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Last Call Guest on these Group Buy Deal Items from Baja Designs
Levigarrett76
Glass Half Empty
Id love to know how accurate the phone drag programs really are.
My guess is using for back to back not so great because gps accuracy and relying on the little sensor in phone for acceleration? Just takes a little difference in signal etc for throw off results.
My guess is using for back to back not so great because gps accuracy and relying on the little sensor in phone for acceleration? Just takes a little difference in signal etc for throw off results.
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- #63
Yeah that's why I'm trying to stick with the same location and as close to the same scenario as possible.
I went shopping for accelerometers last night, the cheap ones (under $150) don't seem to be any better than the phone other than having higher response rates. Response rate being slow is probably not a big deal.
The next step is $800plus in quality of stuff, not happening.
Making an analog one with paper/plastic/known weight seemed reasonable as that's about free, but at that point the accuracy puts me back to the standards of the phone.
I did download a different app that focuses on maximizing the phone acceleration sensor, going to see what that does. If it gives similar results to the green line from "dragger" app, I'll use it.
I started off thinking it would make sense to target total acceleration via minimizing 0-60 times, now I'm thinking I'll be able to actually target best torque for given RPM by watching the acceleration rates and maximizing those through the 2nd gear pulls.
Levigarrett76
Glass Half Empty
Which truck is this on again?
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- #65
1978 f250 400/e4od
Driving in to work today, I've managed to **** something up. Going to work today, wanted to be hard starting, which is a first. Way low on fuel, put 17.7g into a 19g tank. It was fine on throttle but way lean, 16ish at idle and off the gauge lean on idle circuit with any real rpm. Numbers were normal on the throttle, acting like a decent vacuum leak. Idle way down etc.
Checked when I got here and nothing obvious on the outside, PCV has some oil around it which is odd. Maybe the vac lines are all failing, just cheap silicone ones. I have a hard time believing messing with the dist caused issues, I should've only been ******ing it from where it was and it's always ran pretty good.
Might have sucked some junk from the fuel tank into the carb, maybe the carb gasket tore some more, maybe it's worth doing a compression test.
Miffed
Edit: also guess I need to move my gauges to a better spot. 60mph is 4k rpm, had to lean way over to look more straight at it.
2k rpm is 35mph
2.5k rpm is 40mph
This means I was wildly off with my initial assessments
I'd swear I can hear my brain degrading some days 
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- #66
Welp, fired it up, was running like total ****. Plugged vacuum lines variously, no change. Turned out the idle mix screws a quarter turn, no change. Said **** it and drove home. About 25 minutes into the drive it came back around. Guess it's time for new fuel filters before messing with it to much more. Must've been something lodged in the idle circuit that cleared itself out ran fine and was doing what it was supposed to as it should the rest of the way
ran fine and was doing what it was supposed to as it should the rest of the way
Levigarrett76
Glass Half Empty
Oh joy 
Ummduh
Red Skull
At $150 may as well just buy a draggy
I think I got mine for $175 on sale?
Edit: 170 on sale right now
Dragy GPS Performance Meter
Monitor your Vehicles Performance using Dragy. Measure 0-60mph, 60-130mph, 100-200kmh, 1/4 mile, 1/2 mile performance, and more! Dragy uses high speed GPS satellites to accurately measure your vehicles performance within 1/100th of a second.
dragymotorsports.com
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- #69
Yeah, dang that's the thing right there. Decently economical, and something with a format somebody like me can use.At $150 may as well just buy a draggy
I think I got mine for $175 on sale?
Edit: 170 on sale right now
Dragy GPS Performance Meter
Monitor your Vehicles Performance using Dragy. Measure 0-60mph, 60-130mph, 100-200kmh, 1/4 mile, 1/2 mile performance, and more! Dragy uses high speed GPS satellites to accurately measure your vehicles performance within 1/100th of a second.dragymotorsports.com
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- #70
alright, played around a little bit more. For some reason, was getting ported vacuum from both my carb ports. the side that should've been manifold vacuum was doesn't match the ported side either, something must be blocking it internally.
