Exactly! Maybe the DFI system requires more fuel than the 30 #ers are capable of. I don't know either, but it's quite evident the car made better numbers with the 48's than the 30's. My car made better numbers with the 30's versus the 24's.

Mike

 

Guys,

Ok I may have gotten a little pissy over the comments made, but mostly was just trying to make a point.

I really fail to see the logic, I have been through this 50+ times over on other boards with guys that couldn't tune, build, or test a car for their own lives.

I always return to the common sense logic. Which I try to put out there and hope people can see, and that is very simple.

Why would Jerky's 383 putting out barely 350rwhp off what I can see in the below graphs, not be able to run those numbers or better when Corky and I are easily making over 600fwhp and 500+ ft/lbs with is current setup? That flywheel hp adjusted to his rwhp is close to 500rwhp! That is 150 hp more guys, with ~1/2 the size injectors. No he doesn't run at WOT for gross amounts of time, but neither does Jerky, unless I am missing something. Nor have I yet to see a small injector fail. I have heard all sorts of claims to this happening, but yet to hear any first hand evidence. All the claims have come from conversation like this where people run out of excuses and can't explain the above scenerio. They told Corky and I last year we were WAY out of injector, yet he's making 100+ HP more on the SAME exact injectors this year, off the same fuel lines and pump, turning 1000 more RPM!

I would rather people accuse Corky and I of outright lying about the size injectors we are running than argue the fact that we can't do what we clearly are doing. I mean that is the 3rd straight year he has run his 24#ers on the street and strip. Jerky I will almost guarentee will never see the track time/demand we put our setups through. But I will bet my next 10 paychecks he comes closer to our demand than a WOT run for more than 15 sec at a clip - assuming his car turns quicker than 15sec 1/4 mile runs, which I know it will.

At the end of the day, you can do what you like. I am a person that believes in proven results. Beach Bums 383, Jims 85vet 383, Cork and My 406s, Ralphs 350 (turning 11s), Ralphs 406 hitting low 11s, Corky and my 434 (30#) running mid 10s@127MPH and I how about Hooked ups 421CI motor...with only 30# injectors which I tuned and it still was running PIG PIG rich that day at the strip, I couldn't lower his pressure any more....10.03@133MPH!!!

I find it very hard to believe that these setups listed above are all flukes, they deserve notice and taking into consideration when talking about the injector setup.

If the injectors are too small and causing damage, I would like to know how these setups have survived so long....and further more the question that begs answering even more that EVERYONE avoids when I point out the above:

WHY would Jerky need more injector than the above setups, when every one of these setups are running quicker ETs and making more power than he currently is?

That is the question I would love in just one of these discussions someone would answer. I am not trying to be a PITA with this, but it just bothers me to hell and back that people aurgue with simple logic. I guess all it takes to prove me wrong is to see a setup of equal caliber of the motors above turn better ETs or outperform the above setups. That I am yet to see, and perhaps why I am so convinced the above it 100% accurate.

 

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THE COMP IS 11.5 NO HIGHER NO LOWER WHICH IS ONLY .5 COMP MORE THAN LD85 WHICH TRANSLATES TO LESSTHAN 15HP

 

The reason I mentioned this is that some of the engines I have read are being built with CR of low 10's and even high 9's CR's.

This winter I may take the plunge and swap from the MR to the SR,, I just really wanted to tune on mine some more but have not had much time due to the tranny giving up,, Dynotech told me that my engine should be in the 415-420 RWHP range, but,,,, its all talk till it happens!

 

The DFI should be fully capable of using whatever injectors you have. It won't require a larger or smaller injector, it just needs to be tuned properly for what is in there. Like I said WOT tuning is very easy, and thus he should be able to change the injector constants and go to town, easily getting the same peak power with 24's, 30's, 42's, or 80's.

It's the driveability tuning that'll be harder with the larger injectors, and that can be very complicated and annoying. Wide open throttle though should be very easy, and his tuner should be able to get the same peak numbers regardless. If he's telling him that 350 is all the 30# injectors will support he's very much full of crap, remember I'm pushing 382 with 24's. Now if this was just his baseline with the 30's and he hasn't done any other tuning that's completely understandable.

