Where are you setting your Rev Limiter?
01-29-2008, 10:40 AM
#22
4th Gear Member
Join Date: Nov 2007
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Posts: 1,699
RE: Where are you setting your Rev Limiter?
ORIGINAL: Black GT
If shifting at 6600 isn't bad, then why would you want to lower your rev limiter below that? It could become a hindrance, for example, if I'm making peak HP at 6000 rpm and set it at 6500 rpm when I could be safely going higher that that. The point where it would be a hindrance is if I slightly overshoot my shift target of 6000 rpm. Let's say I overshoot by 400 rpm and the timing is already being retarded because I have my rev limiter set at the suggested 6500 rpm (peak power + 500), but I could safely go higher. Wouldn't this cause a greater drop in performance (the added timing retardation) than overshooting the target rpm alone?
I think these are two different issues. You should set your rev limiter to whatever you feel is safe for the engine and you should target your shifting rpm for peak power.
ORIGINAL: modaddict
Well said. You shouldn't ask anybody where to set your rev limiter. Besides the retarding coming into play 200-300 rpm before, it is also a fact for you manual guys that you will never actually shift exactly on your shift point. A good rule of thumb is to try to shift about 300 rpm before the point you really want to shift at. (or set your light there if you have a shift light).
You have to account for reaction time so making it a few hundred rpm before will actually allow you to hit it dead on...
As far as the rev limiter goes, just take a look at your dyno (yet another reason why a dyno is good) and set your rev limiter about 500 rpm past your peak power. So if your dyno says you are making peak power at 6300, then set your rev limiter for 6800 and plan on making your shifts at about 6000 rpm to hit them dead on your 6300 peak.
On this last motor, I held power through 7000 rpm, so my rev limiter was set for 7400 and my shift light was set for 6800 to make the shift on target. This was my set-up. The majority of FI cars I have seen - 6800 for the rev limiter setting and shifting at 6400-6500 is about the norm...
ORIGINAL: howarmat
I have heard that the timing is being retarded anywhere from 200-400 rpms before where you have your limiter set at....so assuming that, you want to set it maybe 500 beyond where your car starts to drop in HP....all setups are very different so unless you have had yours dyno you wont really know where but shifting around 6300-6600 isnt going to be bad really
I have heard that the timing is being retarded anywhere from 200-400 rpms before where you have your limiter set at....so assuming that, you want to set it maybe 500 beyond where your car starts to drop in HP....all setups are very different so unless you have had yours dyno you wont really know where but shifting around 6300-6600 isnt going to be bad really
You have to account for reaction time so making it a few hundred rpm before will actually allow you to hit it dead on...
As far as the rev limiter goes, just take a look at your dyno (yet another reason why a dyno is good) and set your rev limiter about 500 rpm past your peak power. So if your dyno says you are making peak power at 6300, then set your rev limiter for 6800 and plan on making your shifts at about 6000 rpm to hit them dead on your 6300 peak.
On this last motor, I held power through 7000 rpm, so my rev limiter was set for 7400 and my shift light was set for 6800 to make the shift on target. This was my set-up. The majority of FI cars I have seen - 6800 for the rev limiter setting and shifting at 6400-6500 is about the norm...
I think these are two different issues. You should set your rev limiter to whatever you feel is safe for the engine and you should target your shifting rpm for peak power.
Remember that the best mod anyone can ever get is the DRIVER MOD. That is the FIRST place everyone should work on when starting racing IMO.
01-29-2008, 02:31 PM
#23
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Join Date: Sep 2006
Location: Gainesville, FL
Posts: 11,278
RE: Where are you setting your Rev Limiter?
If i'm not power shifting shouldn't I set it exactly where I want to shift, shift light that is?
On the few wot runs I did recording the timing, i didn't notice it be retarded 200-300rpms before the rev limiter. when I get my car back i'll record the rpms and timing at the same time, that should show if it's being retarded.
On the few wot runs I did recording the timing, i didn't notice it be retarded 200-300rpms before the rev limiter. when I get my car back i'll record the rpms and timing at the same time, that should show if it's being retarded.
01-29-2008, 03:20 PM
#24
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Join Date: Nov 2007
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Posts: 1,699
RE: Where are you setting your Rev Limiter?
No - regardless if you powershift or not, there is always some sort of reaction delay. In fact, if you don't powershift, you should leave yourself more rpm room before making your shift...
I am a fairly experienced drag racer and on my full manual auto (no clutch & fast ratchet shifter) my light is set for 200 rpm before my shift point. When I was on the manual - it was set for 300 rpm before.