Re-adjusted the vacuum pot and went back down to 3 ish turns out, dropping the response down to 8ish inches. Put it back onto the intake runner port, T'd into the transmission MAP gauge port
after swapping out the filter, pump is doing a very poor job of keeping it near full. Seems kind of odd, but also makes sense for why it feels to be running out of fuel from time to time, the significant delay from pump to carb when it has to spend time filling the filter first as well. Thinking of trying another pump, if no change then getting rid of this filter and putting it down on the frame rail before the pump instead of after it.
truck is still nice and responsive, would like to get back to messing with the distributor more
Re-adjusted the vacuum pot and went back down to 3 ish turns out, dropping the response down to 8ish inches. Put it back onto the intake runner port, T'd into the transmission MAP gauge port
after swapping out the filter, pump is doing a very poor job of keeping it near full. Seems kind of odd, but also makes sense for why it feels to be running out of fuel from time to time, the significant delay from pump to carb when it has to spend time filling the filter first as well. Thinking of trying another pump, if no change then getting rid of this filter and putting it down on the frame rail before the pump instead of after it.
truck is still nice and responsive, would like to get back to messing with the distributor more
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- #71
I've been thinking about this a bunch, doing a bunch of reading and such. Generally focused on 460 stuff because it's easier to find information for. Read a bunch of stuff from scotty and various opinions, several distributor tech manuals and such to try to get a better feel on this and even managed to find a couple videos on the internet were useful.
Let's try to organize my thoughts a touch, apologies if this doesn't make much sense to anybody else. Or if we already talked about it in this thread
Timing cares about flame speed. Flame speed is dictated by fuel (octane, type, AFR, etc)
Flame speed cares about flame front, head design, piston design, cam timing and all those sorts of things that are unique to any specific engine combination.
That's all obvious stuff. For some reason, it made just a bit more sense, then, that total timing is much more dependent on cylinder bore than anything else. That is to say, if all the design stuff is identical between two engines except the cylinder bore, the larger diameter cylinder bore will want/use/take more total timing because it will take longer for the flame to travel the entire breadth of the chamber before dedicating all it's energy to pushing the piston back down. Which is why the 460 with the 4.36" bore tends to end up with more total timing compared to similar 351/302 with 4.0" bore.
Stroke plays effectively no role. Also, none of that matters because each engine needs to be set for itself
Timing too advanced fights the piston and too ******ed won't make the flame front across the bore in time to make peak cylinder pressure, both of those scenarios will result in lower power.
Do we NEED to find our MBT (i like mean best torque, though max best torque is probably more accurate and some people say min best torque) while operating at our highest VE? i.e. WOT and on a dyno or a track? well, no. If we are running the same fuel in the same engine the timing is going to be the same for that given RPM to make it's MBT even with lower VE and lower throttle plates. No load is a bit more forgiving. Much the same as idle being set by ear and the way the engine increases speed with more timing against closed blades, there's no reason we can't do the same for any RPM.
Realistically, we just want to see what our MBT is for wherever we want to set our RPM cutoff point. The limit of our total timing advance.
knowing that we are going to be away from our MBT for a given VE with reduced timing. A dyno gives us a realized curve, there is some mystery theoretical curve out there (that EFI and computer timing can pretty well do using live feedback loops) that is optimized at all positions.
if the engine is happy at some number like 10* (obviously made up) at 2.5k rpm, 3k rpm AND 3.5k rpm, then there isn't much reason to limit it other than if we want some additional buffer at the expense of power and efficiency. What RPM range does the engine USE the most? where does it actually live and work? target the curve around that.
2* ******ed the MBT advance amount is supposed to be the safe target for total timing. For what I'm doing with this truck, guess there is no real reason to have total timing above the 2.5k rpm mark. Not a particularly high revving motor for street use.
general consensus seems to be to limit the vacuum advance to 10* of sweep, apparently that's what all the electronic stuff does so must not be much benefit to going beyond that. Running the sensitivity high on the vacuum advance also seems to be the hot ticket. That'll take some playing around with and likely the welder again.
incomplete thoughts Guess all that is to say i'm expecting to find 34* total timing for a 4.030" bore with my particular combo at 2500-2750 rpm with 10* vacuum adder with high sensitivity should give the betterest driveability. Playing with springs to have a linear mechanical advance from 1000-2800 rpm and see if base timing (without vac) will start just as good when warm at whatever base timing to then determine how much mechanical advance i need to cut back into the slot.
