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Discussion Starter #1
Jim I was wondering if you had tested or autotapped your T-1 setup yet. I have just recently switched to the sidewinder with the T-1v filter. By looking at the filter though I think it would be more beneficial to run it with the tric. But then there would probably be too much airflow for the cars injectors to handle. Will the 30's make it too rich-therefore would i need to buy a transalator to lean it out or will the computer compensate for it all. Thanks-I'm hoping to hit 118mph this weekend with the 02 and the sidewinder up from my best of 116.87. I think with the tric tunnel and the t-1v filter-ported tb and 30lb injectors and off-road exhaust 120+mph is achievable without headers-that's some serious bolt on power. What do you think? Hurry with your suggestion as I only have 2 more weeks after this weekend to test as the tracks shut down for winter. Thanks
 
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The 30# Injectors are just right on the 2002 Z06

YES, we have AutoTapped the injectors, and guess what. The LT Trims are perfect. All fuel cells 1-17 are back to 14.6:1 a/f ratio (takes about 25 miles) with WOT at 12.6:1.

The dyno numbers are improved over our initial pulls quite a bit. Nothing is needed on the 02 with the T-1 Intake, other than bigger injectors. This size injector using 58 psi fuel pressure should provide sufficient head room for airflow to around 480 HP at 80% duty cycle.

We are no longer posting dyno numbers on the forum, however.


Jim
 

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Re: The 30# Injectors are just right

Halltech said:

We are no longer posting dyno numbers on the forum, however.

Jim
Why?
 

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For what is is worth, I had a recent extended discussion with Chuck Mallet, who is a well known tuner in the Corvette world. Mallet told me that he did a lot of work for Chevrolet during the development of the Z06. This is also stated in the September edition of Car and Driver Magazine, the issue in which they did a super tuner shoot-out. Mallet told me that the stock injectors on the Z06 are good for up to 500 h/p, therefore do not need to be replaced unless you are anticipating going over 500 at the crank.

Before replacing injectors, you may want to discuss this with him yourself - he should know, if anyone does...


My $.02
 

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Discussion Starter #5
500hp?

i'm not saying that Mallet does not know what he is talking about but there is no way the stock (26-28lb-i'm not sure)injector at the rated 45 psi can handle 500hp. maybe at 80-90psi it could support those #'s but not at 45psi. I don't have my formula's for figuring out injector size with me but you can to many of the sites on the internet( RC engineering) and punch in some #'s and it will tell what injector is needed for that level of horsepower.
 

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Well, Vortech, it sounds like you think Mallet is completely wrong in his assertion. Why not call him and discuss it with him directly? Seems strange to me that a guy who GM has chosen to work with on the Z06 would be so wrong. But, I certainly will admit freely that I am not knowledgeable enough to question either his, or your views. For the moment however, I would tend take Mallet's viewpoint, because it is supposedly his business to know this kinda stuff.

Now here is a little gem for digestion. Last night at the local cruise -in this incredibly well set up LT-1 vette shows up replete with blower, nitrous, etc... The guy is a well known street racer for $ and he is making around 675 h/p according to his helpers. Oh, btw, according to one of his "wrenches" he is doing this using 24 lb injectors....

So, what's with that - as my kid would say....:D
 

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Discussion Starter #7
FMU

Ever heard of a FMU-all blower cars run one-except the ones with a returnless system. This enables you to use a smaller injector and ramp the pressure as boost builds. for example the vortech kits come 12:1, 10:1, 8:1, 6:1 and 4:1 that means for everypound of boost the fuel pressure rises accordingly. I love how people throw around 600 hundred 700 hundred hp like it's nothing-all i have to say is line 'em up and show me the money. My 91GT( mustang makes 700hp and runs a 55lb injector which under 20lbs of novi boost goes up to 65psi up from 35( it runs [email protected]), and its hardly drivable on the street. For the street my 89 lx makes around 475 hp(11.00'[email protected] on radials)-it runs a vortech making 10lbs of boost and has 36lb injectors which run at 65psi as well under full boost. I could have run 30lb'ers but then would have to spike the pressure say another 20 psi (80psi under boost) but then as you should now as fuel pump pressure goes up volume delivered goes down-so a 255lb an hour pump which delivers that at 45 psi only can deliver say 190 at 70psi. You must of misunderstood what Mallet says as i'm sure his vortech equipped C5's run much bigger injectors than stock-I would guess anywhere form 36 to 42lb's. As for the guy with 675 hp-lets see a timeslip-plus the nitrous is a wet system which flows nos and fuel and cools the charge of the blower-very hard system to set up especially now that we have the watercooled intercollers available and wideband 02's to tune. this is just from my humble experience building and tuning and racing 7,8 and 9 second blower stangs for the last 10yrs.
 
