This last weekend was the first time out with the new engine. Pratically zero prior tuning was done on the engine. At the track I managed to get it to idle and cruise easily enough. I started with the program from the old engine. It's amazing how some changes can change the tuneup so much. 4 degrees more duration on intake and exhaust and the big change of lowering static compression from 11.27 to 9.27 to one. Under initial engine loading the old program proved to be too rich. After wasting my time at the track Saturday, inching the mixture leaner bit by bit, I did some tuning at the shop on Sunday and found that I was just a little bit away from getting the mixture right for up to 138 kPa. That is just about the turn on point for the nitrous. At the shop we did some initial nitrous shot testing on the transbrake and found the mixture it likes. Again, we were close to having that one right too. Next weekend we'll pull the car out in front of the shop and do some launch tests to work on the upper rpm fueling under full load. Fueling in the unboosted regions of the VE table are down about 9 percent of injector pulse width. That can easily be connected to the change in compression ratio. I'm wondering, since I plan on running more boost (28-30 psi) to make up for the lost static compression ratio, will the engine require the same fueling as the old engine that had the higher static compression ratio, but was boost restricted to 22 psi? I'm going to ramp the mixture up at the high boost regions to the same ipw as the old engine to play it safe.
Advanced Engine Theory and Design
- Thread starter Alky V6
- Start date
d90dan said:Don, good seeing you at Barona last weekend. Nice track, no problems hooking up!
It was nice to see the innovation you put into your build. Definitely "out of the box"
Sorry I couldn't put on a better show for you guys. Are you the one that was blasting off 6.60s? Impressive! You guys sure were stirring up the V8 cars. Looked like Dick got his new best? 5.5something or other. Wish I could have socialized with you guys more. It's hard when your trying to tune in a new engine. Next time.
funny video
you guys have to look at this video it takes the double talk up a notch or twenty www.moparaction.com/extra/media/A604.wmv i downloaded it and thought it was something serious and after a few seconds it hit me robby
you guys have to look at this video it takes the double talk up a notch or twenty www.moparaction.com/extra/media/A604.wmv i downloaded it and thought it was something serious and after a few seconds it hit me robby
Well, the engine tuning is coming along. Pre nitrous injection point is tuned to perfection. It's after that where I've been running into a problem. I was getting unexplainable cutting out of the engine. Sometimes just completely dying. The data log was puzzling. I was thinking it was a mixture problem, too rich, so I was trying all kinds of fuel maps to see if I could find the needed curve. Just yesterday it wouldn't even start. Turns out I've been fighting a failing crank sensor. Good grief! :frown:
Schubeck lifters get a no vote. Engine is down being redone. Updating to a better cam thrust system (forward movement). It will be a relatively large needle bearing setup instead of the teflon button I was using before. The drysump and vacuum pump did a good job pulling the crankcase atmosphere down. Left no oil for the cam button and the cam ate its way forward. The lifters started running on the edge of the lobes and we can all imagine the ending to that story. Even so, with the cam movement, I can see a flaw with the lifters. The ceramic wheels want to eat their way out of the lifter body through the side.
KLHAMMETT said:
I already have the new system machined up. It works in concert with the Milodon gear drive I'm using. The forward thrust needle bearing is located close to the cam gear so that it will more easily get splash off oil from the gear drive. The idler gear bearing is already being sprayed by an orifice off the front main bearing passage, so there should be plenty of oil flying around close the the gearset. The old cam button system was located at the nose of the cam in a tunnel cover that replaced the water pump back surface. The tunnel was closed off enough from the gearset that when I removed the front tunnel cover, the debris that had accumulated from the cam moving forward didn't even wash away. It was still in the tunnel. I don't think I had the vacuum pump on the old engine long enough for the wear to become alarming so I didn't catch it during the rebuild. Darn thing is bullet proof now.
- Joined
- May 27, 2001
DonWG said:I'm not going to make it. The cam is a special order and I won't have it in time. I am bummed.
What do you need?
You should pick up a set of the 212lbs injectors!!!!
John Wilde said:
Cam specs are 252/260 @ .050" on 108 centerline. .420" lobe lift. Mechanical roller with an odd fire style nose.
It might be hard to get a good minimum PW at idle with the 212s. It's hard enough with the 160s. I'm at 1.52 ms now. I understand 1.3 ms is the minimum with large injectors.
- Joined
- May 27, 2001
DonWG said:
Who specified the cam?
The centerline is interesting.
I've been going over some datalogs and notes and thought I'd post this note of interest. When running alcohol as a primary fuel and injecting nitrous with alcohol as the extra fueling, you will not net the rated HP of the nitrous system. In fact, it could be less than one half of the rated HP for the nitrous jet size your using. Anticipating this situation, the 200 shot I've been using for turbo spool has worked out perfectly. I've calculated that I'm seeing only 80HP from the nitrous system. That's enough. The rim screws have been yanked pretty hard. It will be interesting to see if the slightly wider lobe separation will make a difference in the nitrous hit. On paper, the less overlap caused be the wider centerlines should keep more of the nitrous from blowing through the chamber into the exhaust.
Guys,
I don't own a Stage II engine now and may never but, as a mechanical engineer, I find this discussion GREAT! Keep up the good work!
Conrad A. Carter, Jr., P.E.
Original owner of 84GN w/ 87 Drivetrain, CAS V1, Champ Iron heads, roller cam, FAST, etc....yeh, I'm hooked big time. Thanks Jack!
I don't own a Stage II engine now and may never but, as a mechanical engineer, I find this discussion GREAT! Keep up the good work!
Conrad A. Carter, Jr., P.E.
Original owner of 84GN w/ 87 Drivetrain, CAS V1, Champ Iron heads, roller cam, FAST, etc....yeh, I'm hooked big time. Thanks Jack!
Actually Conrad, the engine I'm playing with is a stage I configuration. Simple first generation M&A heads with 1.85" intake valves and 1.5" exhaust. That's part of the reason for the long durations I'm running on the cam. It's the only way to flog the performance I want, and desperately needalphaenvirmgt said:
, out of them. The long durations are not recommended for any degree of street driving. It is a drag competition only bump stick. Makes for a very high degree of turbo lag, which is the reason for the nitrous system. The complete system makes for a best of both worlds experience. A cam to give you the maximum top end the engine's valve train can handle and the nitrous, to more than adequately, fill in the bottom and low mid range. In a gas engine, a 50 to 75 shot should be the ticket. It's definitely a hoot and I'm surprised there isn't more playing around with it. Glad to see you enjoy the discussion. I wish more wanted to participate. Gets the grey matter stirred up.