Let's try to organize my thoughts a touch, apologies if this doesn't make much sense to anybody else. Or if we already talked about it in this thread
Timing cares about flame speed. Flame speed is dictated by fuel (octane, type, AFR, etc)
Flame speed cares about flame front, head design, piston design, cam timing and all those sorts of things that are unique to any specific engine combination.
That's all obvious stuff. For some reason, it made just a bit more sense, then, that total timing is much more dependent on cylinder bore than anything else. That is to say, if all the design stuff is identical between two engines except the cylinder bore, the larger diameter cylinder bore will want/use/take more total timing because it will take longer for the flame to travel the entire breadth of the chamber before dedicating all it's energy to pushing the piston back down. Which is why the 460 with the 4.36" bore tends to end up with more total timing compared to similar 351/302 with 4.0" bore.
Stroke plays effectively no role. Also, none of that matters because each engine needs to be set for itself
Timing too advanced fights the piston and too ******ed won't make the flame front across the bore in time to make peak cylinder pressure, both of those scenarios will result in lower power.
Do we NEED to find our MBT (i like mean best torque, though max best torque is probably more accurate and some people say min best torque) while operating at our highest VE? i.e. WOT and on a dyno or a track? well, no. If we are running the same fuel in the same engine the timing is going to be the same for that given RPM to make it's MBT even with lower VE and lower throttle plates. No load is a bit more forgiving. Much the same as idle being set by ear and the way the engine increases speed with more timing against closed blades, there's no reason we can't do the same for any RPM.
Realistically, we just want to see what our MBT is for wherever we want to set our RPM cutoff point. The limit of our total timing advance.
knowing that we are going to be away from our MBT for a given VE with reduced timing. A dyno gives us a realized curve, there is some mystery theoretical curve out there (that EFI and computer timing can pretty well do using live feedback loops) that is optimized at all positions.
if the engine is happy at some number like 10* (obviously made up) at 2.5k rpm, 3k rpm AND 3.5k rpm, then there isn't much reason to limit it other than if we want some additional buffer at the expense of power and efficiency. What RPM range does the engine USE the most? where does it actually live and work? target the curve around that.
2* ******ed the MBT advance amount is supposed to be the safe target for total timing. For what I'm doing with this truck, guess there is no real reason to have total timing above the 2.5k rpm mark. Not a particularly high revving motor for street use.
general consensus seems to be to limit the vacuum advance to 10* of sweep, apparently that's what all the electronic stuff does so must not be much benefit to going beyond that. Running the sensitivity high on the vacuum advance also seems to be the hot ticket. That'll take some playing around with and likely the welder again.
incomplete thoughts
Guess all that is to say i'm expecting to find 34* total timing for a 4.030" bore with my particular combo at 2500-2750 rpm with 10* vacuum adder with high sensitivity should give the betterest driveability. Playing with springs to have a linear mechanical advance from 1000-2800 rpm and see if base timing (without vac) will start just as good when warm at whatever base timing to then determine how much mechanical advance i need to cut back into the slot.