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2002 Fuel Injectors are rated at 24.3 lbs/hr. @43 psi

The stock injectors: Here's the actual page for calculating injector size by RC Engineering. Russ Collins is the Guru of fuel injection and does this for a living.

http://www.corvettec5.com/cgi-bin/SoftCart.100.exe/newsite/technical[1].htm?L+scstore+limt8722+1003773043

Try this-Put Insert 500 HP; 8 cylinders; .50 Brake Specific Fuel Consumption; .80 max duty cycle; 58 psi (static fuel pressure on the Z06)

Then take 360 HP and insert it at the top and recalculate. Notice that the injector size is the same as the 2002 injectors we tested.
Now change the duty cycle and the HP until you reach 405 HP. You begin to see that the duty cycle of the injectors goes way out of the 80 % range in order to reach the 405 HP mark.

Also, Katech provides 36# injectors with their LS1 to Z06 conversion package which is rated at 464 HP.

Chuck is probably referring to the 2001 Z06, which had larger injectors (somewhere around 30#) If you increase the duty cycle of the 30# injectors, they could reach the 500 HP mark, but this would not be the ideal injector for the job since the injectors would be running at 90% duty cycle.

The 2002 injectors are rated at 255cc/min @43 psi or static 24.3 lbs/hr. The same size as our 2000 LS1 injectors.

They have already made 432 HP on our 2002, but check out what duty cycle they are running at to do it.

GMs use of the smaller injectors was just right for the stock airbox and the smog certification needed with the new cat system. They work. The problem is what happens when you decide to add more airflow to the engine?

Chuck is not wrong, he is using numbers from the previous 2001 Z06. Halltech has not tested the 2001 injectors, but they were larger than the LS1 injectors in 2001. If there is an interest in this information, we could get a set for testing.

Once again, thanks for the information.

Jim


:) :)
 
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Re: Re: The 30# Injectors are just right

TAMUz06 said:
We have been accused of taking up too much bandwidth, and the dynos we have provided will be posted on our website, where bandwidth is not a problem.


Best,

Jim
 

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I don't know where this accusation came from but since I own the site, *I* will decide who's "wasting" bandwidth......

Jim, we would like those sheets and I'll be glad to host them over here, along with any other vendor that wishes to host dyno sheets. This is important information and we won't skimp on bandwith to provide users the information they need. Ever.

JC
 
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It wasn't you

During a debate regarding dyno numbers, there was a .02 given and that statement was made regarding our posts.

I think that thread was deleted. Maybe you could resurrect the thread?

I was defending another forum supporting vendor, and asked that dyno sheets accompany statements of power deltas. That's all. I expect folks that dyno our products to post their numbers and back it up with dyno sheets. Seems fair.

We have been through this on another forum, where our T-1 was dynoed with poor results. The customer never contacted us prior to the post, which hurt Halltech's initial claims. Since then, we discovered the problem with his system and made a free correction. After a redyno, he made almost 16 HP over stock, which was the same as our dyno numbers. This customer meant no harm, I'm sure, but everything that is posted on the forums, have consequences for vendors and manufacturers.

We have made substantial gains with our T-1 system, tossing out some minor components, like the spark plugs, and adding others that have made a big difference.



Jim
 

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I wish I could bring it back but it's gone. I do remember the thread getting quite heated.

I also, wish that people would either state that what they are posting is of their opinion rather than fact.

As with ANY vendor, their reputation should not be put on the line with hearsay, no matter who they heard it from.

We only want the facts......and in the case of the T1, I think we are starting to see that these are, in fact, real gains.

JC
 

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The only thing I have to add to this is that the S.A.M. Camaro is using 28lbs rather than 24lbs injectors out of a 99 or 2000 model LS1 and a stock fuel system, and running in the 10s with a modified program.

It sounds as if Jim has done his homework on this. I am sure that once the motor starts getting more air, its going to need more fuel. At some point you are going to have to re-optimizer the program it runs. Just like back in the day when you'd throw a Hypertech chip in the car and pick up the timing and such that GM "left on the table". Not saying it won't work stock, but it could work better.

This either means re-doing the stock program, or supplying the car with more fuel via bigger injectors. The stock map only has so much room. As we tune our cars to a higher level of efficiency, it becomes important to check this stuff. You may be leaving power "on the table" by not looking at what the computer is telling you. My car is bone stock, but as I start working on it, this will be something I will pay attention to. As it is something I have to check in some of my other cars.

