shift light setting

[Scott W]

what's the best setting to use for a shift light on a relatively stock 5.OL? I know its in or around 5800 rpm, but just wanted to check. Some lights take the rpm pill, which one is everyone using?

 

[89MustangGX]

I would probably say around 5000-5100 range, so by the time you shift you are at 5300ish -- which is probably a good starting point for a stock shift point.

 

[Scott W]

wow, that seems pretty low. For the last 10 years (since i owned the car) I usually wait till my needle touches the redline before shifting. I know my tach is off by about 500 rpm at 6000 rpm so I figure I've been shifting in or around 5600.

I forgot about the delay time. I guess It should be set a couple hundred lower to make up for the reaction time after seeing the light appear.

 

[ECU5.0]

the stock cam doesnt make power after 5k.....i think the best shift point would be like 4900 or 5k

 

[5.0guy]

well, what if u have a b-cam?

 

[stangbear427]

Don't know about the B cam. However, for the original thread Q- the stock cam is out of steam by 4500. Don't bother going over 5K, even with the mods in your sig- just wasting your time with the stock grind bumpstick. The N2O may affect that, but I doubt it.

 

[5.0guy]

so, really, u should go by when the cam stops makin power?

 

[stangbear427]

Not exactly. As a general rule of thumb, yes, you should shift around the peak of your powerband, which is largely determined by your cam grind. However, this is not without exception, since it is just as important that you not drop out of your power band completely when you shift. Therefore, when your optimum shift point will occur is actually as much determined by things like your gear ratio as by your cam specs. If your engine really starts pulling around, say 3000rpm for example, and shifting below 5000 will drop you below that (highly unlikely, especially with your 3.73's) and you will have to climb through the bog zone back into the powerband on each shift, than it would be better to shift higher than 4500 (stock cam) even though the power has begun to taper off at that point- if it means you will be strong immediately when you grab the next gear. Conversely, you don't want to shift too high above your power peak either, and have the R's drop into the middle of your powerband on the shift- effectively missing out on half of your powerband; which essencially means you are beating the piss out of your engine and only have slower times too show for it. It's different for every car- plotting out your ultimate shift points are done easiest on a dyno, although there are several other seat of the pants methods that many of our fellow members swear by. With the simple mods in your sig and that cam, you should theoretically have a 1500-6000 rpm powerband; realistically, I'd say more like 2500-5000 or so. I'm really not familiar enough with the alphabet cams to say... just my $.02.

 

[Scott W]

thanks for the replies. I bought my car used many years ago from a mechanic who had originally bought it for his son, an apprentice mechanic. the car had less than 7000 miles on it, but it was quick and would beat any other stock mustang with ease. the only thing I did know about the car was that he had the timing set to 16 degrees and it ran mint. after a tune-up at ford, the car didn't run quite as good.

I'm wondering if maybe he swapped the cam, because my car certainly pulls well above 5000, or at least it feels like it is.

I've got a g-tech, and i'm going to the track soon, so I'm going to vary my shift points and see if there's a difference.

thanks again guys.

 

[stangbear427]

Is that before or after you push the button for the laughing gas? Sounds like you definately have at least a mild cam in there. I'm in a similar situation- I know that someone changed the cam in mine before I bought it but I have no idea what it is. All I know is it pulls like a banshee right to the redline and only has a semi-lopey idle. Too bad the only way to know more is to yank it out!

 

[arbailey]

I agree with Stangbear427. I had my car dyno'd in May and found I was making peak hp between 4600-4800 rpm. Prior to the dyno run, I had been shifting at the track as high as 5800 rpm - 1000 rpm past peak! I can't wait to get back to the track and lower that shift point! I wonder what it will do to my ET.

 

[super302]

Ya, Don't shift any higher than about 5K if your stock, no need to.

 

[CobraWannabe]

Another thing to consider is deciding if you want to make that shift into 4th. Well, in my case anyway. I have 3:73's and shifting into 4th can take a a tenth or 2 off my time, but if I tach out 3rd, I tap the rev limiter which kinda slows me down at the end, but still brings the ET down, but with a low trap speed. I have to determine exactly when it will hit and hit the clutch just before that to get my best times. I haven't perfected it yet, but I will one day.

 

[stangbear427]

That's true- and is also taking it a step farther than I did- by assuming the shifting was going to be done at the track, which complicates things a bit. While what I said is relevent to the track, I was really only referring to shift points for simply getting the most out of your powerband in general. On the track it may mean a few tenths, but where it matters to me- on the street- it can mean the difference between taking the LS1 in the next lane to school or watching him walk away from you. I've really embarrassed many many cars on the highway that should have beaten me easily because I know my powerband like my own skin. Most people don't- and so we all have the potential to run with cars that are inherently faster than ours when we can take advantage of that. This is equally true at the track, but complicated by the fact that sometimes you have to decide whether or not to make that shift into 4th, etc. On the open road this isn't really a factor since you aren't going to run out of road in 1320'. On the other hand, if every shift isn't done perfectly, the time gap will multiply exponencially since there isn't any stop at the end to keep them from really making you look bad (as apposed to just a few tenths slower). At the track, there is somewhat of a "humiliation cap" as a misunderstood powerband (combined with otherwise good driving) probably won't cost you more than a half a second as a loser; whereas on the street, a wrong shift can mean you will never even catch up. Right wrong or otherwise, now we have it from both sides of the fence...

 

[Scott W]

cobrawannabe- I have to shift into 4th in the quarter mile, even then I'm around 5000rpm by the time I end the quarter (thats with crap traction and no nitrous until late 2nd gear. I hit 110mph in the quarter, with my 3:55s, theres no way I can stay in 3rd. Now that I have drag tires, I'm going to run the NOS from the very beginning and I'm going to up my nos jetting from 125 to 150HP - I'm worrined about running out of 4th gear by the end of the quarter. If your talking about an 1/8th mile than thats a different story.

stangbear427 - even without using the nos it feels like my car just keeps pulling - I notice a drop off in power when my needle hits the red line on the stock tach. I know my tach is off by 500rpm at 6000 (I put the 6000 pill in my msd ignition and took the car out. I revved it up several times until I hit the rev-limiter and my stock tach would read 6500 rpm.)
My Idle is a bit lopey, but not bad.

 

[CobraWannabe]

Oh yeah, I forgot about my LOW trap speeds....lol, I only hit 100 at the end.