Levigarrett76
Glass Half Empty
vacuum can for a 75 ford f250 360 from standard will be limited 12* total timing
Working well on my 460
Working well on my 460
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- #74
Alright, did a bunch of playing around with things and stuff. Set base to 15* and took a bunch of measurements
Made my timing curve chart. Vacuum pump hooked up to distributor l made it much easier. This is what I started with
Measured the gap and added more timing marks to the crank figure 38* is a good stopping point
Timing light, hand vac pump, tachometer under hood, vac gauge to manifold, ear muffs helped so that I could run it up to whatever RPM without going deaf
Figured I'd do what I could to limit the vacuum can reach. Wanted it to be adjustable. End up up using a self drilling screw and a small piece of sheet metal
Cleaned up the shaft so I could measure the throw for 20*
Pulled vacuum and made a line for the arm travel
Snipped and trimmed it up a bunch, wanted to fold down along the sides to keep it located and fold up at the end so I could adjust the throw. Did have to cut off the excess hanging to the inside
Adjusted the hex screw full clockwise to get the highest sensitivity, starts moving at about 4"
10 img limit
Made my timing curve chart. Vacuum pump hooked up to distributor l made it much easier. This is what I started with
Measured the gap and added more timing marks to the crank figure 38* is a good stopping point
Timing light, hand vac pump, tachometer under hood, vac gauge to manifold, ear muffs helped so that I could run it up to whatever RPM without going deaf
Figured I'd do what I could to limit the vacuum can reach. Wanted it to be adjustable. End up up using a self drilling screw and a small piece of sheet metal
Cleaned up the shaft so I could measure the throw for 20*
Pulled vacuum and made a line for the arm travel
Snipped and trimmed it up a bunch, wanted to fold down along the sides to keep it located and fold up at the end so I could adjust the throw. Did have to cut off the excess hanging to the inside
Adjusted the hex screw full clockwise to get the highest sensitivity, starts moving at about 4"
10 img limit
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- #75
Wanted to see if I could get more than 15* mechanical, so measured this and subtracted from the stop arm. It's about 10 thou of an inch for each degree of crankshaft timing. Still hate those calipers and still haven't thrown them away, super cheap and low repeatablility.
Ended up at 490", tried to come up short, ended up going long. Oh well, close enough
And I had a flat spot in the curve, so I got rid of the heavier spring. Figured I'd see how just the 1 lighter spring did
And here's my after with 11* base for 35* total, this was after a bit of futzing with it variously. Originally was trying to get the slot to give me 22* mechanical advance, ended up with 24*. Got the vacuum pot to give me 20* with as low as it would go, nice that it's adjustable. With the full 31* base timing at idle, it is pulling 20" of vacuum at 800 rpm, seems happy
Moved my AFR and Tach up to where they can be seen and put the vac gauge closerish. Went for a drive
Aaaand it's lean. Way lean, dang near all over idle circuit is fine, seems to have picked up some junk in the primary circuit. Going to need to clean up the carb then it'll be time to see if it works or not
Ended up at 490", tried to come up short, ended up going long. Oh well, close enough
And I had a flat spot in the curve, so I got rid of the heavier spring. Figured I'd see how just the 1 lighter spring did
And here's my after with 11* base for 35* total, this was after a bit of futzing with it variously. Originally was trying to get the slot to give me 22* mechanical advance, ended up with 24*. Got the vacuum pot to give me 20* with as low as it would go, nice that it's adjustable. With the full 31* base timing at idle, it is pulling 20" of vacuum at 800 rpm, seems happy
Moved my AFR and Tach up to where they can be seen and put the vac gauge closerish. Went for a drive
Aaaand it's lean. Way lean, dang near all over
idle circuit is fine, seems to have picked up some junk in the primary circuit. Going to need to clean up the carb then it'll be time to see if it works or not
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- #77
Playing around with the computer to make a graph This is what I had wanted to end at, but didn't
[edit:
https://www.holley.com/support/set_your_timing/ looking at the holley link below it seems my chart here is extremely near their expected curve for the 1 silver & 1 blue spring setup (pretty common) with a silver pin (25*). Interestingly, it has the same sort of swell/bump that i've got about 1700 rpm, maybe i'll leave it be and call the dist settled)
currently sitting at 8* base to see if that would help my lean condition (it's actually a fuel problem or some such)
and here is what i'd started with playing around with
and here is what I had been driving around all this past week with
alright, well that's fun. Helps illustrate what the gain was by going to just the 1 light spring. Does look like I can "smooth" out my current curve (the top charts) if I tighten up the anchors a little bit (add preload to the spring)
edit: added the timing chart xls as an attachment to this post
This is what I had wanted to end at, but didn't[edit:
https://www.holley.com/support/set_your_timing/ looking at the holley link below it seems my chart here is extremely near their expected curve for the 1 silver & 1 blue spring setup (pretty common) with a silver pin (25*). Interestingly, it has the same sort of swell/bump that i've got about 1700 rpm, maybe i'll leave it be and call the dist settled)
currently sitting at 8* base to see if that would help my lean condition (it's actually a fuel problem or some such)
and here is what i'd started with playing around with
and here is what I had been driving around all this past week with
alright, well that's fun. Helps illustrate what the gain was by going to just the 1 light spring. Does look like I can "smooth" out my current curve (the top charts) if I tighten up the anchors a little bit (add preload to the spring)
edit: added the timing chart xls as an attachment to this post
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Provience
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- #79
Unplugged the vacuum advance, which popped off aggressively thus sending my hand into the fan
Next time I'll try to remember not to do that with the engine on and at high idle.