I know on many cars, you can cover this up by turning up the fuel pressure (except on our cars since fuel pressure management is so bass-ackwards), but you can only go so far before the injector looses efficiency. It is much preferred to fix fuel delivery by program or sizing rather than just cranking fuel presure sky high. In my experience, typically you can go about 10% bigger on injector sizing before the program must be completely re-done.

Injector ratings are always done at 43lbs. So you have an apples to apples comparison. But me personally I prefer having a little too much injector in a car. This has always given me a little "headroom" to work with. For instance in my GN I would best just on the small side with 55# injectors, so I put 72# in. This give me way more injector than I need, but I won't even run short up top, where it is the most dangerous.

If you plan on spraying your car for instance with a "dry" kit, a little extra injector wouldn't hurt either....
 
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You've got it.

J-Rod said:
The only thing I have to add to this is that the S.A.M. Camaro is using 28lbs rather than 24lbs injectors out of a 99 or 2000 model LS1 and a stock fuel system, and running in the 10s with a modified program.

It sounds as if Jim has done his homework on this. I am sure that once the motor starts getting more air, its going to need more fuel. At some point you are going to have to re-optimizer the program it runs. Just like back in the day when you'd throw a Hypertech chip in the car and pick up the timing and such that GM "left on the table". Not saying it won't work stock, but it could work better.

This either means re-doing the stock program, or supplying the car with more fuel via bigger injectors. The stock map only has so much room. As we tune our cars to a higher level of efficiency, it becomes important to check this stuff. You may be leaving power "on the table" by not looking at what the computer is telling you. My car is bone stock, but as I start working on it, this will be something I will pay attention to. As it is something I have to check in some of my other cars.

I know on many cars, you can cover this up by turning up the fuel pressure (except on our cars since fuel pressure management is so bass-ackwards), but you can only go so far before the injector looses efficiency. It is much preferred to fix fuel delivery by program or sizing rather than just cranking fuel presure sky high. In my experience, typically you can go about 10% bigger on injector sizing before the program must be completely re-done.

Injector ratings are always done at 43lbs. So you have an apples to apples comparison. But me personally I prefer having a little too much injector in a car. This has always given me a little "headroom" to work with. For instance in my GN I would best just on the small side with 55# injectors, so I put 72# in. This give me way more injector than I need, but I won't even run short up top, where it is the most dangerous.

If you plan on spraying your car for instance with a "dry" kit, a little extra injector wouldn't hurt either....
You are dead nuts on. Couldn't have said it better myself.

One example comes from Darren at R&D Dyno. He took a stock 2000 C5 and sprayed NOS in front of the car during a dyno session. The gain was 80 RWHP. If you could see the dyno, however, the power delivery was a joke. The MAF took care of adding more fuel, but you could see that all the increases were spiked HP gains with many dropouts during the pull. Some may have been knock retard, but without an increase in fuel pressure, the stock injectors were at 100% duty cycle.

Jim
 
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I own a Mallett 435 so I have talked to Chuck in the past about this and also consider he outsources the PCM coding and the guy he used to use was telling him things not all of us would agree to.

Pre LS6 intake would have a different view on this since the intake was a delimitung factor so adding more jiuce was not a concern to Mallett back when my'99 Mallett was being done.

Going to larger injectors is just not for more juice, but the ability there is in having larger injectors.

If you had to run 5 miles, woulf you rather do it on a straight level road or one that is going uphill, meaning the stock injectors might do the job but you have to run them at the edge of their duty cyvle whereas with larger injectors, its like running downhill, a lot less stress since the larger injectors have to work in a lighter duty cycle.

Next is tuing. with the stock iinjectors, if the fuel trims are always far from zero, the PCM is always trying to fight the battler to get the trims back down to zero and injectors have to have more "on time" to try and make the difference up.

You could tune the tables, like with a MAF translator but recall that when you tune to go richer, means more load, which means less WOT timing.
But using a larger injector, the tables would be richer, thus you tune in for leaner, thus less load, you gain more WOT timing.

So the larger injectors give you a lot more tuning abilty to achieve best tune for best performance, plus the injectors do not even have to rich the norm 80% duty cycle.

BTW, my Mallett 435 ( which meant flywheel HP) with the SVO 30 injectors ( about $210 ) and MAF tuning now is 470 HP, but this is also due to me swapping the older style intake manifold with the LS6 version.
RWHP went from 383 to 407, thus it's not that the stock ones would not work, it's the larger ones allowed me to better overall tune the AFR, increase timing and control engine knock.




