I have been talking to some people and I'd like for those of you who have experience with the vortex to chime in.

I had assumed that along with the 10 curves, the cdi could be programmed to what you wanted. This does not seem to be the case. I was hoping that we could learn more about the curves, but I'm being told that the curves are not published, meaning that the specifics are not known. I had also assumed that you could set your rev limit to your needs. This also seems to be incorrect.

That's it for the assumptions.

Heres what I need to know.

Can we get something custom from Vortex?
Does anyone have the specifics on the different maps?
Do the MSD ignitions provide user with a dynamic choice in mapping, or does it just give you a linear curve?

IN an ideal world, I'd like to advance the heck out of the timing up to about 6k and then start to dynamically taper it off as I go through the rpm curve. At or around 7500 - 8500 I'd like to have the ignition timing to be somewhere around stock and then actually retard the ignition around 9K. I'd like my rev limit to be about 9200.

I know that for some, this seems a little odd, and for some, you may not understand the reasoning behind it. The easiest way to explain this is to give you an example.

Advancing the ignition through the entire curve sounds fantastic. However, advancing the ignition at the top end can actually hurt your output and combustion cycle. If any of you have an older car with an HEI or Point type ignition, try advancing the dist. You'll find that you have great bottom end but that the top end lies down. If you can even get that far, most of the time you will simply detonate to no end. Throw nitrous on top of that and the problem only gets nastier.

I'd like to have a discussion based on what I've presented. I don't care if you disagree, just give us the reasons why you disagree. I realize that there are some things happening out there that are unexplainable, and many of you are trying things that have no scientific or mechanical support.... That's OK. Let's talk about it.

For those of you who race things other than quads, chime in and give us your experience. My years of racing blown alky hydro, Nascar - Roundy round, and IHRA have given me the experience, but obviously we're not dealing with CDI's - well, sort of....

What say you????

 

For me it was nitrous on my 91 EFI mustang. The install weighted heavily on the safety of avoiding any chance of detonation. One thing that suprised me was the spark plug gap being reduced to .035 from the stock .050 to reduce spark blowout. It also said to run premium only. It also had the fuel regulator wide open. They even had a low fuel pressure switch on it. So I can understand your concern with timing at that the higher RPM level....it leaves your opportunity for total destruction wide open.....imagine floating a valve for a second. You also dont want to hit it to early and get a backfire and grenade the head. One very cool feature about the DS is that you have 2 spark plugs so that is in your favor. On the custom CDI .... your going to have to call vortex for that. **Smooth your piston and chamber before you go pushing the button, cost of a head gasket vs kaboom.**

 

Good topic Mike[img]i/expressions/face-icon-small-wink.gif[/img]

My experience is with the MSD. It gives you the most control of your timing curve but gives less overall options compared to the Vortex I would say. It allows you to program the curve from stock ignition timing as the baseline and at what rpm you begin to ramp up advance, how much additional advance over stock and over how many rpms you want it to get to maximum advance. (steep or shallow increase)

It also allows you to program a 2 degree retard that I believe is over 7000 rpm.

The MSD will not accomodate the type of curve you are looking for but it is probably as close as you can get without having a custom curve programmed in a box. There are people out there with the ability to flash these things and reprogram them, I would just make sure it is someone you trust and hold off on additional advance in your curve until a little way above idle so you don't kick back as hard and prematurely take out your sprague.

Btw, I run the MSD but I am not a real fan of it just because of how cumbersome and intrusive the setup is. It also makes no fire until the 4th revolution which always makes the bike start harder.

I would like to know more about your timing curve theories.

Ron

 

BajaX, not to worry... the dome and dish are premo.... No flash point in my motor.


Nut, I do wish that I could have the best of both worlds. I'm being told through the back channels that Vortex can make custom curves. I'm not sure that it's a solid tale, but I'm hoping it is.

I've got to talk to some of my Pismo pals and see what they are doing.

as far as the timing theory, it's not so much theory as much is it's principle. When you advance the timing at the bottom of the RPM ramp, you are essentially beginning the explosion (combustion) early. This give you more power due to the explosion putting more pressure on the piston earlier in it's stroke. Now remember that this is in thousands of a second. As you mover through the RPM curve, the piston is moving faster and creating more pressure ie. - heat. This tends to cause problem after you reach critical mass (for lack of a better term). Obviously more heat means that the potential for pre-ignitions increases. By retarding the ignition through the rpm ramp, you can better control heat by moving the spark back in the stroke, creating less unwanted heat and thus continue to produce optimum power. The more RPM, the more heat and the greater the potential of lost power. Obviously this is OVER SIMPLIFYING the process, but it's easier to discuss. Running our Mags on our boats (two mags, one motor) the same theory applied. A magneto produces more energy at lower RPM's than it does at higher RPM. This helps to control heat during the compression stage of the stroke. Now let me say that this was the technology many years ago. I'm sure that there must have been huge advances in technology and it might not hold true today. The pricipal still applies.

Most people aren't putting these motors on computers and measuring spark energy, EGT's, intake temps etc. etc.

I'd be interested to know what is out there? If there is anyone out there with a custom curve? And without giving up your secrets, lets us in a your setups.

Feel Me?

 

look outside of the atv world. [img]i/expressions/face-icon-small-wink.gif[/img] its already out there

 

My understanding of timing advance is it creates a slingshot effect over TDC that puts more force on the downstroke and encourages more rpm.