Just from reading the original post it sounded like he says that's all she wrote, which absolutely isn't the case.

 

Mike,

I'm 100% with you on your statements above. Osh & company have gone way past the extra mile for me in my build and I wouldn't hesitate to recommend them to anyone interested in a fast GM.

I suppose the fact that I know my cam specs indicates that there's no trickery going on here. In fact, all of their cams are advertised plain as day on the site in the catalog section.

Ron

 

As mentioned in one of the previous posts, John (the last tuner) absolutely will not tune a car for ultimate WOT numbers. He will tune to the best numbers SAFELY possible.

If you are going to comment you need to read all the posts. Let me rephrase that... If you are going to throw trash like "he's very much full of crap" around, you need to read all of the posts.

As for the drivability tuning....
What would be interesting to know is if the DFI has the sequential mode option or whether it is using batch mode.

 

He has a Gen7 like yours. I was pretty sure that SFI came standard on the Gen7 -- whether or not that's what they've configured is another question.

Ron

 

Wow, I go away for a day and

The 30lb injectors are running at 80% as set by the DFI

The DFI is not sequential, it's batch. I did not have the extra dough to spring for the new distributor but the wiring is all there and run through the firewall so if I need to I can run it.

Total advance was around 40*. I mentioned that seemed high and John agreed but said that's what the car wanted. He said he has seen that on cars with compression issues. As Steve's car above, I ran quite a while much too rich and may have some ring issues. I was going through a large amount of oil and must have been washing the cylinder walls.

I drove it to work again today and it just runs perfectly. I mean no bad habits or anything and just idles in 90* heat staying around 175*

Ski, my rear is a 4.11 so It'll scoot off the line pretty well.

John Sealock is very picky. He had a guy who used to build data aq equipment for Nuclear Subs build him a high tech data aquisition machine. He actually uses this for A/F based on two bungs on the headers, not tailpipe or other bull. He says the DFI A/F is inaccurate. He monitors the output on his equipment while the car is on the dyno and in the case of the DFI makes the changes to the tables on the laptop with DFI then uploads it. I would go sweep his floors for free every weekend if I could just listen to all the wisdom.

RonRed, I agree they offer stock cams. But their "L98 top end pkg" included a "custom ground cam". I will admit that I was not able to talk to Mike but it just seems I get a hard time about getting what exactly was in the "package".

Steve, if you are looking for a lot, let me know and I'll keep an eye out. I am a builder and just built my own house in Loudoun County. Email me offline.

 

Unreal that he said that about compression/timing. I am EATING oil and running 12* base timing with no pinging at WOT or while lugging on purpose in 6th to test for it.

On the other matter, I will be in touch shortly...

 

Yeah Steve, I am thinking we may have compression issues. I am out of the office for the next couple of weeks. email me @ wannaz06@aol.com

 

Have you ever done a compression test?

My readings had a high of 215 and as low as 195 (on 2 cylinders)

 

IMHO, use the link below W/ .45 BSFC to size your injectors and you will be so close the balance of power will come from tuning... Higher RPM equates to larger injector sizing / due to less time to inject fuel at high RPM, sustained RPM equates to more time @ max duty cycles which can lead to locked & burned injectors.

http://www.rceng.com/technical.htm#WORKSHEET

I averaged your (2) Dyno runs @ 362 RWHP, assumed you were running a manual tans so 15% loss = roughly 417 FWHP

Using the above RC Eng Inj online calculator I entered;
417 BHP (flywheel hp)
8 cylinders
.45 BSFC
80% max FI duty cycle
43.5 fuel pressure
It came back W/ 29.49 LB/HR Inj

If smaller injectors buy you some power during closely controlled repeated tuning sessions, great! Problem is any reputable business would be walking a fine line to suggest small injectors ran at or past the published duty cycle ratings. Doesn't take too many leaned out fuel mixtures to ruin an established business reputation.

