Floorman279

iTrader: (11)

for those tuners out there, in your fully built HCI cars, what has the standard/goal of your map KPA been say from 6000 to 7300ish? c6 cars only

LLLosingit

iTrader: (4)

Can't help you on your question and will delete this if you like but wouldn't KPA be what it is at WOT ?... in other words, You do your WOT tuning and ignore KPA unless you see some sort of problem? It's going to vary from combo to combo and elevation and the type of car or engine has little to do with it. Are you having some kind of problem?

QwkTrip

iTrader: (23)

I have a Mamo H/C/I LS7 in a different chassis (no ram air like the C6). My MAP values were about 3 kPa below barometric with a 4" air intake tube. Built myself a 5" air intake tube with a smooth transition to 4" near throttle body and MAP values were within 1 kPa of barometric. That's with a Nick Williams 102mm cable driven throttle body.

So it's totally possible to have almost no losses.

Floorman279

iTrader: (11)

losing all good man, im always having problems, dropped off my dog at the emergency vet earlier, she will be fine tho.....

but this mamo build that i should actually be getting back here after 70 dyno pulls, not kidding, has final numbers and why i do find them acceptable, im kinda trying to investigate into some reasons why the 427 fbody builds always fall short of c6z numbers. i mean similar builds seem to be 30 or more peak power higher in the c6zs, and almost every c6z build regardless of cam or heads seems to hang up high with ease where all the fbody stroker builds peak and then just drop, also seem to peak earlier than they should as well. mine falls into this group as well. not trying to turn this into well its becuase of this and that and this, but for now specificially comparing how a c6z gulps air in comparison to the fbodies. wasnt sure if c6zs with big air sucking machines were still getting 99-99.5 kpa or what they have been getting to help compare what my fbody is doing. once i have a graph we can talk specifically about my build

Floorman279

iTrader: (11)

is this dyno measured or on street? if dyno just one of the big fans in front?

QwkTrip

iTrader: (23)

Both, and same results either way. My air filter is off to the side in the engine bay in a 3rd gen f-body, not inline with the radiator. One of these days I want to figure out how to get some ram air effect.

QwkTrip

iTrader: (23)

Oh, I see. Ya, I'm in a similar boat with my 3rd gen. I'll never make C6Z power. I've wondered the same thing too.

* One of the big differences is C6Z has access to not just good, but AWESOME headers and exhaust. The exhaust is symmetrical too. That's probably a lot of it right there.

* C6Z has a dry sump oiling system that doubles up as a crank case vacuum pump. I have wet sump conversion. That's what, 10 RWHP right there?

* I think the C6Z trans is more efficient than my F-body T56, but my 12 bolt axle is more efficient than their axle.

* On the road the C6Z ram-air intake is far better than mine.

* I don't know what rear axle ratio you have, but my axle ratio is numerically higher than a stock C6Z so that will drop my HP numbers on the dyno

QwkTrip

iTrader: (23)

Although.... I'm comparing myself to internet dyno numbers I've seen.

Truth is I came within 4Hp of the n/a record on my dyno... with my tires spinning.... through a single 3.5" exhaust

Floorman279

iTrader: (11)

you make many points, im glad im not crazy for my thinking cause you and i are identical in our thoughts.;..wasnt trying to side track cause wanted to keep it engine related but ill stray to argue a little bit.....

the exhaust you are dead *** accurate, the x pipe is damn near where the exhaust starts to cool down which is where it should be. this obviously could benefit in carrying up high

im goona argue the oiling tho, the ls7 still uses the crank pump for pressure, it doesnt pull like a "REAL" dry sump does so it shouldnt be helping power by alleviating pressure, unless im wrong....and if it is aviaid true dry sumps save an estimated 10-12 i think unless the rings are setup for it where you really see its value

first im hearing about the trans.......also find it hard to beleive the 12 bolt is more efficiant but i dont know where the c6 pinion sits

the ram air is where im thinking the fbody falls short as well.....yea it pulls a lot of air into it but does that charge slow down as it goes almost vertical the redirected by the lid into the TB, where the z06 air has a much better straight shot? this is something id like to look into in the future which is where i mention map numbers

yup i saw many threads where gear change alone on same rear has avg 5 hp loss, and seen quite a few threads in my research where a few claimed no loss in rear swap, but quite a few s60 guys going from 10 bolt 3.42 to s60 4.10s have lost double digit hp and 15 or more tq......however, the c6s have larger wheels in comparison to tiny fbody 17s. thats one spot the fbody has a dyno advantage........yea i no dynos are just tools but i wanna use this tool to see how we can get our non z06 vehicles to carry better

