The 346 went into the 120's also, but fuel pressure was fine. In fact, I honestly expected VE to drop some, because of the factory intake, the cam being rather moderate for a 428, etc. I was thinking that the VE being so high was a result of the pump fading until I timed the 90-122 mph run at 3.4 seconds in fourth. The 346 on my best 1/4 went from 103 to 129 in 3.8 seconds in fourth. It's the only reference I have, but it gives me an idea that the airflows and fuel calcs can't be too far off.

 

I'm expecting to. I was at 490 g/sec and 6% lean (as compared to commanding 12.7:1, not stoic) on the WB, so that alone puts it over 512. The 1.16 g/cyl and still lean (compared to 12.7 commanded as above) just has me floored.

Timing is still conservative also.

 

This car is just awesome man. Props buddy. I want to fly out and go to the track lol

 

agree. im surprised it recovered from horsecock as successfully as it did

 

oh wait i spoke too soon. LMAO

 

Great Progress Jake!
Thats very cool that you can determine over scavenging from
Data Logs. Will that change from 6400-7500 RPM?
Would you reduce exhaust duration or widen LSA, or a
little of both if you were to re-spec your cam? Also do
you think your PCM has a chance to keep up once you
change Heads and add ITBs or will you need to go Holley EFI?
Just trying to learn here. Living Vicariously with yours and
Tyler's results till I get straightened out.
LOL

 

Just curious, how do you estimate HP using g/sec and fuel flow?

According to one of the few WOT logs I've done my 6.2l LS7 shows 435 g/sec, 85.8% duty (42lb LS7 injector) and a little rich at 12.4:1 on the WB.

 

This is a sick nasty build

 

Grams per sec % .75

 

Let me know when you have the HPTuners. I think within 5 or 6 good driving logs, we can get your car behaving. We might want to go through and put the idle settings back to the start up tune Hammer did for you, since that seemed to do better holding idle and at least make the car safe to drive before taking it out on the road.

Yup. That formula works assuming everything is perfect. If you're 12.4 but commanding 12.7, then you are approx 3% rich, so you're overstating airflow by 3%, so you need to subtract 3% for a closer estimate. And it's still only an estimate of flywheel HP and not a substitute for a dyno.

Thanks man! I'm still trying to just get the engine to load up. I either have to go to the top of fourth on the street or I need far better traction. I'm putting the Hoosiers on this weekend to see if I can at least hook in second or third to try to dial in the 6400+ RPM range.

If only there was a half mile long straight section of road with really good pavement surface where I could test this thing out safely.... LOL.

 

Fantastic build! A+++

 

I re-read and realized I didn't answer most of your questions.

The over scavenging will just get worse from 6500 up to 8000. The MAP will just steadily fall. It is not unexpected. It's a stock LS7 intake. I knew it would be a limitation on the build, but they're so cheap and plentiful in the wild, it made it easy to just get the car running.

Right now, I wouldn't change a thing on the cam. It drives pretty good, revs great, makes great power. I can't really take credit for the cam. I had an idea where I wanted it to be, but Phteven at Cam motion recommended differently vs my thoughts, and I went with his instead. I'm very happy with it. If, and I mean IF I decided to change anything, I think with ITB it could tolerate more overlap. But I like the IVC and EVO where they are. Seems like a great match for the displacement and compression I'm running.

I've been paying attention to hammer's threads, and I'm guessing the stock controller will struggle to keep up at some point. M y intent is to go with Lance's controller when I do the ITB. I'll still need the stock ECU to monitor the car so it can smog out.

Hope all that helps...

 

I think I'm misunderstanding the "formula" above.

Is the formula as follows?

HP = (MAF g/sec) x (Inj. Duty %) x .75


I've found another way of calculating HP. Here's the formula I have used:

(MAF g/sec) x 7.93664 = MAF lb/hr
(MAF lb/hr) / (AFR) = Fuel lb/hr
(Fuel lb/hr) / (BSFC) = HP

I know all of this is a guestimate, just curious to see if others have another way of getting a "ball park" HP number.



Thanks,
Cole

 

Its actually just maf g/s divides by 0.75

The formula assumes you're at best AFR. If you do it off of fueling, its injector duty cycle x number of injectors x fuel lbs per hour divided by BSFC

 

I've seen this as well in my 6.2 with the stock LS7 intake where in some of the logs the MAP will start to drop around 6500 from 99.x down to ~97 at 7000 or so. I just figured it was beginning to show up as a "restriction" in the flow. The MAP sensor essentially being a vacuum sensor, I would expect to see some vacuum in the intake at higher RPM.

 

That to me is kind of normal. If air is going to rush into the intake, it has to be under some slight vacuum. But seeing a drop from 99 to 90-94 is a pretty big restriction. I've seen that on other cars and it turned out the air intake tubing was collapsed, blocked, or air filters were plugged, etc. This one is doing it without an inlet tract even.

not unexpected, though. The stock LS7 intake is small, and I knew it would be a limitation on the whole combo, but at the very least, it got the car running vs sitting while I save up for what I want.

Speaking of... there was a thread in the external section about the difference coils can make, so I got a set of coils coming from Pantera EFI after a friend got them and he felt like the car ran better. So, I'll report back on the coils soon enough. I'm hoping that the better spark energy will allow me to open up the plugs for a faster burn.

 

Awesome man! Well executed and it sounds great!
Looking forward to the ITB install as well.

 

I think it is helpful to think of the intake manifold as being pressurized to 1 atmosphere when the throttle plate is wide open.

 

Ideally it should be. I'm losing 6 kpa at WOT. Hence over scavenged

 

Hi Jake, MY guess is that you WILL have a runner MAX Pressure in the ITB manifold of 116+KPA at song on a 100 KPA BARO.

The NSFW report is true with the Port Area between Valve/Air Blade becoming VERY LOW when the ITB's are fitted.
This IS the reason for great Throttle Response, the almost instant runner air mass increase when the "blades" are opened.

Lance