Shifting at 7800 was foolish - what gave you that idea? Also, you trapped the same at 23psi on pump as you did at 26psi on C16. That makes no sense unless the C16 was just too extreme. It doesn't make sense to use such expensive race fuel when you aren't tuned for it. Yes, the SAFC can be used on top of the flash, but in that case, all you need is a few gallons of 100-104oct mixed in with your pump gas. You should see ~3-4mph gains on the race gas with increased boost. I am not sure if shifting so late could affect the trap speed that much, but it definitely keeps you out of your powerband. It's not just that we are continually losing power from 6500-7800rpm, but that the higher you shift, the higher you are when you hit the next gear. So, your fattest powerband is probably from 5500-6500, but you were spending all your time above the boost taper point from 6500-7800 (est.).

Try shifting at the proper point, and also please clarify what you meant when you said you had boltons and "exhaust cams." There's only one exhaust cam, having it without a MIVEC intake cam doesn't do much, and you didn't list any cam or cams in your mod list later in the thread.

 

he has just the ex. cam

 

clayton what would the proper point be im trying to get my times down right now im at 12.44 @ 111mph at mir with a 1.74 60' just like your honest professinal opinion

 

 

thanks for your explanation.

 

Well, making a wild guess, I'd say to do the 1-2 shift at 6800 or so (or whatever feels right, since you don't have time to really watch the tach), but then do the 2-3 and 3-4 right at 7k-ish. If you have time to get enough runs, then experiment with 7100, 7200, 6900, etc. A cammed Evo (especially 272s and higher) can sometimes get away with 7300-7400 due to the increased top-end, but it really depends on your car, your shifting speed, the track, the conditions, etc etc. I have run great times in my car, but some days are not as good as others despite there being no explanation, so don't fret. Keep trying until you master your car.

No matter what, though, 7800 is ridiculously high. That may be your flashed rev limiter, but no one said you were supposed to rev that high, haha. The best way to figure out where you should shift is by looking at your dyno graph. You want to spend the most time possible in the fattest part of the powerband. For me, that meant switching from 7100rpm shifts at sea level to 6300rpm shifts at 6000' elevation. My powerband shifted down that much...

 

thanks again.
i believe that my car is strong enough
to make 11s .from a 40 miles roll run with my friend sti whith a gt30r i put about 2 cars on him. my car pulls hard, no doubt abut it, i am the idiot that does not how to drive it, haha.
btw; my dyno graph show:

303.4whp@6600 - 7500 rpm

275ftlb@3800 - 5100 rpm

22.5psi




if this was your car, on what rpms do you shift it?

 

Hah, telling us numbers at a certain rpm doesn't help. You have to show the whole graph so that we see the curve. I doubt you are making exactly 303.4whp for 900 rpm - it doesn't work that way.

Also, please do not make the mistake of thinking that your car "pulls hard" based on some highway roll with another car. People do that all the time only to get disappointed by the Regulator (the track). Your trap speed shows your true power, so unless the 7800rpm shifting was really killing you, then the car is not quite as fast as you think. I'm hoping it is, but people put way too much stock in highway rolls.

 

okay clayton thanks most of the time i try to go as close to 8000 as possible but maybe i shoud try to bring that down a lil bit i mean i am runing the comp 280 cams but who knows guess thats what test n tunes are for

 

i have 3 dyno graphs that i like to post but my scanner is acting up. it was on a dyno dinamics.
after a dyno day i did a boost leak test and find a huge leak coming from uicp by a throttle body. the sti dyno 355whp@21psi on pump on the same dyno. we ran about 5 times from a roll and 5 times from a dig and he could not catch me.
i am going to try to post my dyno graps as soon as possible.
thanks for your help.

 

WTF, 8000??????????? Why in the mother loving hell would you do that? I don't know what's going on these days with newbies thinking they are supposed to shift 1000 rpm after the turbo stops making power - that's craziness. Can one of you tell me what is giving you guys these crazy ideas? Yes, 280s make more power higher up, but they are not the sole factor that determine where you shift. The stock turbo starts dying out before 7k rpm and by 8k, it's just blowing hot air. 280s are not fully utilized on the stock turbo, because of how it dies out. 280s are meant for bigger turbos that can still make power at higher rpms.

 

warrtalon have you ever tried and compare what you are saying at the track?
i mean have you done a pass shifting all the way to red line just before fuelcut and done another pass shifting as you say?
thanks

 

Redline is only 7k. I think what you mean is to ask is if I have tried shifting at the rev limiter then shifted closer to redline (7k), right?

What I have done is test all sorts of different RPMs from 6500 up to 7500 in the attempts to find the sweet spot. I already had an educated guess based on my dynographs, but I wanted to see what the difference was. I did it at sea level then again at 6000' here in Colorado. I was optimum at around 7100rpm on STOCK CAMS down at sea level on the 2-3/3-4 shift, but I had to short-shift the 1-2 at around 6500. Not sure why, but my power would always die off quickly after a launch, but if I did a 1st gear roll, power was good to 7500, though that was no help on the drag strip.

Now, at altitude, if I shift at 7k or later, my trap speeds suffer, and my ET is a few tenths slower. If I shift at 6300 or so, it keeps me in the meat of my powerband and gives me my best times. If I didn't know to change my shift points at altitude, I would be much slower than I already am.

 

all of my runs ive shifted at 7400rpms almost before fuel cut i will try your method to see what happens

 

thanks clayton and i have plans for bigger turbo thats why i went with the 280s so.....in plus im goin with alkie next also