OFT Review (Vishnu Tuning Tablet first impressions)

[mad_sb]

Originally Posted by phrosty

I'm in same boat. From what I understand, the 2.5" Perrin intake has the same MAF voltages as stock from 4500 on up to be safer, with a bit of difference on the low end. With a tune not expecting the low-end difference, smoothness of our DD will probably be affected.

It is supposedly relatively easy to to correct for this though. I wish someone with the know-how would write up a nice DIY.

It's been posted a few times on this forum, as well as all over the internets, Just google "maf scaling howto". The only thing you need to watch out for is making sure you know which fuel system is active and needs correction.

Originally Posted by nelsmar

Does perrin provide the MAF scaling for the 2.5"?

I don't thinks so, they have a csv for the corrected maf table for the 3" though. Honestly that is the only one I would consider using anyway, the 3" intake that is.

[s2d4]

Originally Posted by Malt

Only the 3". The 2.5", just like almost all other intakes, are sold with the thought that it should be safe to run in stock form. Unfortunately, as I'm sure you are aware, they almost all make power just by leaning out the engine.

Ideally, there would be some how to post about how to scale your MAF correctly since buying a tuning solution gives you the ability to make these changes. I'm sure that is something that would be incredibly useful to tons of people on these forums (including myself).

Here is such a post by jamesm.
http://www.ft86club.com/forums/showthread.php?t=53773

EDIT: Looks like he made it private after he was banned.

[mad_sb]

Originally Posted by Snoopy_TXR

^this is exactly why I haven't purchased the OFT. I'm running the 2.5" Perrin CAI too and am not going back to the ugly stock intake box after spending hundreds of dollars on an aftermarket intake.

I have read that running the Perrin CAI can cause the engine to run rich, which is bad for the engine on the long run. I have also read that noobs should not attempt to tune/correct the discrepancies theirselves because it can lead to bigger problems, ultimately destroying the engine on the long run. It worries me to purchase a product that can lead to big problems on my new car

For us noobs, to spend another $200 for an e-tune on top of purchasing OFT just to run safely with the Perrin CAI isn't fair. Can SHIV or someone please help us guys use the OFT safely with 2.5" Perrin CAI?

I have done a lot research on the OFT and would really like to purchase one but this issue is what is holding me back on pulling the trigger on ordering one.

If power is your goal, you would be FAR better off to put your stock airbox back on and run the tune.

[nelsmar]

Originally Posted by s2d4

Here is such a post by jamesm.
http://www.ft86club.com/forums/showthread.php?t=53773

EDIT: Looks like he made it private after he was banned.

And that was just for closed loop operation which won't help with the WOT bits. You guys could always buy the 3" and then plug in the mAF scaling into the rom, I don't know if its safe on the OTS rom as I don't use it a ton. If someone is in AZ and has a perrin 2.5" with a nice clean filter and wants to loan it to me for a bit I can scale it on a stock car and post just the maf scale. But again that wont tell you if its safe.

[DAEMANO]

No disrespect intended, but I don't understand why you would buy a part not knowing how you were going to make it compatible with your car.

Also I don't understand why people buy intakes for this car when the stock intake has proven to make roughly max attainable NA power.

You should liquidate this part because even if you find a way to get it functional, it probably won't give you much if any gains at all. The fact that you seem to want to keep it because the stock box is "ugly" (which I don't think it is), isn't really the problem of any tuner who's services may be out of your budget because your upgrade dollars were spent on that intake . $200 for an E-tune is a very good value.

Originally Posted by Snoopy_TXR

^this is exactly why I haven't purchased the OFT. I'm running the 2.5" Perrin CAI too and am not going back to the ugly stock intake box after spending hundreds of dollars on an aftermarket intake.

I have read that running the Perrin CAI can cause the engine to run rich, which is bad for the engine on the long run. I have also read that noobs should not attempt to tune/correct the discrepancies theirselves because it can lead to bigger problems, ultimately destroying the engine on the long run. It worries me to purchase a product that can lead to big problems on my new car

For us noobs, to spend another $200 for an e-tune on top of purchasing OFT just to run safely with the Perrin CAI isn't fair. Can SHIV or someone please help us guys use the OFT safely with 2.5" Perrin CAI?

I have done a lot research on the OFT and would really like to purchase one but this issue is what is holding me back on pulling the trigger on ordering one.

[s2d4]

Originally Posted by nelsmar

And that was just for closed loop operation which won't help with the WOT bits. You guys could always buy the 3" and then plug in the mAF scaling into the rom, I don't know if its safe on the OTS rom as I don't use it a ton. If someone is in AZ and has a perrin 2.5" with a nice clean filter and wants to loan it to me for a bit I can scale it on a stock car and post just the maf scale. But again that wont tell you if its safe.