BLEUBYU said:
For what is is worth, I had a recent extended discussion with Chuck Mallet, who is a well known tuner in the Corvette world. Mallet told me that he did a lot of work for Chevrolet during the development of the Z06. This is also stated in the September edition of Car and Driver Magazine, the issue in which they did a super tuner shoot-out. Mallet told me that the stock injectors on the Z06 are good for up to 500 h/p, therefore do not need to be replaced unless you are anticipating going over 500 at the crank.

Before replacing injectors, you may want to discuss this with him yourself - he should know, if anyone does...


My $.02
 
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Good Points

I would agree with TeamZR1 in large part.

Our AutoTap results are near perfect on our 2002 Z06 with the 30# injectors, Halltech T-1, Ported TB.

The dyno we did initially from 350.8 RWHP (stock) to 367 RWHP was done within 30 minutes, with no change in injectors or any other mods.

The stock 02 injectors are running at 90% duty cycle to make that HP (434 Flywheel) and running the larger injectors has provided more headroom and brought the duty cycle back down to around 80%, with the LT Trims returning to near 0 in most of the 17 fuel cells, just as TeamZR1 suggested.

The injectors will normally not add HP, unless the stock injectors are so lean as to keep the Long Term Fuel Trims way into the plus side. When you go into WOT, part of the lower trim table is added to the WOT open loop cell 22, hoping it is correct. It is usually not. This is the programmers challange.

Higher fuel pressure is not an option with the Z06, nor is programming at this point in time, since no one is interested in this area at this time. We wrote to one programmer and never heard back. Too busy?

:-? :-?

Jim Hall
 

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More Calls - Chuck Mallet & RC Engineering

Made calls to both RC Engineering (RC) and Chuck Mallet (CM) today. I am familiar with RC's reputation and work, and definitely agree when it comes to injectors, they are the "goto" people. RC cleaned and blueprinted my ZR-1 injectors (all 16 of 'em) which helped that car put out some pretty healthy numbers. I believe those injectors put out 30 lbs each.

I talked to John at RC and got some interesting information. John confirmed that the '02 Z06 was using 24.3 lb (255) injectors. He did not know what the '01 Z06 was running, so he could not tell me definitively that they were smaller, but he had "heard" that. He did tell me that RC does not want to see injectors running at more than 85% of their duty cycle. As he explained to me, much beyond 85%, injectors can go into full static mode, meaning they are wide open all the time. John indicated to me that the stock injectors should be adequate for bolt-ons such as intakes/headers, but once you go into the motor, a larger injector is definitely needed. So, from RC's perspective, if I understood them correctly, larger injectors are definitely required when going beyond the modest gains obtained via bolt-ons. John further went on to tell me about the "20% rule" which is that you can usually install up to a 20% larger injector without having to reprogram the ECM. In the case of RC, that would mean migrating from the 255 cc stock injector to either their 270 or 310 cc injector set. BTW, RC uses Lucas injectors, not Bosch units which our cars are equipped with. Divide the cc number by 10.5 to get the lbs rating - so 310 cc equates to 29.5 lbs...

I next called CM to revisit the injector issue with him, since there were some concerns expressed that I might have misunderstood what he told me when we last chatted. CM corroborated GM using the smaller 24.3 lb injector in the '02s. CM believes the '02 injectors are running a duty cycle in the mid sixties. He said that a 26 lb injector was used in the '01 Z06s. When I asked why they downsized the injector, CM said that is was because GM wanted to get the absolute cleanest emissions they could, while making this power level. I asked him if I had misunderstood him earlier when I thought he said that our stock injectors were good for 500 h/p - I wanted to make sure I was quoting him correctly. CM responded that I may have slightly misunderstood what he was saying - he says that the stock 24.3 lbs injectors should be able to support approximately 475 h/p, and the 26 lb injectors would support approximately 500 h/p. As a side note of interest he told me that he is using his '99 car as a testbed for GM work on the C6 version of the Z06 - it is on the dyno today..

So there you have it, some conflicting information from two pretty reputable sources. This happens so often when trying to ferret out what the real deal is. And as always, it does present both an intellectual (and budget) challenge to those of us determined to make the best choices. In my particular situation, I will choose my exhaust (headers) mod sometime this winter, then go back to Woodbridge dyno and have John Sealock do some comprehensive dyno tuning. I will let the data and my own comfort level drive my decision re injectors or any other additional mods. I continue to believe that RC Engineering is the ultimate authority accessible to us for injectors, fuel pumps...
 

