Just finished a bottom end rebuild on my B18C GSR. Engine was starting to have some blow by at 272K on boost, other than
that she was running fine, and strong. My goals was to do a build to push 20 pounds and be reliable.
9.1:1 pistons. 440 injectors. forged rods. T3 turbo.
During break in i ran the stock GSR ECU and injectors with no boost, set the rings and normal driving for a couple
hundred miles to make sure the engine was solid before switching back to tuning. Needed to know I had a solid baseline and
that the engine build was solid before making adjustments. No starting issues, no warm idle issues,
no stalling, no bucking, good power. Engine is solid for baseline. (I'm using CROME for the Tune, LSU wideband)

I first started with my 12psi tune with stock MAP, I was running this before the engine rebuild, and there were no hiccups. It was a solid tune, street
driving and for ripping around on the interstate..only had to modify a spot or two in the fuel columns but she ran great, started easy, idled smooth, pulled hard.
Moving on.....

I went ahead and switched to the GM 3 bar and modified my tune for 20 pounds.
I have been scratching my head on this one though, and must be overlooking something because at warm engine temp, if i'm backing up she wants to
stall out. I bumped the IAC up to 15%, that did help some and hasn't happened again. But starting off from a stop there's a hiccup in the where the engine will buck....it's
right at take off and again just before your second or third gear shifting point if you're just regular street driving.
I'm also stupid rich cruising on the interstate, anything cruising above the 25 inches mercury cruising i'm at 10.5. This will be an easier fix, i just need to get back out on the highway and
tune that on the fly to dial in cruising mixtures, just take some fuel away in those first two.
More than anything just needing help with the reg street driving, starting from a stop and just before shift points to second and third. Maybe it's a tip in issue...don't know.
If anyone can help, that would be much appreciated, i'll attach my tune. It's got to be something I've overlooked and just needing an extra set of eyes or something. Thanks in advance.
Also if anyone else has any ideas or added input for modifications, i'm open to all. Even though i've been tuning and running these tunes for a couple years doesn't mean i am not open
to some ideas or other person's experiences when tuning.

 

As long as your keeping the backup tunes, put your factory map sensor back on and see what happens. Are you running e85 or pump?
‘I tried a GM 3 bar but never got it to work right, I ordered a skunk2 4 bar ( probably the same as OMNI 4 bar) and all been good since.

 

Definitely have kept all known good tunes i've had, for sure good advice there. And right now, just pump. I wanted to get that tune laid out first before ethanol. I was actually looking into an E60 tune. I've heard some good things from running half a tank 93 and half E85.
And thanks for the advice about the sensor, I think you may be right.
It's very possible the new 3 bar may not be giving me the best parameters, especially having so many spotty issues when I basically laid out a copy of my 12 psi tune.
And she was running just fine with the stock honda MAP on 12
I'll look into those other sensors you mentioned as well. I will tinker with my tune for one more run, but i'm definitely not going to bang my head against wall to try and "MAKE" a possible spotty sensor work for me.... way easier to put my 12 psi tune back in temporarily and order a new MAP is the best way to go.

 

might need to check your injector duty cycle, I was running 450cc injectors with 9.1 setup before my current build, I was close to the top of those injectors at 12psi and when i swapped over to a 10.1 compression I ran out of fuel around 7-8psi .... I would advise going with some 1200-1600cc injectors if you are thinking of going with a ethanol mix fuel. You would also want to keep a test kit around to make sure your mixer is always correct, I just run e85..... much simpler. Also, what fuel pump?

 

I have noticed a lot of them are claiming to be genuine GM/Delco 3 bar map sensors but they aren't authentic. I had to look around for a bit before finding mine.

 

Thanks guys for the advice.
My current pump is a 255, but I’m looking into upgrading to the Bosch 044. I think there’s another Bosch like the 044 that’s E85 friendly, but I’ll have to do more research on it before pulling the trigger. Right now, the 255 is taking care of business. On 93 pump I’m at 12.5 full throttle at 12psi, and I had to lean it out some after initial run on my base map. I think I still have some room to grow, but I know I’ll probably need to upgrade soon.

 

I found a few different Skunk2 MAP sensors, i'm wondering which PN you went with turbo? It looks like the 1510 PN has two bolt down tabs and it even says it'll fit the B series engine but the description doesn't say that it comes with a pigtail to wire into the factory harness.
The 1500 PN is only a 3 tab but it lists some cars that are still on the road/junk yard that I could probably easily cut a pigtail off to wire into my factory harness. Thanks for any extra input on this one.

 

if you do plan to run E85, don't forget to upgrade the fuel filter as well. The factory one is paper filter and may be an issue down the line. Check out AEM fuel pumps. They have ones that are E85 compatible too.