How would you do OL MAF scaling?
Would I still need it is my LTFT is always between -2 and 0?

[nelsmar]

Originally Posted by DAEMANO

No disrespect intended, but I don't understand why you would buy a part not knowing how you were going to make it compatible with your car.

Also I don't understand why people buy intakes for this car when the stock intake has proven to make roughly max attainable NA power.

You should liquidate this part because even if you find a way to get it functional, it probably won't give you much if any gains at all. The fact that you seem to want to keep it because the stock box is "ugly" (which I don't think it is), isn't really the problem of any tuner who's services may be out of your budget because your upgrade dollars were spent on that intake . $200 for an E-tune is a very good value.

Some people want to pay for audible gains. This seems to be the most common reason I see people buying intakes. Removing the OEM snorkel screws with the MAF and you need to modify the scaling a bit, as well as it changes its efficiency.

[Malt]

Originally Posted by s2d4

How would you do OL MAF scaling?
Would I still need it is my LTFT is always between -2 and 0?

Found this http://www.romraider.com/forum/viewt...hp?f=33&t=5321

As far as I've read, a range of 2 or less is almost perfect.

[nelsmar]

Originally Posted by s2d4

How would you do OL MAF scaling?
Would I still need it is my LTFT is always between -2 and 0?

Disable the LTFT set a nice flat target AFR, make sure timing is conservative and not going to cause an issue. Set OL to activate at lower points (such as low throttle) and do a number of pulls back to back for consistency. Adjust the MAF until the AFR flattens out. Keep in mind due to ethanol content in fuel you may be slightly rich / lean. These cars typically run a tad on the lean side on cars I test in AZ due to average 7-10% ethanol from fuel I have tested. It is minor but consistent. Altering the MAF to completely match the AFR can shift the load calculation falsely by a very small margin. But at this level its so minor it isn't a huge deal. Always verify with multiple pulls that it is consistent. And verify you are in open loop and no longer in the tip in position. Try throttling in at different RPM and you will see what I mean on the tip in position, you will see a bit of richness typically before it levels out.

Also try to keep it logarithmic. Visually inspect your MAF with a chart and verify you don't start adding a horrible jagged edge. Also consider that if you are lean in between two voltage points and rich at the voltage points you may need to shift both points up, then shift the g/s on the next readings over as it may be skewing your results. Its best to start off by simply shifting the entire table up and down by a small % to get the table as centered as possible before touching any of the MAF its self. People tend to dig them selves holes and start altering the maf a lot more than they need to.

Also only log what you need to avoid a higher latency and lower resolution datalog. Get coolant temp and IAT in there to verify you aren't getting a shift of AFR due to temperature related conditions.

[Snoopy_TXR]

Originally Posted by Malt

I'm sure there are tons of people who would love a map designed and tuned around the perrin 2.5" intake, but what about all the other people who were mislead into buying various other intakes that need tuning to run properly? Should Shiv spend his time making custom maps for every single intake out there, especially after its been shown that intakes make barely any power, if at all, after a tune over just a drop in filter and modded snorkel?

What is not fair is the unreasonable expectations people have for someone who is selling a product and offering FREE off the shelf maps based on a certain set of modifications and then complain that he doesn't offer FREE maps for your mods. That is exactly what the etuning service is for. I'm sure you don't work for free and its unfair to expect Shiv to do so.

That's true and I acknowledge that. I'm stubborn and hate the look of the stock intake so I guess I'm SOL.

I guess I won't be purchasing an OFT until someone here who has the knowledge to tune/adjust the run too rich with the 2.5" Perrin CAI.

I can only hope someone with knowledge will figure this out and share a stepxstep, DIY. for us cheap noobs lol!

[Snoopy_TXR]

Originally Posted by nelsmar

Does perrin provide the MAF scaling for the 2.5"?

I have not seen any. I only found scaling for the 3".

[Kodename47]

An easy calculation for open loop:
((Combined trims + 100)/100) x AFR = AFRx
AFRx/Commanded AFR = MAF Error (x 100 for a %)

Do a few runs and generate a spreadsheet with the data. I then find my MAFv data points and move them by the average error, removing any obvious large changes caused my sensor error, tip in etc.

Eg, MAF error at 3.81v is 95.6% (richer). The MAF g/s at this point is 100. The resultant MAF value will be 95.6 g/s.

STFT are 0 in open loop. Once this is dialled in your LTFT should also end up being almost non existent.

[s2d4]

Originally Posted by Kodename47

An easy calculation for open loop:
((Combined trims + 100)/100) x AFR = AFRx
AFRx/Commanded AFR = MAF Error (x 100 for a %)

What is AFRx?

[mad_sb]

Originally Posted by s2d4

What is AFRx?

actual measured afr