Gen6 2.5i Tuning

Posts specific to the 2.5 litre NA engine

Gen6 2.5i Tuning

Postby tigger73 » Tue Dec 15, 2015 6:03 am

After initially thinking that I could live with the drive of the 2.5i, I decided that if I was going to keep the car longer term I needed to address the "slug-like" performance.

So I did some timed runs and a dyno as a baseline. Stock the car runs 0-100km/hr (0-62mph) in 10.0 seconds flat.

I've also been working with Matt (KiDo Racing) for a tune for the Gen6. He's managed to crack the Hitachi ECU and the other day when he was in town he reflashed it with an updated ECU/transmission tune.

Here's the before/after dyno comparison - red (stock), green (tune)

Image

Power is up overall, however torque is a major improvement across the whole band.

AFR's are sitting around 12 which is nice and safe but means there's a bit more there...

And finally on the road the 0-100 time has dropped over a full second an it now runs 8.9's consistently.
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Re: Gen6 2.5i Tuning

Postby Gen5is » Tue Dec 15, 2015 6:39 pm

Thats awesome, great gains!

Is your car manual or cvt?

edit: nvm, realised they only came in cvt. How did they dyno your car? Manual mode?
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Re: Gen6 2.5i Tuning

Postby tigger73 » Tue Dec 15, 2015 6:51 pm

Yes CVT only in Gen6.... and yes they dyno'd it in manual mode to force it to hold gears.

You'll see the blip on the curves at ~6,000 RPM. That's the gear change as the CVT dumps a bunch of torque through during the shift.

If only you could have continuous gear changes it'd drive so much faster!
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Re: Gen6 2.5i Tuning

Postby Gen5is » Tue Dec 15, 2015 7:28 pm

What do you mean by continuous gear changes?

The cvt is a single "gear" that changes gear ratios according to torque,rpm,speed input seamlessly, where the traditional automatic gear box would require to shift into the next gear to increase speed, momentarily losing acceleration.

I found using a combination of both seemed faster than sticking to one mode. (Although I do need to test this theory because I my butt dyno may be wrong lol)
I shift into "first" gear in manual mode, then let the car roll a little to let the cvt change its ratios or shifting down to first gear as you slow down (eg. stopping for a red light).
Accelerating in first gear to just before peak rpm, roughly 6-7k. Then shift the gear knob over to D engaging automatic mode which then keeps it in the peak rpm range as the cvt does its work to changing the ratios to increase your speed.

But like I said, I've haven't had a chance to test it out properly and time it against purely using auto or manual mode, so I may be completely wrong haha
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Re: Gen6 2.5i Tuning

Postby tigger73 » Tue Dec 15, 2015 7:42 pm

I just mean when the CVT changes gears you get a nice shove so it would be really nice to be able to get access to that kind of power delivery all the time. It has to be there but is being held back/in reserve by the transmission.

My timed runs (using a g-tech satellite based lap timer) were all done in manual mode. I tried a couple in "D" and one in "I" just for comparison but after the tune manual mode was clearly the fastest. Actually you just stick it in manual mode and it will change gears for you at redline ;)
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Re: Gen6 2.5i Tuning

Postby Gen5is » Tue Dec 15, 2015 8:20 pm

I'd probably say that the torque converter is where most of the power is lost. As to the sudden lurch in between gear changes, I wouldn't have a slightest clue as to why it would do that..lol

Also I don't recall my manual mode ever doing that for me. I might try it out tomorrow.
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Re: Gen6 2.5i Tuning

Postby tigger73 » Thu Jan 14, 2016 10:15 pm

OK so time for an update. I caught up with Matt earlier this week for an updated file which included remapped throttle (DBW) and torque maps.

After a number of 35+degC days it finally cooled off today so I went out tonight and got a number of decent runs in. GPS timer agrees with the bum dyno it's definitely smoother... and quicker

0-100 is now dropped another 0.5 sec to average of 8.4sec over 10 runs out/back. So that's a total of 1.6sec off the stock time. For a 2.5 NA I am impressed!!!!

The goal is to find another 0.5sec to get it into the 7's and then I think we'll call it job done. So when Matt is back in town at the end of Feb it's going to get run on a 4WD dyno and get some final tweaks to hopefully find those last few tenths.
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Re: Gen6 2.5i Tuning

Postby tigger73 » Thu Jan 21, 2016 10:40 pm

Had a full exhaust built & fitted today at Exhaust Technology. New high flow headers, high flow cat, 2 1/2" mid-pipe and new Y-pipe. Only bits that were reused were my sports mufflers and tips.

OEM headers:

Image


Custom headers:

Image


New bits:

Image


Old bits:

Image


Definitely a lot more torque low down and really pulls well off the line now. Though it did fail the wife test.... may need to go back to get the noise level dropped back.

Car is going back on the dyno at the end of Feb as well as getting a re-tune so I'll get some more before/after dyno charts.
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Re: Gen6 2.5i Tuning

Postby Clearlight » Thu Feb 11, 2016 2:45 am

Nice thanks for posting ! The longer primary pipes usually help the bottom end torque . They remind me of the pipes fitted
standard to a car many would not be familiar with , the Alfa Romeo Alfasud flat four hatchback .
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Re: Gen6 2.5i Tuning

Postby tigger73 » Fri Feb 12, 2016 8:02 pm

Clearlight wrote:Nice thanks for posting ! The longer primary pipes usually help the bottom end torque . They remind me of the pipes fitted
standard to a car many would not be familiar with , the Alfa Romeo Alfasud flat four hatchback .


Now that you mention it there is a bit of Alfasud in the raspiness of the exhaust. I'm pretty sure this is coming from the headers too :)
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Re: Gen6 2.5i Tuning

Postby west_minist » Sun Feb 21, 2016 9:15 pm

Nice mods. Are the headers produce that can be purchased online?
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Re: Gen6 2.5i Tuning

Postby tigger73 » Mon Feb 22, 2016 6:27 am

west_minist wrote:Nice mods. Are the headers produce that can be purchased online?



No unfortunately they're a custom manufacture set and were built using the car as a jig.

I believe there is a place in the US that will build these to order, however lead times and shipping costs were a factor in my decision to get these fabricated locally.

I am not aware of any place that does an off the shelf header for the FB25 engine. In reality the market is quite small and tuning options is limited to a few guys like yourself and Matt/KiDo.

The exhaust shop that did the work for me is Exhaust Technology in Kings Park, South Australia. They do have a website with a contact form and do ship interstate (not sure about overseas).

Car is getting dyno tuned on Friday to suit the headers/exhaust. Will post up dyno charts and 0-100 times a little after.
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Re: Gen6 2.5i Tuning

Postby west_minist » Mon Feb 22, 2016 6:44 am

It would be nice to see the gains. Maybe raptor can join in. My headers are getting down.
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Re: Gen6 2.5i Tuning

Postby tigger73 » Fri Feb 26, 2016 10:22 pm

Retune done. A lot more torque across the full rev range.

Dyno results below, however rev 2 tune with headers was run with 91 octane and stock was with 95. Even still the tuned version performs quite a bit better.

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