Dommination of FI cars.

Evan Smith · 12-17-2007, 07:30 AM

Last time I checked the class is called Stock Eliminator, not Nostaliga Stock. The factories haven't made a car or truck with a carb since the '80s.

This is a stupid debate. Based on the comments made by those who are bitching, it has become clear that they do not understand the basics of internal combuation and/or electronic fuel injection. Furthermore, they are terrified of technology, some of which they probably use every day.

The friggin injectors simply flow fuel and are no different than a jet in a carb. It is but one way the EFI system meters fuel. You can over fuel or under fuel with either EFI or carburetion. An injector is simply a solenoid controlled by the computer, which is tuned by an individual. The idea, just like with a carb, is to find the optimal air/fuel ratio for the engine under WOT. How does one know what the proper a/f ratio is? Easy, you use current technology with an O2 sensor and either track or dyno testing to tune your engine. You can do this with a carbureted setup or with EFI. Once you've achieved max power using this tuning method, there is not much more anyone can do to make more power by simply stroking keys or by other measures. If you do not know how somthing works I recommend you educate yourself before making silly comments in an open forum.

The intake and throttle body is what controls (and limits) airflow, the injectors have nothing to do with airflow. Injectors are flow rated at a given psi and raising or lowering the pressure can increase or decrease fuel flow. One can also alter the "pulse width," which is the amount of time the injector stays open once it is commandeed to do so. In most cases, the TB and intake is sized much smaller than a comparable carb/intake setup for any given displacement engine.

Evan

Evan Smith · 12-17-2007, 10:47 AM

Ed,

There is no questioning that the GM LS engine is superior to other small-blocks. But this doesn't speak for all EFI cars. The LS1 started around 325 HP and is now over 370 in some cases. Over time I'm sure it will continute to get factored, so what's the big deal.

It is most certainly is possible to control cylinder-to-cylinder fueling with some EFI systems, but not with others. Getting this right would take eight wide-band a/f sensors in each header pipe, the data-logging to receive the data and quite a bit of time and money spent on testing. This is more than most Stock racers will go through to find what would likely be only a 5-10 hp at most. You could do similar tuning with MSD's adjustable ignition box (on virtually any engine) using adjustable timing to alter the a/f mix.

While I am not a carb expert (or an expert on anything for that matter), I would imagine you could stagger jetting (on some cabs) to affect the a/f ratio using same a/f sensor technique as noted above with simlar expense. Technology will always move forward, that is a fact in any part of life. There are plenty of racers going 1.20, 1.30 or even 1.40-or-further under with carburetors. If EFI is that much better then racers wishing to use such technology can go get at car or truck with EFI. NHRA doesn't require that you or anyone run any particular combination. This is competitive racing with thousands of combinations that NHRA has to try and keep on a level playing field. This, as anyone knows, is virtually impossible. Someone will always be fast, others will be slow.

I think guys with carbs have an advantage because the cars are easier to work on and simpler to operate. Plus, carb racers have had the advantage of far more R&D time since many have been running these cars since the '60s. So maybe we should ban carburetors and only allow 1988 or newer cars in Stock. Of course I'm kidding, but you see my point. Why sit here and complain about everything? I guarantee that over the broad spectrum of classes the majority of cars will be rather equal in performance. There will always be on fast EFI car or combo that eveyone points out, there will be many more with carburetors that fly.

It doesn't take a rocket scientist to know that carbs are not as efficient as EFI. But the real issue that everyone is crying about is weak factors on EFI cars. Namely the LS engines. Many of the fast cars have been hit hard. There have been 9.80 passes in my division by two or three cars. All big-blocks, which is what the LS cars run against. Now that the classes are combined, there will be more heads-up runs and more action from the AHFS. If a racer's goal is to go far under the index, well find a combination that is soft.

Evan

Evan Smith · 12-17-2007, 10:51 AM

Ed,

Another note: From the testing I've done, I can tell you there is very little difference in hp once the a/f ratio is in the "zone." Say your target is 13.0:1, well, running at 12.8-13.2 will give you virtually the same HP. As long as most engines stay in this window, power will vary very little. The trick is knowing cylinder-to-cylinder a/f during the run, which, while some may have, is not someting I've not seen on any Stocker.

