MSD DIS-4 w/ Electromotive HPV-1 ?
01-13-2002 | 01:02 PM
#1
Thread Starter
Track Day
Joined: Jul 2001
Posts: 19
Likes: 1
From: Rancho Santa Fe, CA
MSD DIS-4 w/ Electromotive HPV-1 ?
Anybody here tried the MSD DIS-4 unit(s) to "pep-up" an ignition set-up like the Electromotive HPV-1 ?
For info on the DIS-4, go here: http://msdignition.com/1disign.htm
The considered application is for a carbed, high compression (9.8:1) twin-plugged 3.2 short-stroke that would run twin Electromotive HPV-1s. If the DIS-4 could be used, I am wondering if one or two of these units would be needed . . . ?
The goal is to achieve much more spark energy (and larger gaps) than provided by the HPV-1s. Another goal is to avoid potential plug fouling that I have read can be a problem with HPV-1 crank-fired motors with carbs.
Another ?: Using premium pump fuel in California does anyone see potential problems with trying to run 10.5:1 compression on the same motor described above?
I am confused by contradicting reports lately. Apparently Andial told a Pelican board member that 9.8:1 is the general limit for street gas even with twin ignition . . . while Steve Weiner's Rennsport site says that 9.7:1 is the limit for pump gas on a single plug application and that 9.8:1 to 10.5:1 should generally not be a problem for twin-plugged motors on premium pump gas.
I understand that compression limits are based on many factors, but what is the consensus on trying to run 10.5:1 compression on street, twin-plugged motors (with carbs and no DME)?
I am trying to formulate a decision of using the Andial/Mahle 98mm piston/cylinder set for 9.8:1 or the set for 10.5:1
TIA!!!
For info on the DIS-4, go here: http://msdignition.com/1disign.htm
The considered application is for a carbed, high compression (9.8:1) twin-plugged 3.2 short-stroke that would run twin Electromotive HPV-1s. If the DIS-4 could be used, I am wondering if one or two of these units would be needed . . . ?
The goal is to achieve much more spark energy (and larger gaps) than provided by the HPV-1s. Another goal is to avoid potential plug fouling that I have read can be a problem with HPV-1 crank-fired motors with carbs.
Another ?: Using premium pump fuel in California does anyone see potential problems with trying to run 10.5:1 compression on the same motor described above?
I am confused by contradicting reports lately. Apparently Andial told a Pelican board member that 9.8:1 is the general limit for street gas even with twin ignition . . . while Steve Weiner's Rennsport site says that 9.7:1 is the limit for pump gas on a single plug application and that 9.8:1 to 10.5:1 should generally not be a problem for twin-plugged motors on premium pump gas.
I understand that compression limits are based on many factors, but what is the consensus on trying to run 10.5:1 compression on street, twin-plugged motors (with carbs and no DME)?
I am trying to formulate a decision of using the Andial/Mahle 98mm piston/cylinder set for 9.8:1 or the set for 10.5:1
TIA!!!
01-13-2002 | 11:44 PM
#2
RL Technical Advisor
Joined: May 2001
Posts: 11,871
Likes: 65
From: Portland Oregon
Hi Kurt:
You may use up to 10.5:1 with twin-ignition on pump premium. You should use unleaded race gas when you go to the track but otherwise you'll be fine.
Regarding your question about the MSD DIS-4's and the HPV-1's,........
From experience, there is no cost benefit and in fact its MORE expensive to go this route, compared to an RSR-converted distributor and a pair of MSD 6AL's.
You would need (6) MSD Coil interface units for all of the HPV-1's coils and a pair of the DIS-4's to do this. Crunch the numbers and you'll see that the RSR distributor, despite the cap & rotor costs, and MSD's/coils is less $$$ overall.
Its much simpler and more reliable in the long run, too.
In many cases, less is more and this is one of them.
You may use up to 10.5:1 with twin-ignition on pump premium. You should use unleaded race gas when you go to the track but otherwise you'll be fine.
Regarding your question about the MSD DIS-4's and the HPV-1's,........
From experience, there is no cost benefit and in fact its MORE expensive to go this route, compared to an RSR-converted distributor and a pair of MSD 6AL's.
You would need (6) MSD Coil interface units for all of the HPV-1's coils and a pair of the DIS-4's to do this. Crunch the numbers and you'll see that the RSR distributor, despite the cap & rotor costs, and MSD's/coils is less $$$ overall.
Its much simpler and more reliable in the long run, too.
In many cases, less is more and this is one of them.
01-14-2002 | 12:37 AM
#3
Race Car
Joined: Jun 2001
Posts: 3,706
Likes: 9
From: Virginia Beach, Va.
Kurt, I'm with Steve on that one...besides, I would see no need to "upgrade" the turnkey benefits of the HPV-1 unit...the coils and everything fit nicely on that gold annodized aluminum mounting plate! ...and yes, it would cost you a bundle of $$$$ to pull that one off.
Plus, being an Electromotive HPV-1 user in the past...I have no idea how one would integrate the input of the HPV-1 setup with the MSD amplifier...we're talking about a high voltage output (capacitive discharge??) on the MSD unit - hooked up to the input of the HPV-1 unit that just requires 12VDC...how will the HPV-1 chip handle that?? It needs a constant supply of 12V, not spiked discharges...man, I just DON'T think that idea will work at all...I just thought of two more reasons BTW.
I didn't mean to come out on top of Steve W., after all, I would consider him the final word...but thinking how one would incorporate the MSD with the Electromotive setup gave me something to ponder.
Anyway, if you work it out, I would LOVE to hear this one, seriously.
The twin-plug distributer with a pair of MSD 6AL units (Steve's suggestion) seems to work well with the acquaintences that I have at the track, one of my friends has that setup on a highly modified 914-6...it's been going strong for years.
On the flip side of the coin, I also have a friend with a highly modified 2.7, 10.5:1 compression I believe, and Webers...he has two Electromotive HPV-1 units and twin plugged heads...he is a constant "contender" at the track, even with my modern-day "twin plugger"!!
We have a lot of fun.
If Steve W. would send me his "ultra-black magic super-duper whammy chip"...maybe this wouldn't be an issue anymore! Hmmmm, maybe I should give him a call.
Plus, being an Electromotive HPV-1 user in the past...I have no idea how one would integrate the input of the HPV-1 setup with the MSD amplifier...we're talking about a high voltage output (capacitive discharge??) on the MSD unit - hooked up to the input of the HPV-1 unit that just requires 12VDC...how will the HPV-1 chip handle that?? It needs a constant supply of 12V, not spiked discharges...man, I just DON'T think that idea will work at all...I just thought of two more reasons BTW.
I didn't mean to come out on top of Steve W., after all, I would consider him the final word...but thinking how one would incorporate the MSD with the Electromotive setup gave me something to ponder.
Anyway, if you work it out, I would LOVE to hear this one, seriously.
The twin-plug distributer with a pair of MSD 6AL units (Steve's suggestion) seems to work well with the acquaintences that I have at the track, one of my friends has that setup on a highly modified 914-6...it's been going strong for years.
On the flip side of the coin, I also have a friend with a highly modified 2.7, 10.5:1 compression I believe, and Webers...he has two Electromotive HPV-1 units and twin plugged heads...he is a constant "contender" at the track, even with my modern-day "twin plugger"!!
We have a lot of fun.If Steve W. would send me his "ultra-black magic super-duper whammy chip"...maybe this wouldn't be an issue anymore! Hmmmm, maybe I should give him a call.
