# VRT leans out under throttle after headspacer install.



## DannyLo (Aug 2, 2006)

MKIV
24v
Old C2 (Jeff A) Tune
630cc Injectors

Just put a headspacer in the car so I can raise the boost, however, I'm still running the old boost off the spring which was 7psi because I haven't had a chance to put in my fuel pump yet. I drove it a bit and finally laid into it a little with the 7psi and saw a 13.x on my AFR gauge and so I jumped off the throttle and cruised home. It's fine at idle hovering around 14.7, no codes in the computer either. I used to get mid 11 AFRs before the spacer @ 7psi.

Is this all because my current tune is a 'stock compression' version 630cc file? I was planning on meeting with Jeff soon anyway to get a few tweaks and a 2step done to the ECU but I wanted to see what you guys thought of the situation.

Cheers
-Dan


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## sp_golf (Nov 28, 2007)

That's strange, it's possible that the ECU needs to re-learn and honestly, low 13 AFRs aren't that dangerous at 7psi with a head spacer and high octane, the timing is probably conservative too since it was a stock CR file.
You could try resetting the ECU, throw in some octane booster and go for a few pulls, if the AFRs are in the low 13s in the beginning do a few pulls and see if it starts to richen out.


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## masterqaz (Oct 5, 2007)

hes right theyre not that dangerous. i was running .5bar on 8.5-1 and i never saw it pull timing and it was leaning out between 13-14. 13.1 was the fairly constant number.

Dont think the 630 tune would have been made for stock comp. 

reset fuel trims and boost around some.


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## Capt.Dreadz (Jun 4, 2003)

masterqaz said:


> Dont think the 630 tune would have been made for stock comp.


I got an old 630 spec sheet written by Jeff and it doesn't mention anything about modding the CR.


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## DannyLo (Aug 2, 2006)

*FV-QR*

Yeah, I'm going to drive it a bit and see what goes on. I'm going to log as well and see if there's any knock activity which I'm doubtful of because it moves like before the spacer was in so I don't think it pulls timing.

Tomorrow we'll see if it starts to settle back in to a groove. I've only put 20-30 miles on it since the car was put back together with the first 25 or so being real easy to make sure the car was good/no leaks etc, so I think it's still learning.


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## Capt.Dreadz (Jun 4, 2003)

Wutcha go with? 9:1?


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## TBT-Syncro (Apr 28, 2001)

Capt.Dreadz said:


> I got an old 630 spec sheet written by Jeff and it doesn't mention anything about modding the CR.


Jeff's tunes never took compression in to account. His assumption is that if you had lower compression, you had higher boost.


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## Dave926 (Mar 30, 2005)

And with a change in compression a slight change in timing give it a little time to adapt


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## DannyLo (Aug 2, 2006)

Yeah it drops down to high elevens now. The car has 150 miles on it now since I finished it. Needed that 100 miles of highway bombing to get it back to normal I guess.

Yep It's 9:1



TBT-Syncro said:


> Jeff's tunes never took compression in to account. His assumption is that if you had lower compression, you had higher boost.


Really, I was under the assumption that I had to get the file tweaked/changed when I lowered the compression, and couldn't just add fuel pump, more boost, and go. This was the C2 guys that told me this when I first got my setup. 

Was this just a moneygrab? Maybe this was part of the reason he left  because C2 told me I need another 5-600$ "stage 2" flash :sly:


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## SVTDanny (Aug 8, 2005)

Their whole "stage" system is a scam - in fact, everything about them is a scam. 

Their OBD1 12v tune has terrible driveability problems, and they have made zero effort to help out in any way. I have tried contacting them via several mediums, several times and I have been lucky to get anything more than an automated response, much less any actual assitance. 

