Topic: changing cams, questions about timing (updated with dyno graph) (Read 24504 times)

danz · « **on:** September 16, 2009, 08:36:59 PM »

i am going to be switching from a medium lift low overlap cam (bisi.......................) to a high lift high overlap cam (colt cam) on my holset A6.

when going from a low overlap medium lift cam, to a big ass NA cam, what can i expect in terms of detonation/possible timing

ie, with a bigger lift/higher overlap cam should i be looking to add, or remove timing from the maps. i assume with the bigger cam it will bleed off more pressure but i just donk know

figured i would ask the homies

98vtec · « **Reply #1 on:** September 16, 2009, 08:51:15 PM »

fucked up tits = no tech answers

danz · « **Reply #2 on:** September 16, 2009, 09:01:51 PM »

Quote from: 98vtec on September 16, 2009, 08:51:15 PM

fucked up tits = no tech answers

good thing i didnt post pics of mine. ahahhaha

its not like you know anyways, SON!

ryan89crx · « **Reply #3 on:** September 16, 2009, 09:20:07 PM »

Why you getting rid of your Bisi cam?

d112crzy · « **Reply #4 on:** September 16, 2009, 09:27:07 PM »

Because bisimoto is a fucking homsexual that doesn't know shit about cam design. At least not for turbo's.

I've tuned a an F22 bisi cam vs a 272 regrind and the 272 did MUCH better.

98vtec · « **Reply #5 on:** September 16, 2009, 09:35:43 PM »

Quote from: d112crzy on September 16, 2009, 09:27:07 PM

Because bisimoto is a fucking homsexual that doesn't know shit about cam design. At least not for turbo's.

I've tuned a an F22 bisi cam vs a 272 regrind and the 272 did MUCH better.

i'd like to see you build one.

d112crzy · « **Reply #6 on:** September 16, 2009, 10:12:55 PM »

Build a cam?

I can design one, if that's what you mean.

chris · « **Reply #7 on:** September 16, 2009, 10:18:22 PM »

The simple answer is just copy crower stuff

danz · « **Reply #8 on:** September 16, 2009, 10:37:46 PM »

ryan, the car wont carry torque for shit. i have a huge NA cam that i might as well try. i would go to speedfactory for a retune but its sooo late in the season its just not financially viable. ill go and visit james next season for a retune

we all know bisi has a small wanker...

how about timing? my plan is to turn down the boost a little, make some WOT passes listening for det and to take it from there. currently running 7.25-6.75 degrees at WOT/22psi according to ectune datalogs.

d112crzy · « **Reply #9 on:** September 16, 2009, 11:51:05 PM »

Depends on the RPM's the motor/turbo are meant for. If you won't be revving much over 7k, then a hi overlap/lift cam will hurt you.

There's lots of other factors too, though.

ryan89crx · « **Reply #10 on:** September 17, 2009, 12:03:24 AM »

Quote from: d112crzy on September 16, 2009, 09:27:07 PM

I've tuned a an F22 bisi cam vs a 272 regrind and the 272 did MUCH better.

really? have any dyno sheets?

Joseph Davis · « **Reply #11 on:** September 17, 2009, 12:04:15 AM »

Listen to the Crower turbo cams beat the ground and tell me that overlap is bad. Turbo cars tend to like NA cams... and turbos also push any given cam's "sweet spot" higher into the RPM range than it exists in NA form. Being able to spin GSRs or ITRs to 9500 rpms with boost is a good example of this.

The caveat to all of this is that if you go super big on the cam then it *appears* to make the car spool later and be peakier. Given how no one apparently adjusts cam positions on the dyno with turbo Hondas, despite *all* D16 really requiring you do so, I'm half confident that a cam like the 59300 could be made to spool like stock and give good gains across the powerband. How big your Colt grind is, and how that shit will go down, I don't know.

Quote from: d112crzy on September 16, 2009, 09:27:07 PM

Because bisimoto is a fucking homsexual that doesn't know shit about cam design. At least not for turbo's.

Yeah, not being able to break 280 whp on a built to the gills Y7 is disheartening. I'd suspect something else if that wasn't a common theme with other's cars.

My dude with the NA F23A1 went from 159 whp 151 wtq (post dyno) to 176 whp 170 wtq and power falling off hard at 6200 (street tuned to set AFRs, needed back on the dyno because the powerband had *shifted*) on a mild Bisi grind. So the guy does know what he's doing on some level, he just knows dick about boost.

d112crzy · « **Reply #12 on:** September 17, 2009, 12:07:07 AM »

On some level. I've seen good shit with his NA cams, not so much on any of his turbo grinds.

and no, no butt dyno's. Most tunes I do hardly ever end up on the dyno. If they do, they're usually the NA type.

danz · « **Reply #13 on:** September 17, 2009, 03:57:34 AM »

a little more info on the setup, current powerband with the HE351CW Holset and the Bisi 1.22 grind is peat torque/boost at 5400rpm, and only taking it to 7800rpm. torque hits 266.6ftlb at 5400 and drops to 215ftlb by 7200 with the bisi cam im running now.

