Bigger FMIC = More Lag
OK here ya go...with the stock intercooler and the mods in my sig:
3rd gear = 20 PSI by 3150
4th gear = 20 PSI by 3000
This was after several pulls in each gear, every pull gave me the exact same result. I did the same thing, WOT from a 2000rpm roll, let off at 20psi and immediately look at the tach.
3rd gear = 20 PSI by 3150
4th gear = 20 PSI by 3000
This was after several pulls in each gear, every pull gave me the exact same result. I did the same thing, WOT from a 2000rpm roll, let off at 20psi and immediately look at the tach.
When I let off the throttle on the 3rd gear pulls, the needle was dead smack in the middle of 3100 and 3200 each and every time, otherwise I would've just rounded up or down to the nearest 100rpm.
Testing spool on the street? Seriously guys? If you want to see what effect changing to a larger aftermarket intercooler has on your power curve, you'll have to be a lot more scientific than that.
- Cars should be compared custom tuned pre IC and custom tuned post IC. Putting an IC on an untuned car and then tuning it will of course decrease spool, especially if you adjust Mivec. That's hardly anything to do with the intercooler.
-Using an eddy current dyno with the same ramp rate and same gear for testing will give you real results. You'll see where torque comes in and can overlay the results.
When the manifold is warm, the spool characteristics are completely repeatable from run to run.
Using this method, I see later spool with a larger FMIC everytime. I've tuned a lot of cars on that dyno and have well over a thousand pulls on it.
The reason I can't believe some of the posts in this thread is that it feels obvious on the street. I think people either aren't comparing fully custom tuned cars before and after or are just fooling themselves.
A larger core will cause the onset of torque to occur later in a tuned car, period.
Now, please don't take any of that to say that I don't think there are huge benefits to larger intercoolers. This is well documented too. There are tests showing lower temperature and less pressure drop. There is proof that the car will retain power better, especially in heat.
I am certain that the small loss in spool time and area under the curve will be more than offset by the benefits the intercooler provides in the areas I mentioned in the above paragraph.
The questions to quantify purchase are: What power level do you begin to see real benefits? What kind of climate do you live in? How do you use your car?
But the thread title, "Bigger IC = more lag" is absolutely true.
- Cars should be compared custom tuned pre IC and custom tuned post IC. Putting an IC on an untuned car and then tuning it will of course decrease spool, especially if you adjust Mivec. That's hardly anything to do with the intercooler.
-Using an eddy current dyno with the same ramp rate and same gear for testing will give you real results. You'll see where torque comes in and can overlay the results.
When the manifold is warm, the spool characteristics are completely repeatable from run to run.
Using this method, I see later spool with a larger FMIC everytime. I've tuned a lot of cars on that dyno and have well over a thousand pulls on it.
The reason I can't believe some of the posts in this thread is that it feels obvious on the street. I think people either aren't comparing fully custom tuned cars before and after or are just fooling themselves.
A larger core will cause the onset of torque to occur later in a tuned car, period.
Now, please don't take any of that to say that I don't think there are huge benefits to larger intercoolers. This is well documented too. There are tests showing lower temperature and less pressure drop. There is proof that the car will retain power better, especially in heat.
I am certain that the small loss in spool time and area under the curve will be more than offset by the benefits the intercooler provides in the areas I mentioned in the above paragraph.
The questions to quantify purchase are: What power level do you begin to see real benefits? What kind of climate do you live in? How do you use your car?
But the thread title, "Bigger IC = more lag" is absolutely true.
Testing spool on the street? Seriously guys? If you want to see what effect changing to a larger aftermarket intercooler has on your power curve, you'll have to be a lot more scientific than that.
- Cars should be compared custom tuned pre IC and custom tuned post IC. Putting an IC on an untuned car and then tuning it will of course decrease spool, especially if you adjust Mivec. That's hardly anything to do with the intercooler.
-Using an eddy current dyno with the same ramp rate and same gear for testing will give you real results. You'll see where torque comes in and can overlay the results.
When the manifold is warm, the spool characteristics are completely repeatable from run to run.
Using this method, I see later spool with a larger FMIC everytime. I've tuned a lot of cars on that dyno and have well over a thousand pulls on it.
The reason I can't believe some of the posts in this thread is that it feels obvious on the street. I think people either aren't comparing fully custom tuned cars before and after or are just fooling themselves.
A larger core will cause the onset of torque to occur later in a tuned car, period.
Now, please don't take any of that to say that I don't think there are huge benefits to larger intercoolers. This is well documented too. There are tests showing lower temperature and less pressure drop. There is proof that the car will retain power better, especially in heat.
I am certain that the small loss in spool time and area under the curve will be more than offset by the benefits the intercooler provides in the areas I mentioned in the above paragraph.
The questions to quantify purchase are: What power level do you begin to see real benefits? What kind of climate do you live in? How do you use your car?
But the thread title, "Bigger IC = more lag" is absolutely true.
- Cars should be compared custom tuned pre IC and custom tuned post IC. Putting an IC on an untuned car and then tuning it will of course decrease spool, especially if you adjust Mivec. That's hardly anything to do with the intercooler.