Evan

SSDiv6 · 12-17-2007, 11:07 AM

Quote:

Originally Posted by Ed OBrien

Evan
With EFI and 8 injectors is it not possible to adjust each cly. to the proper A/F mix ? With a stock intake and a carb how close can you get ? How many small blocks with a carb run in the 9 second range ? I'm not saying
the FI cars are bad but they have not been factored as they should and think of all the combos in FI cars that Bob Shaw has not got to get LOL sorry Bob I just had to toss that one in . Have a nice day

Ed, there is more than adjusting each injector for each cylinder, and no, it is not an advantage since the mixture is affected by a lot of other variables such as airflow and reversion during the RPM transition. The A/F does not stay the same throughout the RPM band. There is more than F.I. that is helping the new cars go fast. Let's take a look at the following:

1. Better optimized cylinder heads and intakes.
2. Changed firing orders.
3. Lighter crankshafts, rods and pistons.
4. Thinner ring packages.
5. Hydraulic roller lifters.
6. Better oiling systems.
7. Better ignition systems.

I have seen articles in which they have removed the F.I. on LS1 engines, intall an Edelbrock intake and carb with the engine still making lots of power and torque. Many of the crate GM engines are just an LT1 engine with a carb.

Tim Lisson · 12-17-2007, 11:55 AM

Since I purchased a work in progress FI car last year, I hope the thread starter is correct and maybe I can win a race.......but I'll have to say playing with it last year I was really considering a carb.

tim

Dick Butler · 12-17-2007, 12:51 PM

I have not run an injected car. I have seen the results of the original "weak factoring" job done from NHRA in the past for these cars. Some thought probably of getting some new blood in the racing. It worked as many went to the new cars for various reasons.
I have learned alot about the improvements from this post and knowing how it works in SS too. Injected 305 puts out the similar HP to carb models without expensive manifolds.
Seems with all these comments the discussion should move to the one thing which needs to be done to protect "everyone" with any combination who runs S or SS. Tighten up the AHFS and make it more effective in all cases. That would help everyone not just the FI versus carb but the bogus untested motors no one has seen but Bob Dennis or Bob Shaw or other creative builders.
AHFS is the only current method of adjustment. Push for making it better and all the problems can be better with time..
Good discussion of this problem...

SSDiv6 · 12-17-2007, 12:59 PM

Quote:

Originally Posted by Dick Butler

I have not run an injected car. I have seen the results of the original "weak factoring" job done from NHRA in the past for these cars. Some thought probably of getting some new blood in the racing. It worked as many went to the new cars for various reasons.
I have learned alot about the improvements from this post and knowing how it works in SS too. Injected 305 puts out the similar HP to carb models without expensive manifolds.
Seems with all these comments the discussion should move to the one thing which needs to be done to protect "everyone" with any combination who runs S or SS. Tighten up the AHFS and make it more effective in all cases. That would help everyone not just the FI versus carb but the bogus untested motors no one has seen but Bob Dennis or Bob Shaw or other creative builders.
AHFS is the only current method of adjustment. Push for making it better and all the problems can be better with time..
Good discussion of this problem...

Dick...the Olds powered/Cadillac F.I. engines that Bob Shaw and Bob Dennis are running are not bogus; they were in the books for many years. The same applies to Mark Yacavone's Mustang and Neil Smedley's Turbo Pontiacs and Buicks. Do you think because it is not a Chevy, that any other make that runs fast and under the index is bogus? It is just the fact that there are many racers that take the challenge to build cars that others are not willing to.

Bernie Cunningham · 12-17-2007, 01:11 PM

Evan,
Thankyou very much for your input on this thread, very well done, I'm glad you did the typing ! Now all we need is for the whiners to be able to READ and UNDERSTAND the contents, (hopefully a few times to digest it).

Grouping all of the "FI" cars together (all having the same outstanding performance) is really silly too and most FI combos will only run really well in outstanding conditions becauase of the small throttle bodies. Also worth mentioning is that most are 'batch fire' systems with a single coil, fuel injects when the valve is closed, how is that so "dominating". Yes it's possible to individually cylinder time these, but, so can a carb combo! As you stated, only mutli-pak coil systems can use the very expensive and time consuming sequential system for individual cylinder tuning.

I can't wait to hear the outcry when the newest batch of FI cars hit the track in '09.

Rich Biebel · 12-17-2007, 01:27 PM

What Bernie just said is exactly correct. My LT-1 with it's puny throttle body ran well when it was cool out but fell off dramatically in hot weather. I changed my fuel map constantly and tried various setups and was using some feedback trying to get it better. I was able to get it more dialable and consistant but it was also slower. It was frustrating to say the least! I should have paid way more attention to the short converstion I had with Dan Fletcher a few years ago......right before he changed from a EFI powered car to a BB carbureted Camaro.......He seems to have done quite well with an old school combo.....YA THINK!

