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Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here. |
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#1
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Timing retard methods
Hey guys I want to run more timing until I see boost would you trust a msd 6 plus to pull timing out? I have a Hobbs switch that would send a signal to the msd box at 3 # of boost and the box can pull up to 10 degrees out , it’s used for nitrous but the box doesn’t know it’s boost . My fear is what if the Hobbs switch fails or the msd box fails and doesn’t pull out the timing . Thanks
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#2
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I have no experience with boost, but I do with timing control. With a box like this: https://www.diyautotune.com/news/int...d-microsquirt/
you could control the timing, and the boost, and with an O2 sensor you could enable spark/fuel cuts for safeties if things go wrong. You don't have to control fuel with it, but you could. ETA: this is a really basic version. But it would be plenty good for full timing control, and safeties, rev limiters, etc. Also it will accept a GM ethanol content sensor, if one was to control fuel with it. Could be handy for the boosted folks
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'65 Tempest 467 3650# 11.30@120.31 Last edited by Scott65; 03-01-2022 at 12:12 PM. Reason: Addition |
#3
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That would scare me personally. If the switch fails or the box fails to pull timing you likely will tear something up. I had a similar thing happen with the Hobbs switch to my meth injection system and melted a few pistons when it malfunctioned. I have ran megasquirt boxes to control timing like Scott mentioned on a few cars with good success. I have a couple msd boost timing master boxes I have acquired but they kind of scare me if they don’t function properly so I haven’t tried one yet. Their is also a company called progression ignition that makes a pretty cool looking distributor that you can program. I have not tried one but have thought about it for a simple turbo street car.
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#4
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Are you running fuel injection or carb?
For carb I ran the MSD 6AL-2 programmable for a while and it can pull up to 25 degrees. It’s a nice box and has many other features such as start retard, step retard, etc. all setup on a PC using the MSD software. For fuel injection, I would go with a quality ECU that can do what you need such as Holley or Megasquirt. |
The Following User Says Thank You to ID67goat For This Useful Post: | ||
#5
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I use a msd btm for my blower, Works off of vacume and a dial
for more retard as the boost goes up. The dial has 3-settings. GT |
#6
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Boost retard
Thanks guys I am running a Fitech fuel injection system like the Holley sniper ,I guess there is no real safe way then because any device can fail , I guess I keep
It locked out at 28 degrees at all times …. |
#7
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That's the value of the controllers/ECU's with safeties. They can even pull timing when you haven't yet recognized that you need to... (High IAT's, AFR outside of commanded, etc.
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'65 Tempest 467 3650# 11.30@120.31 |
#8
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Quote:
That will allow u to control your timing from start to finish based on boost.. also has fail safes! After all, this is a hobby, take it on as one and always push to make it better...that's 90% of the fun. |
#9
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Quote:
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#10
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I would suggest looking for some training and tuning it yourself..
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#11
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This!
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'71 Holden HQ Monaro - 3850lbs race weight, 400c/i - 11.4 @ 120 '66 Pontiac GTO - 389, 4 speed street cruiser |
#12
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Anyone use the multi step retard function of the MSD 7AL-3 box for taking timing out? I was thinking of adding the Boost Timing Master but it seems my 7AL should do it? Only thing I like about the Boost Timing Master is that it operates off vacuum. Does it change timing progressively through the boost curve?
Sent from my iPhone using Tapatalk |
#13
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On H-Os turbo kits,we used the 68 firebird push/pull vacuum control. simple, mechanical, reliable, although we maxed out the boost to 8psi I have used the MSD BTM and it works great and is simple. It is dash adjustible for 1, 2, 3 degrees of retard per LB. of boost.
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
#14
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Utilize that FiTech you've already got! If you run locked out at 28* and you're not having issues at your current boost pressure, you already have a known safe baseline. You can road tune around that fairly easily.
If I recall correctly, your combination is something like a 6x8 head with a FiTech 1200pa on E-85 and no intercooler? How much boost do you run? I'd start first at your 45 kPa MAP settings and start adding in the type of timing those heads will typically want to see. Probably somewhere between 34-36 degrees. Even at 95 kPa, you're not yet seeing much if any boost pressure. The FiTech will allow you to then command a certain amount of retard per pound of boost. You have to convert kPa to psi for this. Without changing the breakpoints in the system, it gives you 180kPA setting, which is equal to about 12psi. the FiTech will interpolate based on that figure. So as an example if you wanted to pull 1* of timing per pound of boost You'd use something like this. 36-12=24*. The system will then interpolate actual timing figures linearly based on MAP. If you run 28* and 7 psi right now (I'm guessing), and your head wants 36 total, that's 1.14* per pound of boost. You'd enter around 22.32* for your 180kPa MAP setting and at 7psi you'd see 28* of timing as you do now. If you want more granular control, you can get into the ProCal software and change your break point for the boost map to around 150.00. Every 1 psi over 100 kPa is roughly equivalent to 6.9 kPa. At that point it's about making small increases upwards until you start pinging, then backing it off. With e85, you may find that you don't need to pull 1.14* per psi. You might find with that fuel that you only need to pull about half a degree per psi. While the FiTech system does have a built in spark controller, when dealing with boost, you will want to piggy back off of an amplification box like your MSD6 plus. You otherwise may end up in a situation where you are blowing out your spark.
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-Jason 1969 Pontiac Firebird |
#15
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I've been told (not experienced though...) that replacing your coil with an IGN1A in a distributor application should have no problem up to 800-900hp if you can set the dwell in your controller properly and to triple check your distributor phasing is right.
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'71 Holden HQ Monaro - 3850lbs race weight, 400c/i - 11.4 @ 120 '66 Pontiac GTO - 389, 4 speed street cruiser |
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