But it did help dramatically. Now it doesn't make a rattle until 2300 rpm and I can start playing around with the vacuum advance degree limiter. Probably see if I can get it down to 15*, see what that does and then 10* if it'll clean up.
For the top end of the curve, only really option is to add spring. Free option is to increase preload and see if that will move up. Slightly more expensive option is to buy a spring multi pack.
Don't want to go back to the heavy spring if I can avoid it.
It's tough to say if this has eliminated the tip in bog. It seems to have, need to see where I can get the top of the curve to clean up before really digging into it.
Next time I'll try to remember not to do that with the engine on and at high idle.
But it did help dramatically. Now it doesn't make a rattle until 2300 rpm and I can start playing around with the vacuum advance degree limiter. Probably see if I can get it down to 15*, see what that does and then 10* if it'll clean up.
For the top end of the curve, only really option is to add spring. Free option is to increase preload and see if that will move up. Slightly more expensive option is to buy a spring multi pack.
Don't want to go back to the heavy spring if I can avoid it.
It's tough to say if this has eliminated the tip in bog. It seems to have, need to see where I can get the top of the curve to clean up before really digging into it.
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Provience
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- #80
Alright, with a screw driver and pliers I was able to bend the tab down and getting just shy of 10* vac advance. Not the most precise way to do things, but in the parking lot you get what you get. Curious if this will get me no noise up to the current 2300 rpm limit.
Will edit tonight with results
Edit: no issues with 10* vacuum. Tossed a screwdriver in the truck so I can play with 15* before settling on probably the 12* recommend above from Levigarrett76
edit2:
these charts are kind of fun to play with, going back and forth between them to see what's what. the only difference between THIS setup and when i had the vac advance disconnected, with throttle open enough to have 6" on the vac gauge I can get into rattle at 2100 rpm. ease off the throttle and then the 2300 rpm remains. AFR doesn't matter, tried the other tank that should be cleaner with no change as well. Going to put some high octane pump gas into 1 tank tomorrow as it's nearly empty, then I can play with the difference between the octanes as well and see what that gives me.
Spring kit should be here tomorrow evening, see about stretching the curve at that point. Figure i'll stick with the same "factory light" spring and add whatever the lighter spring is. See what that does and still have the aftermarket medium and heavy springs afterward
Will edit tonight with results
Edit: no issues with 10* vacuum. Tossed a screwdriver in the truck so I can play with 15* before settling on probably the 12* recommend above from Levigarrett76
edit2:
these charts are kind of fun to play with, going back and forth between them to see what's what. the only difference between THIS setup and when i had the vac advance disconnected, with throttle open enough to have 6" on the vac gauge I can get into rattle at 2100 rpm. ease off the throttle and then the 2300 rpm remains. AFR doesn't matter, tried the other tank that should be cleaner with no change as well. Going to put some high octane pump gas into 1 tank tomorrow as it's nearly empty, then I can play with the difference between the octanes as well and see what that gives me.
Spring kit should be here tomorrow evening, see about stretching the curve at that point. Figure i'll stick with the same "factory light" spring and add whatever the lighter spring is. See what that does and still have the aftermarket medium and heavy springs afterward
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Provience
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- #81
91 octane fuel cleaned up all the issues I was having, so what the heck, made a couple pulls at the test track on the way to work.
2nd gear 0-60
8* base
Bumped it up to 10* base and did get just a little bit of breakup around the top of the curve
Obviously I'm not building this engine for expensive pump gas, so I'll cut the timing to tolerate cheap pump gas. This does help validate that I can run mid or high strength at the pump when towing and I shouldn't have issues.