QwkTrip

iTrader: (23)

You jogged my memory and I do remember seeing a magazine test with comparison of LS7 dry sump vs. wet sump with Improved Racing crank scraper, and the wet sump made more power. I have a Holley 302-1 pan with Improved Racing crank scraper (I hand fitted myself), baffles, and traps doors.

I also have the ATI 10% under drive damper that is so popular with the C6Z crowd. Engine wise I've got the stuff. It's everything supporting the engine that's different.

Floorman279

iTrader: (11)

i went the opposite and went with the standard drive pulley but heavier than stock ATI.....the ati salesman told me he is a firm believer in heavy pulleys making more power than lighter ones because the heavier pulley controls harmonocs better than a lighter pulley.....it does make sense i mean, running a lighter fbody pulley on a 427 doesnt make sense.....u would be running a pulley that was a lightweight 346 pulley on a 427 that obviously would create more harmonics, which would be like running a super light weight pulley. i asked him why do you guys make the lighter ones then, his response was becuase they sell

QwkTrip

iTrader: (23)

Yes, being conservative with damper helps with vibration.

I did 10% under drive because I wanted to slow down the power steering pump. F-body pump shaft speed ratings are 7000 rpm continuous and 7500 rpm intermittent. My damper has stiffer rubbers than catalog F-body damper. I will have to replace the rubbers more frequently though than if I used a larger damper.

Floorman279

iTrader: (11)

any idea if the new turn one pumps raised this up....if so im good

QwkTrip

iTrader: (23)

Yes, I also have a Turn One pump and those are the numbers that they gave me.

I can't remember the pulley drive ratio off the top of my head. I just got a rough measurement with a tape measure and did some napkin math. Perfect measurement would use a diameter over pins. If you have a pins kit in your garage then that's very cool but weird at the same time.

Floorman279

iTrader: (11)

nope u got me

Double06

I think the driveline efficiency is a big part of your delta and what is the air temp that the car is taking in. Did they test yours with the hood up/down etc. I know on the C6 a lot of guys are running some sort of a cold air intake and it is usually within 10 degrees of ambient air. I know on my Halltech with the Beehive it is about 10 degrees delta with my hood closed. Every 10 degrees is 1% in power difference. Not sure what your intake looks like if they did dyno with hood open - which - then that takes care of that issue. The Z06 has a dual 3 inch exhaust and the bend over the axle is very gradual ( like two 45 degree bends and a dip) and dumps into the muffler at about the 110 degree mark over the axle. In other words most cars have a complete U over the axle the Corvette the muffler is part of the U. Don't under estimate a bad exhaust and how it can ruin power. In 1990 ( I had and still have BBC Chevelle) I went from 12.30 to 11.65 and 113 to 118 (probably gaining 60 hp in process) converting to a 3 inch mandrel exhaust from a 2.5 inch crinkle bend (you remember those they put a 2.5 inch tube in the parts store/muffler shop tube bender and you end up with a 2 inch crinkle bent pipe - back then that's what we had). The mufflers changed of course which was huge because the casing was way bigger in the 3 inch system. Not sure what muffler you have but most Corvette guys the 2 mufflers are a straight through Corsa etc. Not sure what you have for an exhaust but you could be loosing 10-20 there.

Floorman279

iTrader: (11)

yea the fbodies have little exh options once we lower ourselves.......we did gain after we dropped out exhaust and added estensions, but it was maybe 5. peak didnt carry any better tho.

it was maybe 65-68 degrees humidity under 50.