-Using an eddy current dyno with the same ramp rate and same gear for testing will give you real results. You'll see where torque comes in and can overlay the results.
When the manifold is warm, the spool characteristics are completely repeatable from run to run.
Using this method, I see later spool with a larger FMIC everytime. I've tuned a lot of cars on that dyno and have well over a thousand pulls on it.
The reason I can't believe some of the posts in this thread is that it feels obvious on the street. I think people either aren't comparing fully custom tuned cars before and after or are just fooling themselves.
A larger core will cause the onset of torque to occur later in a tuned car, period.
Now, please don't take any of that to say that I don't think there are huge benefits to larger intercoolers. This is well documented too. There are tests showing lower temperature and less pressure drop. There is proof that the car will retain power better, especially in heat.
I am certain that the small loss in spool time and area under the curve will be more than offset by the benefits the intercooler provides in the areas I mentioned in the above paragraph.
The questions to quantify purchase are: What power level do you begin to see real benefits? What kind of climate do you live in? How do you use your car?
But the thread title, "Bigger IC = more lag" is absolutely true.
I think there just needs to be a bit more definition of the term 'lag'.
Now, say you're on the dyno doing a 4th gear pull, I do no think it is clear cut that the larger volume IC will change where in the rpm range the turbo spools.
Now, what is undisputable is that transient response will be slower, so that 'lag' will be induced. This situation is like being at 4k rpms constant, and then flooring it. It WILL take longer for the setup with the larger IC to get up to boost.
The difference on a dyno is that you can load up the car enough so that transient response is no longer a variable. Furthermore, how the car is loaded up can drastically alter what the boost curve looks like.
For example, I can get 7psi at 2k rpms in 5th gear. Try doing that in 1st gear; not going to happen as there's not enough load on the engine.
Now, say you're on the dyno doing a 4th gear pull, I do no think it is clear cut that the larger volume IC will change where in the rpm range the turbo spools.
Now, what is undisputable is that transient response will be slower, so that 'lag' will be induced. This situation is like being at 4k rpms constant, and then flooring it. It WILL take longer for the setup with the larger IC to get up to boost.
The difference on a dyno is that you can load up the car enough so that transient response is no longer a variable. Furthermore, how the car is loaded up can drastically alter what the boost curve looks like.
For example, I can get 7psi at 2k rpms in 5th gear. Try doing that in 1st gear; not going to happen as there's not enough load on the engine.
I want to keep the stock turbo and upgrade the LICP and UICP. I dont want to buy an oversized FMIC because it seems the cons outweigh the pros. Should I just stick w/ the stock FMIC?
I think bigger FMICs are better for bigger turbos. Right now I stock FMIC is good enough for the stock turbo...also I dont want to loose spool =P. I see ARC makes a FMIC comparable to the stock one but i dont want to spend 2K for that lol.
There has to be a point where the FMIC is too big for the turbo that it becomes unnecessary right? I'd rather spool 200RPM faster than gain 10 more HP...
correct me if I have this all wrong =P
There has to be a point where the FMIC is too big for the turbo that it becomes unnecessary right? I'd rather spool 200RPM faster than gain 10 more HP...
correct me if I have this all wrong =P
understood, but the stock intercooler is made for a stock car, additionally factors such as cooling in the higher rpms comes into play. I do agree that you can have too large of an intercooler, but most of the ones you can get (Stage I) do a good job of cooling and are fairly cheap in price at the expensive of some lag, but you make back up that power through out the power band. I guess it is all in what you want.
Does anyone have a dyno chart showing the loss in spool going to a larger core? Everyone wants to get all technical about it, but then all anyone says is "Yeah it feels like I lost spool."
Don't forget - a lot of the data we may have seen about this is on an VIII or IX where the turbo and intercooler piping are in a different location than the X as well as MIVEC on the exhaust and intake on the X.
My friend and I have identical spools. Both cars are tuned on a dynopack and mine has an intercooler and UICP. I remember this because my friend liked to rub it in that his car spooled the same as mine. I'll see if I can find the dyno sheets with the proof.
BTW, take a look at these I found of HB Speed. Two have a FMIC and two don't. The spools look identical.
https://www.evolutionm.net/forums/ev...-hb-speed.html
https://www.evolutionm.net/forums/ev...fe-my-gsr.html
https://www.evolutionm.net/forums/ev...oes-again.html
https://www.evolutionm.net/forums/ev...-hb-speed.html
My friend and I have identical spools. Both cars are tuned on a dynopack and mine has an intercooler and UICP. I remember this because my friend liked to rub it in that his car spooled the same as mine. I'll see if I can find the dyno sheets with the proof.
BTW, take a look at these I found of HB Speed. Two have a FMIC and two don't. The spools look identical.
https://www.evolutionm.net/forums/ev...-hb-speed.html
https://www.evolutionm.net/forums/ev...fe-my-gsr.html
https://www.evolutionm.net/forums/ev...oes-again.html
https://www.evolutionm.net/forums/ev...-hb-speed.html
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