Charts are tough to read, at 8* base I dropped to .25g at 48 mph, at 10* base it was 36 mph. A little bit less timing on the way up made a noticeable difference in torque
Edit: also noticed that the WOT tip in bog/hesitation is massively reduced, just barely there and not really a seat of the bench feel. Mostly a flash of lean on the AFR and a quick cut sound
2nd gear 0-60
8* base
Bumped it up to 10* base and did get just a little bit of breakup around the top of the curve
Obviously I'm not building this engine for expensive pump gas, so I'll cut the timing to tolerate cheap pump gas. This does help validate that I can run mid or high strength at the pump when towing and I shouldn't have issues.
Charts are tough to read, at 8* base I dropped to .25g at 48 mph, at 10* base it was 36 mph. A little bit less timing on the way up made a noticeable difference in torque
Edit: also noticed that the WOT tip in bog/hesitation is massively reduced, just barely there and not really a seat of the bench feel. Mostly a flash of lean on the AFR and a quick cut sound
Levigarrett76
Glass Half Empty
I took a piece of soft copper tubing and cut it to fit around the advance stop pin in my dizzy, clamped it in place. Reduced the mechanical by about 5-6*. this would probably help your tip-in with more initial?
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- #83
I e got some sort of sleeve already on my advance stop, figured it was factory. That's actually how I ended up so far off on my math and over cutting my slot, it's got a little bit of play to it that I didn't take into account.I took a piece of soft copper tubing and cut it to fit around the advance stop pin in my dizzy, clamped it in place. Reduced the mechanical by about 5-6*. this would probably help your tip-in with more initial?
Going from 8 base to 10 base didn't really make a noticeable difference at the base, or maybe it was just overpowered by the change at mid to top. Laying down/stretching out the curve to get that side cleaned up will let me go back to checking the base after. Being an auto, it's goes through the lower RPMs with the quickness
Levigarrett76
Glass Half Empty
That black bushing is factory. I lost mine like a dumbass
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- #85
It's nice that folks stop and check on you with a good up. Everybody is a mechanic until you say you are recurving your distributor. Old guy problems lots of confused looks.
Allstart gm hei advance curve kit part #81300 for $8. Gold is lightest, then black then silver based on spring feel with fingers
Added the gold, had a bunch of preload in the factory position, so bent the tab up a bunch to get it just collapsed at rest. Really just trying to see if it will lay over the top end a bit.
Probably won't get the timing light on it today to see what's what, will see how it does on the drive home with 91 vs 87 octane fuel. Going to try to remember to catch a 0-60 with the 91 octane to see what changed on the dyno.
Regardless the overdrive transmission is nice, I can make my whole commute comfortably without going above 2k rpm
Edit: quick jaunt down the street, 87 octane fine to 3k rpm, no noise.
lots of confused looks.Allstart gm hei advance curve kit part #81300 for $8. Gold is lightest, then black then silver based on spring feel with fingers
Added the gold, had a bunch of preload in the factory position, so bent the tab up a bunch to get it just collapsed at rest. Really just trying to see if it will lay over the top end a bit.
Probably won't get the timing light on it today to see what's what, will see how it does on the drive home with 91 vs 87 octane fuel. Going to try to remember to catch a 0-60 with the 91 octane to see what changed on the dyno.
Regardless the overdrive transmission is nice, I can make my whole commute comfortably without going above 2k rpm
Edit: quick jaunt down the street, 87 octane fine to 3k rpm, no noise.
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Levigarrett76
Glass Half Empty
That gold looks similar or close to mr gasket 925d.
Thx for being test mule, good to know hei springs will work
Thx for being test mule, good to know hei springs will work
rattle_snake
****wits
The easy way, electrons instead of springs and things. The commanded timing value is displayed on the dash while you drive, so you can correlate the behavior.
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- #89
Fully agree. The full electronic unit is the hot ticket. Really makes it something that could be settled in an afternoon that wayThe easy way, electrons instead of springs and things. The commanded timing value is displayed on the dash while you drive, so you can correlate the behavior.
Levigarrett76
Glass Half Empty
Bu-But white new balances and screw driver?