Electromotive HPV/HPX Users - Please chime in with your configuration

Mike as I recall the last unit I set up and dialed in on a carbed car was done on a dyno, which really didn't take long at all. One thing I did find was that in order to get enough advance in the curve it was necessary to reset the trigger wheel to the trailing edge of the 12th tooth, to "fool' the unit. This allowed it to be dialed in with a bit more advance, which this particular 308 seemed to like. As I recall the settings were in the neighborhood of 12 degrees initial, 16 on the 3000 range, and lastly -2 on the 8000 dial. Each motor reacts to timing differently, depending on what modification have been done. High compression, cams, or dialing in the stock cams to improve top end power all play an important part, as does fuel mixture.
IMO, takeing the time to put the car on "The Rollers" to set up the unit is well worththe effort, as it allows you to optimize the curve to fit the motors parameters.
HTH,
Kermit

 

the owners manual will tell you something like 5 deg at idle and 28 at 5000 but it is not a straight line---
If you look at the 328 owners book it actually has a chart. I used it on my 328 motor/TEC-3 SETUP

0 DEG AT 800RPM
5 @1000
12@1500
20@2000
28@3000
32@4000
30 DEG AT 5000 AND ABOVE

SEE PAGE BELOW FOR DOCUMENTS ON 328

http://ferrari.stevejenkins.com/books/328_tech.pdf

 

Atlantaman

Great info, as I am setting up an advance curve for my 3.2;
Did you experiment with or have any data on adding a bit more advance than stock ( 34 degrees or so)? I don't think with a 9.2 compression that would cause a ping, but may be mistaken. I have seen the Kjet runs the engine pretty lean.

I have data from a qv Digiplex manual, and the 3.2 data you have is similar. Will try to post later. Very interesting - great thread.

Many thanks
Russ

 

As to more advance than that, IMO it would not do much in the way of good, but then it is pretty well up to the individual settup. The one I was refering to in an earlier post was on the 308 belonging to Stewart Chung, so he could tell you exactly what the settings are at simply by looking. The motor he is running has 11 to 1 compresion, and is a 2 valve carbed with the cams moved to improve the top end power a bit without hurting the low, and mid RPM power. The result was a very flat power curve, very driveable car. FWIW, he has had quite a few tricks done to the motor while it was here, but you will have to ask him on just what he wishes to divulge.
More advance does not necessarily mean more power. Simplistically, the idea is to have maximum combustion push onthe piston top as soon as possible after TDC, without detonation. Thats why I mentioned the importance of useing a dyno to tailor individual motors likes and dislikes in this area. Mostimportantly, it is important to err on the lessor side, as slight amounts of knock can sometimes not be heard in the interior, yet over time will do itas damage.
HTH
Kermit

 

Kermit is right about the advance on this i think--if you look at the chart on the link i posted you will see a variety of curves--

at first i was trying to max out at about 36 deg but the car felt mushy and ran just a little rough.. Heading back to the dyno next week and will tinker with it then.

Kermit--do you have a Raytec thermo gun to check header temps? and if so do you get much of a variations between cyls? I am reading about 80 deg differences between some. range is usually from 725-800 deg.(after a 5 mile warm-up)

 

Mike
I've been using an HPX for about 2 years. I run a bit more advance low down than stock (to help the torque curve) but was cautioned by Bill Pound not to exceed 34 degrees @5K (per stock) with the P6 cams.

However, I don't know that the settings from one car to another are very meaningful due to car to car variations (e.g., I now run 44 DCNFs with 36mm venturis).

On the carb'd 2Vs, the (Nart) LM GT4 ran 34 degrees of advance. I've got to believe Enzo (or Chinetti) tuned it for max power and I don't see much point in straying too far from what he's done for you already, but, if you're keen to know, put it on the dyno and see.

On plugs, I run NGK 5s gapped to 35 thou. No issues traffic or track.
HTH
Philip
P.S., timing curve for 4v cars will be very different from 2v

 

Phillip,
I use the Raytek Raynger ST in checking, and if I find that there is a marginal, yet noticeable differance in temps, I check fuel ratio first. The Electromotive unit is a very accurate piece, and in that respect delivers spark accurately, so that variances in timing between cylinders wont tend to have much temperature differance.
The Ngk's you mention are my choice as well, however, if you run more compression, you may very well be happier with .030 gap. There again, a dyno will tell. Ad one item that you hit right is the differances in the motors. The differances in combustion chamber turbulance between the 2 valve and the 4 are considerable, thus causeing a different burn rate. Simply put, more turbulance, faster burn, as the mixtures motion itself assists the flame propigation, or spread. This is where "Tumble and Swirl" ( a term used in building hi output motors) comes in to play. Most american iron still rely on Quench, or squish, caused by an intentional flat spot in the combustion chamber to create turbulance, by squirting the mixture out as the piston reaches TDC. Fine for the RPM that they run. But in the Nanoseconds of the actual burn time at higher RPM's that effect loses out over Tumbling.
HTH, rather than confuse!
Kermit

 

The 2v cars will want more timing than the 4V versions, maybe 4 degree if i had to guess, so be a little careful comparing.