just got back from the dyno... tuning kicks ass!

lcvette · 03-28-2006, 11:27 PM

just got back from tuning the car on the dyno....

have to get a graph and going from memory, but it was a little lower then hoped for but still very very happy with how well the tuning went.. the driveability tunes I ironed out with VE master and all looks excellent, great part throttle and cruise afr's and smooth transition in to wide open throttle.

I think 8 pulls total to shake some knock retard that we worked right on out and the first few were nailing the air fuel across the board to a safe 11.6.

the first run was seeing about 14 degrees of knock retard with the timing locked out at 25 degrees from 4000rpm up and showing an AFR hovering steady around 13. afew strokes of the key got the fuel down where it needed to be and then we attacked the timing until we finally on the last run locked her out to 23 degrees starting early on trying to kill the onset of detonation. the end result was a little less power but zero knock retard on 93 pump which is where we wanted to be.

after a few rides with some fellow junkies pretune there were some optimistic guesses and as fast and hard as the car hit were not wrong to put our estimates higher then what the results were.

from memory the best SAE corrected pull was 438rwhp and 444rwtq available from about 2500 rpm through 5300 where it only slightly tapered off. peak boost was lower then what were were seeing on the street coming in on the dyno right at 7 pounds of boost. post tune the car has lost some of its initial grunt but gained a solid 20 hp and 20 ft/lb's in the midrange where the knock retard was squashing power. it is extremely noticeable here as the pull from midrange to redline has increased considerably. the curves were very smooth with the smoothing set as low as it would go and the AFR is rock steady from onset tip in to redline at 11.6.. a very safe tune. well thought I would share! I am pleased overall with the gains and the way the car feels and look forward to seeing what the track reveals this sunday at Jacksonville!

Chris

drochau · 03-29-2006, 02:26 AM

Congrats! I would say that's an uber-conservative tune, and to be honest I thought you were going to be in the 460 rw range. It's my very humble opinion that you have a little more to gain by bumping the A/F up in the future. 11.6 I would say is safe, maybe a little on the extreme side. I'm running 12.1 with a slight drop to 11.9 in the last 500 rpms (6300-6800). How much timing do you have dialed in at peak torque? (just curious)

Bruce · 03-29-2006, 07:32 AM

Quote:

Originally Posted by drochau

Congrats! I would say that's an uber-conservative tune, and to be honest I thought you were going to be in the 460 rw range. It's my very humble opinion that you have a little more to gain by bumping the A/F up in the future. 11.6 I would say is safe, maybe a little on the extreme side. I'm running 12.1 with a slight drop to 11.9 in the last 500 rpms (6300-6800). How much timing do you have dialed in at peak torque? (just curious)

Remember you are using a FAST system vs stock system is a big different here. With FAST you can target a A/F 12.1 along with WB correction and 2 bar map. With this you are always safe as comparing to factory computer. Just a thought.

438rwhp is on the low side. Should be in the 460-500 range on a 355ci motor with 7psi or so.

Bruce

neat · 03-29-2006, 12:22 PM

Awesome Chris! Glad to see you finally got the tune squared away.

lcvette · 03-29-2006, 12:37 PM

keep in mind the cam in the car is pretty small.. it is a 219/219 TPI cam with 1.5 rockers putting lift at .525/.525 and it is on a 112 LSA.. so power peaks at 5800 according to the dyno, it does not fall on its face after by any means but a nice gradual taper .. torque is very very smooth and no hard spikes just a solid line across the graph. it is conservative and it is on 93 pump with no alky. IAT's were in the 100-117 range throughout the run with a 60* ambient. valves in the heads are also stock. there are a few things that we can do but for now, the car is tuned VERY safe as stated above, and I would prefer for this one to stay running this way while I finish the polo green 355 solid roller car and the turbo CE. n too many projects at once is no good..lol some of them need to stay up and running!

Chris