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Re: More Calls - Chuck Mallet & RC Engineering

BLEUBYU said:
Made calls to both RC Engineering (RC) and Chuck Mallet (CM) today. I am familiar with RC's reputation and work, and definitely agree when it comes to injectors, they are the "goto" people. RC cleaned and blueprinted my ZR-1 injectors (all 16 of 'em) which helped that car put out some pretty healthy numbers. I believe those injectors put out 30 lbs each.

I talked to John at RC and got some interesting information. John confirmed that the '02 Z06 was using 24.3 lb (255) injectors. He did not know what the '01 Z06 was running, so he could not tell me definitively that they were smaller, but he had "heard" that. He did tell me that RC does not want to see injectors running at more than 85% of their duty cycle. As he explained to me, much beyond 85%, injectors can go into full static mode, meaning they are wide open all the time. John indicated to me that the stock injectors should be adequate for bolt-ons such as intakes/headers, but once you go into the motor, a larger injector is definitely needed. So, from RC's perspective, if I understood them correctly, larger injectors are definitely required when going beyond the modest gains obtained via bolt-ons. John further went on to tell me about the "20% rule" which is that you can usually install up to a 20% larger injector without having to reprogram the ECM. In the case of RC, that would mean migrating from the 255 cc stock injector to either their 270 or 310 cc injector set. BTW, RC uses Lucas injectors, not Bosch units which our cars are equipped with. Divide the cc number by 10.5 to get the lbs rating - so 310 cc equates to 29.5 lbs...

I next called CM to revisit the injector issue with him, since there were some concerns expressed that I might have misunderstood what he told me when we last chatted. CM corroborated GM using the smaller 24.3 lb injector in the '02s. CM believes the '02 injectors are running a duty cycle in the mid sixties. He said that a 26 lb injector was used in the '01 Z06s. When I asked why they downsized the injector, CM said that is was because GM wanted to get the absolute cleanest emissions they could, while making this power level. I asked him if I had misunderstood him earlier when I thought he said that our stock injectors were good for 500 h/p - I wanted to make sure I was quoting him correctly. CM responded that I may have slightly misunderstood what he was saying - he says that the stock 24.3 lbs injectors should be able to support approximately 475 h/p, and the 26 lb injectors would support approximately 500 h/p. As a side note of interest he told me that he is using his '99 car as a testbed for GM work on the C6 version of the Z06 - it is on the dyno today..

So there you have it, some conflicting information from two pretty reputable sources. This happens so often when trying to ferret out what the real deal is. And as always, it does present both an intellectual (and budget) challenge to those of us determined to make the best choices. In my particular situation, I will choose my exhaust (headers) mod sometime this winter, then go back to Woodbridge dyno and have John Sealock do some comprehensive dyno tuning. I will let the data and my own comfort level drive my decision re injectors or any other additional mods. I continue to believe that RC Engineering is the ultimate authority accessible to us for injectors, fuel pumps...
Thanks for following up, Bleu. The C6/Z06 conversion note was especially sweet:)

With all you know now, would you buy injectors for a header/intake equipped 01 or 02 car that has no further mod plans?

When tuning for the 02 get's rolling, I bet we some positive tweaks.


RG
 

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I think that if add headers to my intake and exhaust mods, injectors might be some good insurance on keeping the trims nice and the injectors in the comfort zone......

It may not be necessary, but a buffer zone is always nice.......

JC
 

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RG, based on what I understand at this point, and what I have learned via my follow-up calls, it would seem that the '01 cars with their 26 lb injectors, would not need new injectors for intake and exhaust bolt-ons.

However, the '02 cars are certainly much closer to utilizing the maximum acceptable duty cycles of their injectors. So that is why I will do some extensive dyno testing/tuning with John Sealock after getting headers. As an interesting added note, the RC folks told me that running the injectors at a higher duty cycle (e.g. 80% as opposed to say, 70%) does not shorten their life. I would have thought otherwise.

It looks like it would run around $700-800 for a set of the RC 310 cc injectors (don't see the point of only upgrading to the 270s) so I want to be sure I need 'em before buying them. Of course, that does not include installation. Also, I do not know how changing the injectors would effect our warranty coverage - I need to look into that. My ordering dealership - Criswell - is pretty cool with bolt-ons, but I don't know about injector swaps...
:eek:

Glad you enjoyed the infor re Mallet's 99 testing - right now it seems they are running a lot of comparative cam profile testing...
 
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