Selling products that are half assed, and then not supporting them in any way. Awesome business model. :thumbdown::facepalm:


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## Dave926 (Mar 30, 2005)

djsheijkdfj said:


> Their whole "stage" system is a scam - in fact, everything about them is a scam.
> 
> Their OBD1 12v tune has terrible driveability problems, and they have made zero effort to help out in any way. I have tried contacting them via several mediums, several times and I have been lucky to get anything more than an automated response, much less any actual assitance.
> 
> Selling products that are half assed, and then not supporting them in any way. Awesome business model. :thumbdown::facepalm:


Waiting for a certain nut swinging troll to post a response to this


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## TBT-Syncro (Apr 28, 2001)

Lieutenant Dan said:


> Really, I was under the assumption that I had to get the file tweaked/changed when I lowered the compression, and couldn't just add fuel pump, more boost, and go. This was the C2 guys that told me this when I first got my setup.
> 
> Was this just a moneygrab? Maybe this was part of the reason he left  because C2 told me I need another 5-600$ "stage 2" flash :sly:


you sure it wasnt for larger sized injectors? perhaps the mk4 tunes are different. But i know that with the obd2, that it was fueling, and not timing changes.


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## therealvrt (Jul 21, 2004)

Dave926 said:


> Waiting for a certain nut swinging troll to post a response to this


Calling slcturbo..... Opps i mean van halen
:facepalm:


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## DannyLo (Aug 2, 2006)

TBT-Syncro said:


> you sure it wasnt for larger sized injectors? perhaps the mk4 tunes are different. But i know that with the obd2, that it was fueling, and not timing changes.


Nope Injectors stayed the same with the 630cc injectors I have now, and 4" housing. None of that hardware changes throughout C2's old "stage" system for the 24Vs. 630cc from Stage 1 to Stage 3.


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## V-dubbulyuh (Nov 13, 2005)

Lieutenant Dan said:


> Yeah it drops down to high elevens now. The car has 150 miles on it now since I finished it. Needed that 100 miles of highway bombing to get it back to normal I guess.
> 
> Yep It's 9:1
> 
> ...



That 630 fille was written with the assumption that your car was going to be running lowered compression. I have not run that particular file at stock compression (only 9:1 and 8.5:1) so I can't attest to if there is any difference or not but I do recall Jeff always stating that the file assumed your car was running lowered compression. Maybe the C2 ad has changed (I have not looked recently) but the verbage was to the effect of "requires lower compression and fuel pump upgrades".

As an aside, it is typical that the car's AFR will run less than ideal in boost (sometimes even at idle) until it has adapted/trimmed. Glad you got that sorted out.

_Edit to add C2 description:_
_*Stg 2
Combine this Flashload with 60# injectors and our 95mm MAF housing for a plug'n play tuning solution for MK4 24V equipped cars. Supports up to 400hp.

C2 SS Low CR spacer suggested
C2 MK4 Fuel Pump kit suggested


Stg 3
Combine this Flashload with 60# injectors and our 95mm MAF housing for a plug'n play tuning solution for MK4 24V equipped cars. Capable of producing 600hp.

This is a High Performance software tune that requires a fully engineered engine system that is capable of handling the power. Fully BUILT bottom end is required, as well as supplementary fueling system components.*_

Thus it can be assumed Stg 3 is also intended for lower compression though not directly stated, "fully engineered engine system ". Being more aggressive than their Stg 2 it follows that low compression is required. This could be more clearly stated/advertised though.


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## DannyLo (Aug 2, 2006)

*FV-QR*

Yeah, see they got rid of their Stage 1, which was the same setup injectors and MAF, but without the headspacer for those who wanted to start bare bones and run low boost on stock CR for a while, like I did.

If I can just add the fuel pump (wiring up next weekend) and up the boost on the same file it'd be wonderful. 

I'm still going to visit Jeff at some point whether I need a file tweak or not because I want him to add that 2step  Completely pointless because I only go to the track a few times out of the year, but I want to make noise 



V-dubbulyuh said:


> That 630 fille was written with the assumption that your car was going to be running lowered compression.


Maybe, but it was offered originally to be run on stock compression cars as well. However I'm not sure if they were different from each other slightly, or if it was the same 630cc file for stock and lowered CR. There were a few of them out there with their old stock CR setup, and I was one of them. Like I said, it would be nice if I can use the same file and just up the boost.


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## V-dubbulyuh (Nov 13, 2005)

Lieutenant Dan said:


> Maybe, but it was offered originally to be run on stock compression cars as well. However I'm not sure if they were different from each other slightly, or if it was the same 630cc file for stock and lowered CR. There were a few of them out there with their old stock CR setup, and I was one of them. Like I said, it would be nice if I can use the same file and just up the boost.


