls, correct? I was told that some teams will spend a hundred hours just on the carb spacer and positioning of the carb on the intake... if all you are counting is "jets and booster" (or whatever) adjustments, sure - 50 pulls seems fine. But that's misleading by a lot... I could say "we can tune an EFI cup car engine in three pulls" if I were using the same logic! Thousands of pulls go into tuning a cup car engine, and hundreds of thousands of dollars are spent on that tuning which includes everything from the carb to a hundred other variables. It's inaccurate to claim that EFI costs any more than a carbureted application in Cup Cars because in both cases these guys flog for every last tenth of a HP, no?

There are or should I say PLENTY of carburetors that have gone to the track and won races will no where near 50 pulls let alone thousands. Heck we've had carburetors Win Pro-Stock races that had Never been on a dyno EVER. If a team has an existing combination and they're trying a new carburetor setup there would be no reason to make those types of changes. When you're looking at R&D that's a completely different situation than working with existing race combinations or making calibration changes.

As far as the cost comparisons go (Which I didn't bring up) considering all existing teams already had carburetors converting to EFI costs a bunch more money. Let's look at the throttle bodies Holley sells them for about $2100 per unit the larger teams purchased 40 to 50 units each, and then had to pay their own employees to actually assemble them. That's not counting ECU, wiring harnesses, or anything else.

Again, this is misleading information. It's pretty obvious that once a "combination" is developed, it can be easily duplicated. I'm not talking about the Duplicated combinations, I'm talking about the *development* combinations - the exact same detail applies to EFI except that the EFI is simpler and quicker to optimize than the carbureted application.

I wish the carb guys on here were a little bit more realistic and less misleading. This could be an otherwise interesting discussion...

We haven't been mis-leading anyone, Doug and I have done this for a living for a very long time, you are talking about R&D, that's a completely different animal than what goes to the track and actually runs in the race week in and week out. R&D at the Cup level is never ending, they test and test until they come up with something better than their current race package, that package then becomes the race set-up and the job of something better starts all over again. It's been that way forever and will always be that way in the future, carbs or EFI has nothing to do with it, every single nut and bolt on the entire car has gone through the same type of R&D before it's deemed a "race" piece.

[Rick1999]

On another topic - cheating. What's a way to cheat with EFI that you couldn't do with a carb? The first thing that comes to mind is closed loop traction control, if they're allowing dual wheel speed sensors...? That would require access to firmware and the McLaren boxes are well developed, locked down pieces - but I'm curious of the guys who work in this sport what ways you could cheat?


Another interesting possibility, I heard a chassis builder from Charlotte claiming that NASCAR was going to actively restrict/control the Engine Management system (remote control) to "keep the races interesting" - while this seems dubious, it IS possible with the McLaren boxes - the same way speeds are restricted on pit road, etc in the other sanctions that use this same system. Remote rev limiting is indeed possible, not sure if they're using it on the NASCAR versions but it makes for an interesting idea.

I don't know anything about EFI so I couldn't say what is possible but TC is what people are saying. AS far as NASCAR "keeping the races interesting" I don't think they would even consider it, and if they did I don't think they would get away with it, when your car suddenly loses 500 rpm you're gonna know somethings up

[Mpcoluv]

For traction control, you don't need a wheel sensor, you just need to see that the RPM is increasing faster than possible with the tires hooked up (observe the slew rate) and then take out timing to reduce wheel spin.