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Old 05-06-2009, 10:54 PM   #1
Back Road Runner
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Default Info: SRS-10 versus SRS2-20 reflash for a IHE tuned car

I figure I'd post this because there really isn't much info floating around.

As it stands now, I'm running a full exhaust, EL headers and 2.5" all the way back. I've played with the intake some and have settled back to stock although I will incorporate a cold air pick up point for it to reduce intake temps. There isn't much to improve as the stock 2.5" piping is perfectly sufficient to support the flow levels of the engine. There really isn't any need for a 3" upgrade. The biggest fault of the stock setup is simply not pulling in cold air.

On my setup I was running I-Speed's SRS-10 flash for a couple weeks. I recently upgraded to the SRS-20 flash. I will cover basic impressions of the SRS-10 versus SRS-20 flashes and will do some logging and post up a road dyno comparison between the two once I get my hands on my bro's Tactrix cable.

Initial Impressions:

I'll start off with just my basic impressions of what feels different between the two flashes. First off, the SRS-10 is a well massaged tune in itself, geared for stock and 87 octane but plenty happy with aftermarket parts. The SRS-20 simply takes more advantage of what can be done with a freer flowing system. In this regard, stock to SRS-10 is a rather noticeable change with a bump in power everywhere and overall smoother and more refined operation. The step from SRS-10 to SRS-20 is less significant. It takes what was already good with the SRS-10 and tweaks upon it to eek out that little bit more.

I'll say that although the SRS-10 tune feels great on a stock setup, it does slightly feel off once a bunch of aftermarket parts are added. You just step further and further away from the optimum as you toss on parts. Relative to stock, this isn't actually bad, but it does become more noticeable when I did step up to the new SRS-20 flash. The SRS-20 with the full exhaust as the SRS-10 did with stock, very refined, feels great.

I think it's somewhat known that the SRS-20 is tuned for 91 octane. Along with the freer flowing system, this allows the tune to be a little bit more aggressive with timing. This became noticeably apparent when I first started driving around with the SRS-20 flash. Even though the change isn't significant, it is noticeable, mainly in the form of a boost in partial throttle torque. There is a little more pep that wasn't previously there before, and I found I ran less throttle for the same output. I wish I could say WOT use felt the same, but that is harder to discern. I can't easily tell a difference between both flashes at WOT, but I expect there will be some minor gains regardless. It's simply more perceivable with partial throttle use because I have muscle memory towards what throttle press equals what output level. If that changes, it becomes quite apparent. This is apparent. When you step to the floor and wind the engine up, you don't really have as direct a way to perceive gains, at least not accurately.

So what does the SRS-20 get you over the SRS-10? At first I would say not a whole lot, at least not in the sense of major gains like stock to the SRS-10 or a major upgrade part like headers or cams. The gains are more subtle,. but they are there. Mainly, you're buying a more aggressive tune, something that puts as much torque down as the engine will safely allow. You get a little more immediacy, a little more spunk, a little more raw power, and the whole thing simply feels well refined.

I need to spend some time with the tune to gauge other aspects. I'll look at some logging and get a road dyno plot to hopefully show some of the difference. I also want to check mileage and general operation to see if there was much of a change. With slightly less pedal effort, I am curious if mileage will bump up a hair because of it. I wouldn't expect anything dramatic, but a 1mpg or so is always welcome.
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Last edited by Back Road Runner; 05-25-2009 at 04:02 PM.
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Old 05-06-2009, 11:29 PM   #2
RaceFaceXC
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keep an eye on gas mileage as best you can, too. advanced timing usually equals better mileage if its not causing other problems.
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Old 05-25-2009, 04:00 PM   #3
Back Road Runner
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Been taking some initial data logging with the SRS-20 flash, not really sure what I should be plotting really, lol. The only notable difference is mainly a much more aggressive timing profile.



The other data is pretty similar. About the only other thing might be a slightly richer air fuel ratio but barely.

Mileage is slightly better for daily use, basically gained back maybe 0.5 mpg. When I did my exhaust, this is basically what I lost, so I got that back. Under heavy driving, I think mileage is slightly worse though. It seems to use up a little more fuel if you're heavy on the car. Differences overall are not major though. Through most of my modding, I haven't noticed much mileage change with the car. The biggest mileage change was the initial change from the stock ECU to the I-Speed SRS-10 flash. That improved consistency a LOT. With stock I saw from 21-27mpg just driving around. After the flash, I haven't seen anything below 23mpg ever and is within 24-25mpg pretty much all the time short auto-x/rally-x days or pure highway use which would see around 23mpg and 26mph respectively, very consistent behavior. With all the mods I played with, this never changed and have seen at most just 0.5mpg swings.

I tried a little road dynoing and got pretty similar results to the SRS-10 flash but a little less smooth torque presentation. This isn't a same day, same location comparison, so it's tough to really directly compare. I'll need to do a same day quick swap set of runs to get a really direct and directly comparable road dyno plot. I'll throw up that when I get it done.

At full throttle, differences aren't all that perceivable. Midrange seems to be slightly stronger, maybe. It's just hard to tell. The bigger noticeable dutt dyno difference is at partial throttle. You just have more torque putzing around then there was before.

Last edited by Back Road Runner; 05-25-2009 at 04:10 PM.
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Old 05-25-2009, 04:02 PM   #4
williaty
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That's some pretty severe knock at ~3500RPM
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Old 05-26-2009, 03:28 AM   #5
Back Road Runner
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Perhaps. I can't say what the ECU is tuned to and how much it has been corrected. This is at the peak torque range. I'll give it a go tomorrow and see what knock correction says. Even with the stock engine and SRS-10 flash, there was around -1.5 to -2.5 degrees in this range. This might be towards -5 degrees at the peak maybe if the graph is assumed to be smooth and even with zero correction. If I add back the correction, assuming degrees removed, on the SRS-10 tune with the bone stock engine, the timing is not smooth as assumed. It does seem to flatten off at least over this range before jumping back up again. Relative to the info I have on the SRS-10 logging, I wouldn't expect a continually rising timing profile but rather one that flattens and holds constant through that range, then rising again. I'm just guessing on old data here though. I'll need to log knock correction tomorrow and see what it shows. It just doesn't seem to be an unusual thing. This is on standard Kwik Trip 92 octane gas.

Here's a comparison way back when my motor was still bone stock with just the SRS-10 flash showing actual timing with knock reduction and what it would be if I put the difference back in.


The dip there doesn't seem to be entirely uncommon, at least not for the I-Speed flashes.

Last edited by Back Road Runner; 05-26-2009 at 03:38 AM.
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