And I've had nothing but good experience W/ MORE Performance. Excellent group who have always bent over backwards to help me.

 

I think we all agree that TPIS is a pretty reputable company, and take a look at what they tell their customers....

Pay particular attention to several items....1. The Orange Note to Potential Customers....2. The chart with HP ranges, and 3. The BSFC, at .5 which is pretty high for todays motors.



I find it very funny are basically saying exactly what I am. Mind you, they are the producers of the miniram, which many of you guys are running. And this is their guide to success. Please note that they are saying 42# injectors are good to 680hp, and at a terrible overstated .5 BSFC....and 85% duty cycle.and your recommending them to Jerky who is at ~60% of that power

For those of you who do not know. Brake Specific Fuel Consumption (BSFC) is the measure of a motors efficiency. The lower the number the more capable the motor is of producing equal power with less fuel. Because its more efficient. Therefore taking a rough guess at .45 BSFC using 42# injectors, you would be able to produce 700+ hp with no problem and room to still spare with the 85% margin worked into the chart.

Do you think they are slight overkill on Jerky's motor.

Seems by their comments in orange they are getting tired too of fixing others mistakes of over injecting engines too.

 

Why do you need a new distributor to run in sequential mode?

Ron

 

===============================
Quote from H rocks earlier:
"One of the "BTW" questions I asked was the size of the injectors required on a stroker SR, big cam motor used for road course applications. The instant answer was 30#. The shop I ended up with is a BIG proponent of smaller injectors at higher pressure. Part of the logic was the fact that the engine would be run a significant amount of time at higher RPM."
===============================
Ok ski, can you reduce your psi for a moment to accept your own "exhibit A" above? Who do you think I'm referring to in MY own quote from earlier in this long and winding thread? I'm getting a headache and am going to ........

 

You need a cam position sensor to run sequential. Optispark was created to serve this purpose. The new distributor would have this feature built in and an output for your ECM/PCM

 

Sequential mode require a dual sync distributor. When I got the Gen VII, the sequential mode harness was an Xtra cost option.

From a theoretical standpoint the idea of batch mode always bothered me. (Excessive fuel available to the first cylinder with the last cylinder possibly going lean)

Ski,
I have yet to find or see any two manfacturers agree on what the exact numbers should be to plug into the injector formula. I have seen duty cycle recommendations of 80, 85, and 90. BSFC isn't quite as bad with numbers of 0.40, 0.45, and 0.50 with .045 commonly being accepted for a performance motor. Then to compound the error toss in fwhp. How many people have the actual fwhp numbers? We won't even get into converting rwhp to fwhp (different dynos, driveline loss, etc.)

 

96LT1....

That is exactly my point the injector calculation are WRONG when you just plug in the number. They GROSSLY overstate the size injectors you to use. For our setups we would need 50+ # injectors, can you imagine the fuel that would be dumping in at WOT. You would not be able to trim them back enough to get it to even idle.

TPIS builds, supplies and promotes these TPI cars. Its their specialty, no pun intended. I hardly doubt they would tell the public 40# injectors injectors will support 650+ HP when it wouldn't.

I tend to agee with them on the subject and let the formulas to the geeks, and people that are cluelss and have no past experience to go from.

The only reason I am being long winded on this subject when it comes up. Is SOOO many people are dooped into buying too big of injectors and then have all sorts of problems. Its overkill and causes countless hours and dollars trying to sort out. If it helps one person, then I feel its worth the effort.

 

Ok, so you're telling me who runs 382 rear wheel horsepower and 358 pounds of torque on a daily driver with 24# injectors that I'm wrong wrong. That also means that you're calling Jesse wrong, who is running a much larger motor which makes much more horsepower wrong as well.

My statement is true, if the guy says that 30 pound injectors will only support 350 horsepower he is full of ****, and there are plenty of people here who can prove it.

You are right on one thing, I didn't read the entire thread because people are turning it into a pissing match, which is exactly what you're trying to do with me right now. Get off your damn high horse for just a minute and read what people are saying rather than immediately taking it as an insult.