What else is going on in there besides heat increase at higher rpm that would make us want to back off the advance? More to the point, if we are not experiencing pre-ignition at high rpm, would there still be benefit in backing off the advance as the rpms increase?

 

Big D. You can have them program your vortex with just about any curve you want. I just got mine back from HPR, and had them reprogram my box. My power curve is set with there standard map. You would need to talk with Eric about the specifics of that curve. I had my rev limit turned up to 10,800. Now the rest of the maps were turn into less timiing maps. So from the power map, the first one is -2, then -4 all the way up to -18degrees. So what does that do me? A couple things. First I now have a good map designed around high comp for all motor. Second, when I get my nitrous tuned in, I will flip the switch and run less timing there to help keep the detp at bay. And third, when I get tearing up the hill, and have settled into top speed, I can reach up, and flip the switch back and retard the timing. It will work out great for both on and off nitrous.

I feel ya, do you feel me? Oh gross, you just feeled me up,lol!

 

[img]i/expressions/face-icon-small-shocked.gif[/img] Now that were done playin graba$$ LOL[img]i/expressions/face-icon-small-happy.gif[/img]

Jed, Did HPR reprogram it for you? How long did it take and much $?

I didnt know you could switch curves on the fly. at top speed are you saying it would pull even harder but retarding the timing. Would it be that noticeable?

 

Nut, the slingshot analogy is good. And you are correct when you question the need to back off the ignition if you are not experiencing pre-det. I was hoping that you would chime in Jed, and you were the guy from Pismo that I was refering to. I have other questions for you.... but that will come.

Nut brings up a good point, and I'd like to tackle his points. Not to provide counter point, but to suggest why backing off the timing curve at the top end would help and not hurt. Remember that we are talking about SMALL fractions of a second here and in that, we're only talking about small changes. With non-pressurized systems such as Carburated intake charges, the fuel is not being forced into the cylinder. Years ago we found that because the mixture was not being pumped in (injected in), there was a catch-up phase that carbs had to overcome as rpms increased. Because they have to overcome this small catch-up phase, advanced timing didn't let the cylinder completely fill. Now again, remember that we're only talking in small instances.... Letting the cylinder fill more completely resulted in a more complete combustion cycle and thus a better yield. When we started using injection systems on our 1471 blowers, we found that timing wasn't as HUGE as an issue. The cylinders had a better rate of fill, and what we could do more with fuel and timing curves changes. We had a much broader band of power and a much more scientific/explainable process to work with.

Cut to our Current DS Motors.....

If we can retard the timing at the top end of of the RPM ramp and let our carbs fill the cylinder a little better, we have essentially created a similar combustion cycle to that which we have at lower RPMs. We have also controlled heat a little better due to a more complete fill of the cylinder.

I know that there are some that are going just the opposite and grabbing even more advance at the bottom holding on to it through out the curve. Obviously this would be even better if we could retard the curve towards the top. Some might feel that it's got way more power and that they have somehow changed the effective timing of the cams. Because he can't feel the best of both worlds with a dynamic spark curve, he'll never feel the difference. I know that he's happy with his results and I think it's great. But where does that leave us??? We all know that the MATH doesn't always yield real world results... and we also know that it's not the calculater that wins races... That said, we have to be able to sensibly produce, recreate and support the process. If we can't we're going to start piling up lot's of aluminum and steel.

Because so many of you are on the verge of building big HP, and as we get closer to the breaking point, we must start to take less chances with snake oils, guesses and "let's see what happens" kind of stuff. With an 11:1 motor running 100 octane... you are not in that much danger. Run that same motor up to 13 or 14:1, with a shot of nitrous, launching at 10k.... then we start to get a little harry. And while many have had success, what happens at the next bump of power. Bigger cams that produce more pressure in the cylinder (ie Super large ramps), bigger shots of nitrous, NITRO etc. etc. This is why I'm having this discussion.... We're are we going from here boys?

Good to hear that my Kentucky connection can build my curve. That makes me VERY HAPPY. [img]i/expressions/face-icon-small-smile.gif[/img]

Jed, I'll PM you and get some details.

NUT, I know that you've got comments..... they can only help. Keep up the discussion.

 

Nut, yes HPR did reprogram it for me. They did send it off to have it done, but thats the way it goes. Eric could fill you in a little better on how his power curve is.

If I was to have a curve exactly how I wanted it, it would have a huge amount of advance on the start, and completely taper to the top, where it would actually be pulling some timing out. Eric did say his map more closely matches the stock map, than any other advance map out there.

Big D, I am out till this afternoon, then I am leaving for the weekend, I will check back in before I leave.

I will tell you guys one thing, I had my second map set at -10 degrees of timing for nitrous. At idle alone, it drops the rpm by over 300rpm. On the button, I had to use ALOT more fuel on the power map. I had to pull fuel to get the bike to run on the -10 setting. I am going to go to -4, so that I can get the benefit of both less timing for nitrous, and less timing on the hill.

I have always enjoyed on thing about the vortex. When riding my wifes bike, and climbing say sand mountain, when she starts to lug in third, I can flip the switch, and it dont do much, but it seems to build more torque, and the tires start to lift. Not like its building speed, but more its maintaining it now. It is the only instance that I noticed a difference in changing maps on all motor. And that was with vortex's power map, then switching to one of there retarded maps.

If I could do it again, the third time, I would have them throw in the stutter start as well somehow.