Okay guys, I just had Hitman tune my car over the weekend. The car is
running better right now but it has a little problem. For those who
don't know who Mat "hitman" is, he's known as the number one tuner
for rotories in the world.

I just installed the K2RD 1600cc assy. 10 ohm, 10watt resistors.
SX fuel regulator at ~40 psi at idle.

It will not transistion smoothly. ~ 3800 to 4000 rpm, when it goes
from vacuum to boost, it hesitates real bad. Mat says it's the
injectors not opening fast enough. He tried to tune it out, but
couldn't do it. When you gas it smoothly, it's bearly noticeable.
When you full throtle it, it jerks really bad!

I've read every Tom Dick and Harry's version of what resistors to
use. No one has any concrete evidence of what's correct.I called
K2RD, they told me 10 ohm, 10 watt. But this info is coming from
people that advertise that their injectors are high impedence. They
also claimed that it's a bolt on and, they don't even use pfc. Is pfc
not able to handle the 1600's. Over the weekend Mat tuned over 8
cars. Haltech, Motech, and PFC. Other RX7's with 1600 injectors
didn't have the problem. Haltec handled anything that was thrown at
it. I and one other guy had the PFC. Same problem. Anyone know how to
fix the hesitation. Someone on the list said a slight hesition is
part of the 1600 injection deal. I can't take that deal.


My theory is, if Mat can't tune it, no one can. I saw this guy tune
cars all weekend. He makes cars come alive and he takes his time. No
bullshit. But who knows. If anyone can help, please, please jump in.
I've spent too much money and too much time for this bull.

 

May need an injector overlap adjustment (as well as lag time), only possible with the Datalogit or Apexi software. Typically requires and increase in the stock settings. Someone with a Datalogit and a bit of experience should be able to fix it right up.

I had to adjust my overlap with the 1300 secondaries (bored 850's). After a few adjustments, transition is invisible.

 

I have the DataLogit. How did you set the settings to eliminate the lag? (Method please)

 

did matt use your datalogit to tune by?

are the 1600 cc injectors (and their lag time) input in the injector screen in the datalogit?

Tim

 

Go to Settings 5, there a box labelled "Injector Overlap", up your overlap until the car responds to your liking.

I used 7, 7, 3 from top cell down. Your optimal settings will most likely be different by a few. Stock is 3, 2, 1.

I still haven't figured out the injector lag adjustments, just calc what the book instructs you to and use it.

 

For some reason he didn't have the updated software. I gave him my laptop, but he didn't really use it. He spent 2.5 hours on the dyno but only used the commander.

 

Once the tranny gets fixed, I'll head up to Arthur's and dial in the 99 spec turbos and larger primaries and see what I make at 14 to 15 psi since we are set up pretty similar.
Are you going to the track in April with David, down to Silver dollar?

See ya soon.

 

Hey Tim, Dave told me you needed a tranny. I got one sittin here on my parts car. If you want it, make an offer and it's yours. Don't worry, I'm easy. It's off of 94 touring model.

 

David told me about it, but I was waiting to make sure you didn't need it for anything. If it in good working order, no grinding etc?

Tim

 

I don't know the condition. I know it was running before it was crashed. You'll just have to look at and and take a guess.

As far as my stumbling goes, I changed the transition timing from 1.5ms to 1ms. No mo stumbling. I just can't believe the Hitman didn't know that. I feel ripped now. At least I know the car is tuned and I won't blow it.

 

Glad to hear you worked the kink out and it was a simple correction to get it running good. He should have caught it, he's human and couldn't get the commander to do that. Using the datalogit would ahve helped, hope you don't feel too riped off, but I bet if feels good now the rest of his tuning should be gold, so it wasn't competely a waste of time and money.

About the tranny, I have the bearings to try and repair mine..key word is try. I'd hold on to that one just incase your, with the extra HP your making now takes a crap like mine did. If I can't get the shop to fix mine with the bearings, I'll PM you back about it and thanks for considering selling it to me even when you might need it and then leave yourself searching for a tranny.
Tim

 

r71,

Haven't heard of folks adjusting that parameter to correct your condition, I'll try it out some time and find how it works for me. After reading up on it, I find it is supposed to set the initial secondary injector opening time at transition, reducing the primary by an equivalent amount. Given this functional description I cannot understand how it helps your condition but also cannot argue with results.

Do you recall if your transition stumble was due to a rich condition or a lean condition? I assumed a lean condition.

 

I believe the stumble is due to lean condition. The A/F gauge reads completely lean momentarily when it stumples. I changed the transition setting from 1.5ms to 1ms and it seemed to help the 4th gear pull, but the hesitation is amplified in 3rd gear now. Huge stumble. Althogh the car feels smooth, I feel ripped that he couldn't tune it out. If anyone figures it out, please help. There's got to be someone running 550/1600 without hesitation.

 

what rpm range is it occuring (around the 3K or 4K 4200 etc?) Try going in to the fuel maps and adding fuel in those surrounding cells, both left and right and above and below. It's a band aid fix and you might have already tried that, but its better than head bucking lean conditions.
We can roughly see what its doing via the stock O2 sensor, but not tune by it, but can see where its getting lean. Is it on WOT or part throttle as well, but at the same rpm range?
Tim

 

Did you ever try the injector overlap settings?

 

We've got quite a few FDs running smooth with 1600s around my parts.

How much did Mat charge for the part he tuned? What did he tune for, max HP on the dyno?

You start the thread out that Mat is the #1 tuner in the world then you're last message is that you feel ripped. Maybe Mat didn't tuned around the wrong injector overlap setting then when you put in the correct values you are suffering from the attempts to tune around it?

Sounds like you need the car tuned.