ok, how long can I go w/o tune

so I'm thinking about swapping in my vf52 along w/ 650 injectors and a walbro on labor day weekend. How long would it be safe to drive w/o getting it tuned? I'm stage 2 right now. my plan right now would be to get it tuned on that Friday, but I'd need to go to work on Tues, Wed, and Thurs. Thoughts?

Same deal for me too. I have my AVO pump in but still need to install the VF52 and 650 side feeds. My Cobb AP has a Stage II TDC map now.

talking to some tuners.. staying out of boost should be ok with upgraded injectors to drive to the shop that day.. I'm not sure about extended use over a few days.. I'd call your tuner and see what they say about driving the car all week.. I'm sure someone will have some input here also..

I wouldn't drive it on a stage 2 tune with new injectors and a new turbo without tuning for it. You might be okay staying out of boost, but it seems like too much risk to me.

Just get an infamous tune... Have him make you a map before you do your install, do the install, flash the map, and then do some runs Simple as that, you wont have to worry about messing anything up.

well, I thought about that, but patience is not my virtue. I'd have to get a wideband O2 and have it installed somewhere, and then go through the process of tuning. the other way, i just drop it off and have it done. Although, I'd like to have the more involved process, there's too many variables for the other option. I don't have a laptop either, so I'd have to borrow a friends a few times to get it done.

I don't think you will be okay driving on the injectors without a tune. The turbo and pump will be okay...but I think the injectors will give you drivability issues.

ok, maybe i'll wait until the night before to do the injectors then. Actually, I'll call the tuner and see what he says.

You would be lucky if the car even started with 650cc injectors. See if the tuner can email you a base map for the injectors to get you to the shop.

I've switched vendors and I'm actually getting a VF52 and DW740 injectors shipped out to my this week! Yay after 5-6+ months of waiting! Any ways I've started modifiying a base stg2 map myself with AccessTuner. Any suggestions on what I need to look out for? Some changes so far...

 

Injector Latency: 7.74,2.88,1.69,1.20,0.84

Scale: 3654

 

WGD:

High: 90.48 90.99 72.93 67.41 58.88 57.37 60.38 61.39 61.39 61.89 61.89

Low -10 everything

 

Boost:

0.97 12.08 16.24 16.53 16.53 16.53 16.53 16.51 16.43 16.24 15.27

If you install larger injectors you need to tune for them immediately, without a tune the car would be so rich I'd be surprised if it would run.

 

BLKGT5, over on romraider Mickeyd posted a map for a VF52 on a LGT with stock fueling. As long as you follow his pill size you could start there for WGDC. Personally I would start with all WGDC set to 0 and slowly scale them up to hit boost targets. If you haven't already, read the tuning guide over on Nasioc, I think by badnoodle. That really helped me, as I'm still a newb self tuner.

I assumed I would be in a safe range starting out if I modified the

Injector Latency: 7.74,2.88,1.69,1.20,0.84

Scale: 3654

 

Which I calculated from the help files and other owners that run DW740's

 

Good idea, I'll should start with a low WGD settings.

As stated the injectors are simply going to be a no go.

So you are saying even if I change these values and reflash the ecu that the car wouldn't run correctly with the larger injectors?

So you are saying even if I change these values and reflash the ecu that the car wouldn't run correctly with the larger injectors?

No in your case you should be ok.

I figured I wuodln't be able to drive much on the new injectors...just didn't know if it was at all. I believe I doin't need a retune for the fuel pump, so maybe i'll tackle that before.

I had the same issue with my car. I installed 740's hta68, fp. I drove to the shop just fine the next day. I kept it out of boost, and never climbed over 3k rpms. My tune shop said its fine. It worked great for me, but what do I know, there are alot more experienced people on this forum!

I had the same issue with my car. I installed 740's hta68, fp. I drove to the shop just fine the next day. I kept it out of boost, and never climbed over 3k rpms. My tune shop said its fine. It worked great for me, but what do I know, there are alot more experienced people on this forum!

I had a customer do this as well, but I surely wouldn't try to go to work 3 different days like that.

You would be lucky if the car even started with 650cc injectors. See if the tuner can email you a base map for the injectors to get you to the shop.

 

If you install larger injectors you need to tune for them immediately, without a tune the car would be so rich I'd be surprised if it would run.

 

As stated the injectors are simply going to be a no go.

 

My car started and idled fine with Perrin 816s. The shop that installed them drove the car around the building before giving me a chance to tune them. I was surprised too.

 

Then the shop's tuner was adamant that I should scale them at 680 or something. I believed him at first, and drove home that way. I wouldn't recommend any of those of course, but cars are way less sensitive to injector changes than forum posts would lead you to believe.

AF learning will accomodate a change of roughly 15%. So, figure 550 x 1.15 = 632 and you'll still run pretty close to stoich.

 

740/632 = .85

14.7 * .75 = 12.5, so that's the AFR you'd be running at until the injectors get tuned.

 

Not so bad, really. There is reason to believe that our motors can run pretty well - pretty strong, even - with AFRs down into the 10s.

I had a customer do this as well, but I surely wouldn't try to go to work 3 different days like that.

 

no def not, It was just a 15min jaunt there. I was told you could get bore wash (correct me if im wrong)

The stock tune runs AFRs down into the 10s without bore wash. If you stay out of boost you'll be up in the 12s.