I am a fairly experienced drag racer and on my full manual auto (no clutch & fast ratchet shifter) my light is set for 200 rpm before my shift point. When I was on the manual - it was set for 300 rpm before.
01-30-2008, 12:09 PM
#25
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Join Date: Mar 2006
Location:
Posts: 1,138
RE: Where are you setting your Rev Limiter?
ORIGINAL: modaddict
You just explained exactly why I was talking about making your shifts 300 rpm or so BEFORE your shift. You should never try to shift at an exact spot cause it can't be done...
Remember that the best mod anyone can ever get is the DRIVER MOD. That is the FIRST place everyone should work on when starting racing IMO.
ORIGINAL: Black GT
If shifting at 6600 isn't bad, then why would you want to lower your rev limiter below that? It could become a hindrance, for example, if I'm making peak HP at 6000 rpm and set it at 6500 rpm when I could be safely going higher that that. The point where it would be a hindrance is if I slightly overshoot my shift target of 6000 rpm. Let's say I overshoot by 400 rpm and the timing is already being retarded because I have my rev limiter set at the suggested 6500 rpm (peak power + 500), but I could safely go higher. Wouldn't this cause a greater drop in performance (the added timing retardation) than overshooting the target rpm alone?
I think these are two different issues. You should set your rev limiter to whatever you feel is safe for the engine and you should target your shifting rpm for peak power.
ORIGINAL: modaddict
Well said. You shouldn't ask anybody where to set your rev limiter. Besides the retarding coming into play 200-300 rpm before, it is also a fact for you manual guys that you will never actually shift exactly on your shift point. A good rule of thumb is to try to shift about 300 rpm before the point you really want to shift at. (or set your light there if you have a shift light).
You have to account for reaction time so making it a few hundred rpm before will actually allow you to hit it dead on...
As far as the rev limiter goes, just take a look at your dyno (yet another reason why a dyno is good) and set your rev limiter about 500 rpm past your peak power. So if your dyno says you are making peak power at 6300, then set your rev limiter for 6800 and plan on making your shifts at about 6000 rpm to hit them dead on your 6300 peak.
On this last motor, I held power through 7000 rpm, so my rev limiter was set for 7400 and my shift light was set for 6800 to make the shift on target. This was my set-up. The majority of FI cars I have seen - 6800 for the rev limiter setting and shifting at 6400-6500 is about the norm...
ORIGINAL: howarmat
I have heard that the timing is being retarded anywhere from 200-400 rpms before where you have your limiter set at....so assuming that, you want to set it maybe 500 beyond where your car starts to drop in HP....all setups are very different so unless you have had yours dyno you wont really know where but shifting around 6300-6600 isnt going to be bad really
I have heard that the timing is being retarded anywhere from 200-400 rpms before where you have your limiter set at....so assuming that, you want to set it maybe 500 beyond where your car starts to drop in HP....all setups are very different so unless you have had yours dyno you wont really know where but shifting around 6300-6600 isnt going to be bad really
You have to account for reaction time so making it a few hundred rpm before will actually allow you to hit it dead on...
As far as the rev limiter goes, just take a look at your dyno (yet another reason why a dyno is good) and set your rev limiter about 500 rpm past your peak power. So if your dyno says you are making peak power at 6300, then set your rev limiter for 6800 and plan on making your shifts at about 6000 rpm to hit them dead on your 6300 peak.
On this last motor, I held power through 7000 rpm, so my rev limiter was set for 7400 and my shift light was set for 6800 to make the shift on target. This was my set-up. The majority of FI cars I have seen - 6800 for the rev limiter setting and shifting at 6400-6500 is about the norm...
I think these are two different issues. You should set your rev limiter to whatever you feel is safe for the engine and you should target your shifting rpm for peak power.
Remember that the best mod anyone can ever get is the DRIVER MOD. That is the FIRST place everyone should work on when starting racing IMO.
In a perfect world...
I think the most important driver mod is the safe driver mod. Having said that, usually on the street you can't safely look at your tach as much as you can at the controlled environment of a track, so that is why I mentioned the potential of overshooting. Unless you can watch your tach continuously like on a dyno, which isn't feasible on the street or track. Although having a shift light like you do would definitely benefit. [sm=smiley20.gif]
01-30-2008, 01:20 PM
#26
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Join Date: Nov 2007
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Posts: 1,699
RE: Where are you setting your Rev Limiter?
With experience comes the ability to shift by 'sound' and 'feel' on the street and not needing to look at your tach...
But I agree that 'safe' is part of the good driver mod.
But I agree that 'safe' is part of the good driver mod.
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