Dick Butler · 12-17-2007, 02:30 PM

Definition of Bogus "factored" motors : motors which have inadvertantly been overlooked when the factoring was done. 400 chevy, 350 FI chevy, 305 FI chevy are at the top of the list. I find no fault with motors FOUND in the books for years. They exist but Bogus in the sense they are in some cases very much under rated and therefore initially a Killer combination. Many very intelligent racers use this method of qualifying high on the ladder. I am not referring to motors which are paper combinations....Thats another problem...Which would also be corrected by tight AHFS.

12-17-2007, 07:30 AM	#1
Evan Smith Member Join Date: Nov 2001 Location: Tampa Posts: 400 Likes: 7 Liked 115 Times in 5 Posts	Re: Dommination of FI cars. Last time I checked the class is called Stock Eliminator, not Nostaliga Stock. The factories haven't made a car or truck with a carb since the '80s. This is a stupid debate. Based on the comments made by those who are bitching, it has become clear that they do not understand the basics of internal combuation and/or electronic fuel injection. Furthermore, they are terrified of technology, some of which they probably use every day. The friggin injectors simply flow fuel and are no different than a jet in a carb. It is but one way the EFI system meters fuel. You can over fuel or under fuel with either EFI or carburetion. An injector is simply a solenoid controlled by the computer, which is tuned by an individual. The idea, just like with a carb, is to find the optimal air/fuel ratio for the engine under WOT. How does one know what the proper a/f ratio is? Easy, you use current technology with an O2 sensor and either track or dyno testing to tune your engine. You can do this with a carbureted setup or with EFI. Once you've achieved max power using this tuning method, there is not much more anyone can do to make more power by simply stroking keys or by other measures. If you do not know how somthing works I recommend you educate yourself before making silly comments in an open forum. The intake and throttle body is what controls (and limits) airflow, the injectors have nothing to do with airflow. Injectors are flow rated at a given psi and raising or lowering the pressure can increase or decrease fuel flow. One can also alter the "pulse width," which is the amount of time the injector stays open once it is commandeed to do so. In most cases, the TB and intake is sized much smaller than a comparable carb/intake setup for any given displacement engine. Evan __________________ Evan Smith 1798 STK Last edited by Evan Smith; 12-17-2007 at 07:35 AM.

12-17-2007, 10:47 AM	#2
Evan Smith Member Join Date: Nov 2001 Location: Tampa Posts: 400 Likes: 7 Liked 115 Times in 5 Posts	Re: Dommination of FI cars. Ed, There is no questioning that the GM LS engine is superior to other small-blocks. But this doesn't speak for all EFI cars. The LS1 started around 325 HP and is now over 370 in some cases. Over time I'm sure it will continute to get factored, so what's the big deal. It is most certainly is possible to control cylinder-to-cylinder fueling with some EFI systems, but not with others. Getting this right would take eight wide-band a/f sensors in each header pipe, the data-logging to receive the data and quite a bit of time and money spent on testing. This is more than most Stock racers will go through to find what would likely be only a 5-10 hp at most. You could do similar tuning with MSD's adjustable ignition box (on virtually any engine) using adjustable timing to alter the a/f mix. While I am not a carb expert (or an expert on anything for that matter), I would imagine you could stagger jetting (on some cabs) to affect the a/f ratio using same a/f sensor technique as noted above with simlar expense. Technology will always move forward, that is a fact in any part of life. There are plenty of racers going 1.20, 1.30 or even 1.40-or-further under with carburetors. If EFI is that much better then racers wishing to use such technology can go get at car or truck with EFI. NHRA doesn't require that you or anyone run any particular combination. This is competitive racing with thousands of combinations that NHRA has to try and keep on a level playing field. This, as anyone knows, is virtually impossible. Someone will always be fast, others will be slow. I think guys with carbs have an advantage because the cars are easier to work on and simpler to operate. Plus, carb racers have had the advantage of far more R&D time since many have been running these cars since the '60s. So maybe we should ban carburetors and only allow 1988 or newer cars in Stock. Of course I'm kidding, but you see my point. Why sit here and complain about everything? I guarantee that over the broad spectrum of classes the majority of cars will be rather equal in performance. There will always be on fast EFI car or combo that eveyone points out, there will be many more with carburetors that fly. It doesn't take a rocket scientist to know that carbs are not as efficient as EFI. But the real issue that everyone is crying about is weak factors on EFI cars. Namely the LS engines. Many of the fast cars have been hit hard. There have been 9.80 passes in my division by two or three cars. All big-blocks, which is what the LS cars run against. Now that the classes are combined, there will be more heads-up runs and more action from the AHFS. If a racer's goal is to go far under the index, well find a combination that is soft. Evan __________________ Evan Smith 1798 STK