I hear you and it is plausible since it appears the 24v platform is using the* same 630 inj *for multiple "stages". If you currently have "Stage 1" then it makes sense that your fuel maps and timing will not support higher boost numbers of the "Stage 3". I suspect that you will need to return the ECU/upgrade. When you initially said 630 setup I associated that with a Stage 3. 

I was one of a handful of original people on the 12v 630 "Stage 3" (before it was publicly released) and there was never a stock CR version of that file (that I'm aware of). The less aggressive 12v programs however ran smaller injectors (36/380 & 42/440) and therefore completely different files (ie for a 12v 630 was unique to Stage 3). 

Speak to C2 directly and give them the software version so they can tell you exactly what you have. :thumbup:


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## Capt.Dreadz (Jun 4, 2003)

I think "Suggested" means needed if you plan on running more boost. Again, i don't think the 630 files cr set unless stated & even then, i think C2/UM tweak other things for those "special request".


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## DannyLo (Aug 2, 2006)

*FV-QR*

I'm not sure if I read that correctly, but you're saying just add fuel pump, raise boost in increments and see if my AFRs stay good? 

And to dubbulyuh, I'm done speaking to C2. I can't get in touch with them no matter how hard I try, and frankly I want Jeff to continue to tune my car, not C2. I know my Tune was "C2", but Jeff wrote it for them, and he's local so I'll check with him.


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## Capt.Dreadz (Jun 4, 2003)

Lieutenant Dan said:


> I'm not sure if I read that correctly, but you're saying just add fuel pump, raise boost in increments and see if my AFRs stay good?
> 
> And to dubbulyuh, I'm done speaking to C2. I can't get in touch with them no matter how hard I try, and frankly I want Jeff to continue to tune my car, not C2. I know my Tune was "C2", but Jeff wrote it for them, and *he's local so I'll check with him*.


 ORLY :sly: Maybe you can get him to overlook my old C2 630 tune 

It won't hurt to install an inline pump. Stock tank pump & lines won't cut it if you plan on turning up the boost. 
I wonder if you could check the fuel pressure right before it hits the rail while under boost. You could see if the inj. are getting enough fuel or not. I think this can be done via VAG-Com. Just datalog it while on a good run.


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## V-dubbulyuh (Nov 13, 2005)

Stock lines will be fine... the limitation will be the pump. That with the correct tune will get the OP to the mid 20's safely.


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## DannyLo (Aug 2, 2006)

Yep he's local, right in Southern CT. I'm here right now so he's a few minutes away but even from LI he's only a ~2 hour ride, or less if you take the ferry over.

Already have a pump sitting at home as well, just haven't installed it yet. I'm going to try to get on that this weekend and then really hoping to see Jeff before H2O so the car can be *complete

I say *complete because i'll be done with this phase of the turbo build, but this car never ends :laugh:


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## CorradoFuhrer (Mar 21, 2002)

DannyLo said:


> MKIV
> 24v
> Old C2 (Jeff A) Tune
> 630cc Injectors
> ...


Definitely searching here, but is it normal to have to run these tunes for a while before they dial down?


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## 24vGTiVR6 (Sep 14, 2010)

I had to drive around a bit before I could see the AFR's @ WOT stabilize to ~11.5. Fresh after the build WOT was 13ish.... but then it corrected itself over time.

so yes, this may be the case.


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## CorradoFuhrer (Mar 21, 2002)

24vGTiVR6 said:


> I had to drive around a bit before I could see the AFR's @ WOT stabilize to ~11.5. Fresh after the build WOT was 13ish.... but then it corrected itself over time.
> 
> so yes, this may be the case.


thanks for the reply, how much time did it take? You have a mk4 though correct?


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## 24vGTiVR6 (Sep 14, 2010)

Corrado****** said:


> thanks for the reply, how much time did it take? You have a mk4 though correct?


I'm no tuning expert, but that seemed to be the case with me. At least it seemed so, as no changes were made - yet the AFR's went into acceptable range @ WOT after about a week of driving to work and back.... maybe ~1000 km's or so. I saw it lean out @ WOT initially after the build, so I just chose to take it easy for the remainder of the break-in. After break-in had concluded I switched over to synthetic (from break in oil) and tried out WOT again.... lo and behold AFR's were in the acceptable range.

Yes, I have an MKIV.... so it may be different if you're OBDI. Like I said, I don't know any of this for sure. But, these are my observations.


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