best mph so far is 118mph, best et 11.793. car weighs 2200 w/ me in it. ectune

head is stock except for a port match on the z6 intake manifold

jd, advertised specs for the cam, its branded as a tri-flow cam, one valve opens at a different time on intake to create swirl i assume

duration at .50, advance, valve lift primary: 198deg, 278deg, .391
duration at .50, advance, valve lift secondary: 193deg, 264deg, .381
duration at .50, advance, valve lift exh: 196deg, 267deg, .404

oh, cam retarded 2degrees on the dyno by james, it helped carry the torque a little but nothing to write home about

Joseph Davis · « **Reply #14 on:** September 17, 2009, 07:27:01 AM »

Can you get a picture of the dyno graph?

danz · « **Reply #15 on:** September 17, 2009, 11:49:42 AM »

sure jd

i should have though about posting that pic in the OP before i opened this thread at work today... LOL

Joseph Davis · « **Reply #16 on:** September 17, 2009, 11:58:42 AM »

I'd have retarded the cam a little more. A lot of guys don't like to with an un-clayed motor, but if you have a Vitara/stock length rod combo I wouldn't worry about it.

danz · « **Reply #17 on:** September 17, 2009, 12:57:30 PM »

8.5 SRP's in an D16A6, w/ A6 head.

this thing has a hard time pulling -20inhg as it is. hah

when i switch the cam, ill start with the same timing values i have now, and start to add some if i dont hear any det/see aluminum on the plugs

from everything ive read the bigger cam should bleed off pressure and allow me to run more timing as is.

Joseph Davis · « **Reply #18 on:** September 17, 2009, 01:40:55 PM »

Idle vacuum is irrelevant. 2JZs with cams can idle -6 to -8 in/Hg, LS with 404s are usually -10 in/Hg. Crower 2 turbo -15 to -18 in/Hg. It's just the load you tune the idle at, nothing more.

Nothing's bleeding off, as IM pressure vs drive pressure ratio is about the same as a NA motor.

dvst8r · « **Reply #19 on:** September 17, 2009, 02:18:10 PM »

I would have put some c16 in that bitch, and leaned on that holset a lot harder. ;D

danz · « **Reply #20 on:** September 17, 2009, 03:00:45 PM »

Quote from: dvst8r on September 17, 2009, 02:18:10 PM

I would have put some c16 in that bitch, and leaned on that holset a lot harder. ;D

that is already at 24psi, kinda disappointing

. its either the head or the cam... going to try out a new cam and then swap to a Y8 head for next year

dvst8r · « **Reply #21 on:** September 17, 2009, 03:46:45 PM »

Quote from: danz on September 17, 2009, 03:00:45 PM

Quote from: dvst8r on September 17, 2009, 02:18:10 PM
I would have put some c16 in that bitch, and leaned on that holset a lot harder. ;D
...and then swap to a Y8 head for next year

I may have one of those available shortly, I just put the rod through the block of my DD. I still have to pull it apart and see if the head is any good, or if it was smashed.

d112crzy · « **Reply #22 on:** September 17, 2009, 08:13:21 PM »

I'd stick to the z6 head and do some work to it, plus change the cam. valve job + some port massaging should be able to rev that bitch out.

Minor Threat · « **Reply #23 on:** September 17, 2009, 08:29:25 PM »

Dyno graph looks about like the first and last Bisi turbo grind I touched.

d112crzy · « **Reply #24 on:** September 17, 2009, 08:36:31 PM »

What's the rest of the setup consist of?

Minor Threat · « **Reply #25 on:** September 17, 2009, 08:41:53 PM »

Quote from: d112crzy on September 17, 2009, 08:36:31 PM

What's the rest of the setup consist of?

Big everything, made power to 8400rpm with the old stock cam.

d112crzy · « **Reply #26 on:** September 17, 2009, 09:12:09 PM »

meant the op.

Joseph Davis · « **Reply #27 on:** September 17, 2009, 09:39:24 PM »

There's nothing wrong with Z6 heads. Y8 heads are the worst head for forced induction unless you kill off the quench.

danz · « **Reply #28 on:** September 17, 2009, 10:28:17 PM »

Quote from: d112crzy on September 17, 2009, 08:36:31 PM

What's the rest of the setup consist of?

Holset HE351CW
4inch downpipe to 3inch under axle exhaust, one reasonator
Splog manifold
28x9x2.75 FMIC
2.5inch cold side 2.25inch hot side charge piping
Z6 intake 60mm TB (Z6 intake matched to TB)
Stock port A6 head port matched only
Bisi springs and retainers (these i am 100% happy with)
SRP 8.5:1 pistons
Bisi 1.22 turbo cam w/ adjustable cam gear

i think thats just about it

oh, and boost held solid on the dyno, actually creeped up a little and the torque still fell off!

Joseph Davis · « **Reply #29 on:** September 18, 2009, 03:22:55 AM »

Try more retard. 2 degrees isn't enough to get a factory cam back to stock position after a D's been decked, milled.

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Author Topic: changing cams, questions about timing (updated with dyno graph) (Read 24504 times)

chris