Should LTFT be this high with Cobb SRI?

[PaPaSpeed]

I was trying to watch my LTFT a little bit today, and I was mostly in the 4.7 - 8.6 range while cruising and accelerating. I have the CP-E Nano, and I'm sure its similar to the Cobb SRI. I'll keep an eye on it over the next few days, and report back. My AFR is around 14.2, I'd like to see that a little lower.
That's the trouble with a dashhawk, you know too much, maybe not knowing is more comforting. But I'm having fun with it, and that's what counts.

 

[DaleNixon]

14.2 is fine. You just want it to get a little richer (lower) during hard acceleration. I've never seen any problems with AFR with the stock airbox vs. HKS intake vs. Cobb intake.

And yea, the Dashhawk kicks ******* ass, but it sucks how paranoid it makes me! I used to think "no CEL, no problem!" Now I've got a damn knock warning and I constantly watch certain parameters.

It reminds me of when I was a kid and I was afraid to put my hand on my heart for the pledge because I was afraid it might stop! Haha!

 

[Lee456]

I know what you mean, Dale. The Dashhawk is great but when I had the Cobb on there I was completely satisified until I hooked up the Dashhawk and saw the LTFT hit 14.8 under acceleration. The Dashhawk was real helpful when I switched back to the factory airbox the other day, though. I forgot to hook up the MAF sensor plug when I changed late at night. I had an early morning appointment and when I started the car it sputtered and died after about 1 second. I remember the connector, hooked it up, and started the car but of course had a CEL. It was great to just hit a couple buttons on the Dashhawk and reset it.

My CP-E Nano should be here Wednesday afternoon. I'll give it a couple days then post the LTFT's. I expect them to be about like the Cobb SRI although PaPaSpeed is getting much better numbers than I got with my Cobb. We'll see. If the numbers are like my Cobb and I like the intake and it doesn't shriek like a jet engine as a couple people have said, I'm going to just live with the LTFT's as long as the A/F ratio is OK.

 

[PaPaSpeed]

Too bad you guys don't live closer. I'd swap you my Nano for a few days to try out before you buy one. I don't see a big difference between the Cobb and the Nano. I guess you you'll find out.
By the way, the outside temp here today was about 45. Looks like you may be warmer. Does that make any difference?

 

[Lee456]

Thanks for the extremely generous though. It's nice to know that someone would go to the trouble to swap parts to let me try the new one before buying it. Actually, after reading about the LTFT's, some stuff about how the ECU works, and some comments from people here and on another forum in answer to my questions, I had decided it was reasonable for the LTFT to be high to compensate for the extra air let in by the SRI. I don't expect the Nano to be significantly different. If it stays under 10 I'll be real pleased, since I understand the limit of the ECU to compensate is 25%. 14.8 was getting closer to 25 than I'd like. 8 or 9 would be better.

The main reason I'm switching is the battery box problem. Not much has been said about it here, but the other forum has a LOT of comments and even some pictures from people who have had the sheet metal piece break off. I was going to make a different attachment for the Cobb, but it would have required cutting and drilling the bracket. The rubber piece in the Nano mount should help some. If that doesn't prove sufficient it would be easy to build smething else for it to attach to that would run down to the thicker bolts a few inches further away. I'm curious what it will sound like though. The Cobb sounded good, but some people have said the Nano shrieks like a jet engine. Others have said it is not loud. I'm real curious about that. How have you found it to be?

As for the temperatures, it's no doubt warmer here than what you've got, although we've had some unpleasant weather for Phoenix. A few days while I was running the Cobb looked more like what I'd expect in Seattle. Low 50's and rain. Of course, at that time Seattle looked more like Alaska with a foot of snow. Must be global warming.

 

[PaPaSpeed]

The main reason I'm switching is the battery box problem. Not much has been said about it here, but the other forum has a LOT of comments and even some pictures from people who have had the sheet metal piece break off. I was going to make a different attachment for the Cobb, but it would have required cutting and drilling the bracket. The rubber piece in the Nano mount should help some. If that doesn't prove sufficient it would be easy to build smething else for it to attach to that would run down to the thicker bolts a few inches further away. I'm curious what it will sound like though. The Cobb sounded good, but some people have said the Nano shrieks like a jet engine. Others have said it is not loud. I'm real curious about that. How have you found it to be?

Well, the Nano does sound like a jet engine winding up, but its not too loud. You'll definitely hear it sucking air, but its not too bad. I kinda like it.
As far as the battery box bracket, the Nano seems to cushion the vibration with that rubber bushing on the bracket. I haven't had any problems with it. The Nano is a relatively new product, so we'll have to reserve judgement til its been tested for awhile.

Back to LTFT, have you considered the Standback from CPE? I understand you can adjust LTFT, AFR, and others if you want to tune yourself. I don't think I'm knowledgeable enough to do that, but others seem to have some fun with it.

 

[Lee456]

I got the Nano today and put it on. I didn't have a chance to drive it much since it was late afternoon but with about 20 miles on it the LTFT is +3.9 at idle and +4.7 when accelerating. At steady speeds it hits +7.0.

For now they are way lower than they were with my Cobb SRI at the same point. At 20 miles it was +8.6 at idle, +13.3 when accelerating, and +4.7 at constant speed. Interesting that the Cobb was lowest at steady speed and the Nano is highest at steady speed.