12-17-2007, 10:51 AM	#3
Evan Smith Member Join Date: Nov 2001 Location: Tampa Posts: 400 Likes: 7 Liked 115 Times in 5 Posts	Re: Dommination of FI cars. Ed, Another note: From the testing I've done, I can tell you there is very little difference in hp once the a/f ratio is in the "zone." Say your target is 13.0:1, well, running at 12.8-13.2 will give you virtually the same HP. As long as most engines stay in this window, power will vary very little. The trick is knowing cylinder-to-cylinder a/f during the run, which, while some may have, is not someting I've not seen on any Stocker. Evan __________________ Evan Smith 1798 STK

12-17-2007, 11:55 AM	#5
Tim Lisson Member Join Date: Aug 2003 Location: Solon Springs, WI Posts: 166 Likes: 0 Liked 0 Times in 0 Posts	Re: Dommination of FI cars. Since I purchased a work in progress FI car last year, I hope the thread starter is correct and maybe I can win a race.......but I'll have to say playing with it last year I was really considering a carb. tim

12-17-2007, 12:51 PM	#6
Dick Butler VIP Member Join Date: Oct 2002 Location: Richmond Indiana Posts: 1,196 Likes: 5 Liked 32 Times in 19 Posts	Re: Dommination of FI cars. I have not run an injected car. I have seen the results of the original "weak factoring" job done from NHRA in the past for these cars. Some thought probably of getting some new blood in the racing. It worked as many went to the new cars for various reasons. I have learned alot about the improvements from this post and knowing how it works in SS too. Injected 305 puts out the similar HP to carb models without expensive manifolds. Seems with all these comments the discussion should move to the one thing which needs to be done to protect "everyone" with any combination who runs S or SS. Tighten up the AHFS and make it more effective in all cases. That would help everyone not just the FI versus carb but the bogus untested motors no one has seen but Bob Dennis or Bob Shaw or other creative builders. AHFS is the only current method of adjustment. Push for making it better and all the problems can be better with time.. Good discussion of this problem...

12-17-2007, 01:11 PM	#8
Bernie Cunningham Senior Member Join Date: Jun 2002 Location: Southern California Posts: 560 Likes: 46 Liked 52 Times in 17 Posts	Re: Dommination of FI cars. Evan, Thankyou very much for your input on this thread, very well done, I'm glad you did the typing ! Now all we need is for the whiners to be able to READ and UNDERSTAND the contents, (hopefully a few times to digest it). Grouping all of the "FI" cars together (all having the same outstanding performance) is really silly too and most FI combos will only run really well in outstanding conditions becauase of the small throttle bodies. Also worth mentioning is that most are 'batch fire' systems with a single coil, fuel injects when the valve is closed, how is that so "dominating". Yes it's possible to individually cylinder time these, but, so can a carb combo! As you stated, only mutli-pak coil systems can use the very expensive and time consuming sequential system for individual cylinder tuning. I can't wait to hear the outcry when the newest batch of FI cars hit the track in '09. __________________ Bernie Cunningham 7053 STK Last edited by Bernie Cunningham; 12-17-2007 at 02:02 PM.

12-17-2007, 01:27 PM	#9
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,315 Likes: 25 Liked 544 Times in 213 Posts	Re: Dommination of FI cars. What Bernie just said is exactly correct. My LT-1 with it's puny throttle body ran well when it was cool out but fell off dramatically in hot weather. I changed my fuel map constantly and tried various setups and was using some feedback trying to get it better. I was able to get it more dialable and consistant but it was also slower. It was frustrating to say the least! I should have paid way more attention to the short converstion I had with Dan Fletcher a few years ago......right before he changed from a EFI powered car to a BB carbureted Camaro.......He seems to have done quite well with an old school combo.....YA THINK! __________________ Rich Biebel S/C 1479 Stock 147R

12-17-2007, 02:30 PM	#10
Dick Butler VIP Member Join Date: Oct 2002 Location: Richmond Indiana Posts: 1,196 Likes: 5 Liked 32 Times in 19 Posts	Re: Dommination of FI cars. Definition of Bogus "factored" motors : motors which have inadvertantly been overlooked when the factoring was done. 400 chevy, 350 FI chevy, 305 FI chevy are at the top of the list. I find no fault with motors FOUND in the books for years. They exist but Bogus in the sense they are in some cases very much under rated and therefore initially a Killer combination. Many very intelligent racers use this method of qualifying high on the ladder. I am not referring to motors which are paper combinations....Thats another problem...Which would also be corrected by tight AHFS.

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