I'll post these again when I've got 100 miles or so on it, but if they stay under 10 I'll be happy. It certainly does sound different than the Cobb but it's not a bad sound. I actually like it.

 

[DaleNixon]

I'm going to shoot Cobb an email or call them today. If these LTFT's are going to be detrimental to my car, I might go back to my HKS intake. That would be some ironic s*** right there.

 

[DaleNixon]

Chris at Cobb wants me to send him some Dashhawk data logs (AFR/STFT/LTFT/RPM/Abs Throttle). He's saying these numbers (14.1 at moderate acceleration) are higher than they should be.

I'm going to log my drive home from work today and email it to him. I'll keep this thread updated.

 

[CWPspeed3]

Chris at Cobb wants me to send him some Dashhawk data logs (AFR/STFT/LTFT/RPM/Abs Throttle). He's saying these numbers (14.1 at moderate acceleration) are higher than they should be.

I'm going to log my drive home from work today and email it to him. I'll keep this thread updated.

The people at cobb say it shouldnt be that high yet it seems that everyone on the forum is reporting that high? thats a good sign...

 

[Lee456]

I didn't record logs in the Dashhawk, but I watched mine carefully, recorded the LTFT's on a voice recorder and typed them into a document on the computer when I got home each time. I'd be willing to swear to this:

After 90 miles with the Cobb SRI (switched to Amsoil filter for the last 40 miles which made no immediate change):
10.2 idle
8.6 constant 50 in 5th changing to 10.9 on slight hill
14.8 acceleration moderate to WOT

Those were my final numbers before removing the SRI and going back to the modified factory airbox. They had not changed since 50 miles other than the acceleration number went from 13.3 to 14.8 between 80 and 90 miles after the install and ECU reset. As I've said before, the car was running great with no sign of any problem. If I didn't have the Dashhawk, I would not have seen anything wrong. I don't know if these number represent a problem of any kind, but I do know they were a fact.

With no other changes than the modified factory airbox:
-3.9 Idle
-1.6 Constant speed
0.0 moderate acceleration
-0.8 heavy acceleration

Yesterday I put on a CP-E Nano with the dry filter.
The numbers after 30 miles (the same as they were after 20 miles):
+3.9 Idle
+7.0 Constant speed
+4.7 Acceleration moderate to WOT

The only other mods on my car are a Turbosmart BOV and a Magnaflow CBE.

I apologize to all of you for posting all this again, but I thought perhaps if the Cobb people look at this thread it might be helpful to have all the information I recorded in one post.

 

[DaleNixon]

I linked Chris at Cobb to this thread in an email. I hope he comes and checks it out. I would like to find out how many miles it takes to stabilize fuel trims. Perhaps I need to just ride this out another few hundred?

Thanks for sharing those numbers again, Lee.

 

[john blutarski]

Mine now stays pegged at 14.8 under any kind of throttle

 

[DaleNixon]

Lee, is yours an '08 or '08.5? I'm just looking for a pattern here. I sent Cobb an email with my datalogs on the drive home from work. I just went out and started the car and listened for leaks around the intake.

When I started the car, it was idling with an LTFT of 10.2. After a few minutes, it was up to 12.8

I couldn't detect any leaks with my ears.

 

[jengajoe]

Dale, have you recently checked the tightness of the turbo inlet clamp? I have to push the inlet tube all the way on and re-tighten mine every couple months... time for some t-clamps. The damn stock clamps have a habit of loosening up over time.

 

[DaleNixon]

Are you talking about the clamp between the intake and the inlet? Or the inlet and the turbo?

If it's the latter, how do I access that clamp? Thanks!

 

[Lee456]

Mine's a 2008, although I bought it in late July. I sure do hope Jengajoe is speaking of the clamp where the intake attaches and not something under the car needs tightening every couple months. For what it's worth I've double checked every clamp involved in each intake install, then rechecked them after an hour or so of use and again after a few days. All were tight.

I have not checked anything else for tightness, but I believe that if the source of the high readings was a loose clamp not involved in the intake install the numbers would stay high as I switched to the modified factory airbox and now the CP-E Nano. Instead, I got minus LTFT's with the factory airbox and numbers similar to those reported by PaPaSpeed who has a Nano when I installed the Nano.

 

[jengajoe]

I sure do hope Jengajoe is speaking of the clamp where the intake attaches and not something under the car needs tightening every couple months.

Yup, be sure to check the clamp that clamps the inlet tube to the inlet side of the turbo. It's a b**** to reach but I get at it from the top.

 

[DaleNixon]

My connections are fine. My LTFT's are not.

***THIS IS ALL RUMOR AND NOT CONFIRMED:
I'm starting to hear chatter that some of the Cobb SRI's from the newest batch might have improperly shaped/sized MAF housings or intake tubes. I'd love to get Cobb's take on this, but they are not answering my phone calls or emails (busy in Plano I suppose).
***END RUMOR

Does anyone know anything about this potential problem?

 

[john blutarski]

My connections are fine. My LTFT's are not.

***THIS IS ALL RUMOR AND NOT CONFIRMED:
I'm starting to hear chatter that some of the Cobb SRI's from the newest batch might have improperly shaped/sized MAF housings or intake tubes. I'd love to get Cobb's take on this, but they are not answering my phone calls or emails (busy in Plano I suppose).
***END RUMOR

Does anyone know anything about this potential problem?

My LTFT's are very close to yours and my SRI was from before they went on "worldwide backorder" last year.