I just installed a GMR 98 kit and had it dynoed saturday.

It made 98.4 hp and 95.1 tq, GMR has several kits like mine doing 106+ 106+ I'm in no way saying anything negative about GMR. I'm just looking for any ideas as to where I'm missing the extra power?

The guy that installed the kit is extremely capable and qualified. 15 years as a tech.

I heat cycled the motor 3 times and broke it in reasonably nice, meaning I tried to keep it under 3000 rpm's for the first 500 miles. I cheated a time or two but didn't beat the motor.

I was able to watch everything he did from a monitor. The best pull was the second one. He made 11 total and couldn't get any better results. I watched him change fuel and timing. I also watched the a/f gauge during the pull. The funny thing is the closer he got to 13 to 1 a/f the less power the bike made, so he came out and shook his head?? and told me to go with the second pull and call it good.

The tuner quized me on the kit and said thats about what the kit should do? Yada yada, you know what I mean, so I just agreed and thanked him the his time. They only charged me $30 so I was happy.

The guy that did the tuning was younger and maybe inexperienced? I making that assumption only because he was young. My plan is to go to a different tuner who is farther away when I have the time. All this guy does is tune drag cars and motorcycles so I hoping for better results for my expense of this kit.

Is it possible to be that bad of a tuner to miss almost 10hp and 10tq after 11 tries?

 

Geez, I guess it's possible. But I like your idea of going to another tuner. I'd recommend NOT sharing the results of the first tuner, just to get an independent perspective. Let him know that you think it ought to be pulling harder and stronger. Seat of the pants thing, and let him see what he can do. The real difference is in the tuner. The equipment is all the same. Let us know how it goes.

 

I will definately take your advice on that!

 

Something you might find helpful:

Gentleman here are five questions you can ask your tuner to see what his skill level is without being conspicuous. These are 5 simple questions that a good experienced tuner can and will be able to spit out the answers correctly and without a great deal of thought and the whole time your asking them the questions it will seem like a general conversation of you getting a little knowledge of the tuning procedures from him. If your tuner can't answer all, or any, of these questions it's time for you to search out another shop.

1) How long will my bike be on the Dyno to tune the SERT?
(answer) 4 to 5 hours

2) How many Dyno runs will you have to make to finish a tune?
(answer) 50 to 70 on a average

3) What are people talking about when they say you have to SYNCHRONIZE the VE tables?
(answer) By Synchronizing the VE Table to the Fuel Table your telling the ECM the new air flow through the motor from the mods you made.

4) I heard something about a Step Test, can you tell me what that is?
(answer) The Step Test is a program in the winPEP 7 software (Dyno Software) that allows us to sample the AFR longer for a better reading at 2%, 5%, 7%, 10%, and 15% Throttle Position. This is where the bike lives so we want a good AFR sample to make our edits.

5) Do you change the AFR Table to one value as you tune?
(answer) Yes, 13.2. This makes it easier to synchronize the VE Table.

If your tuner can answer these simple questions chances are (99%) you will get a good tune. I hope this will give you all a better idea who your trusting your $20,000.00 investment with.

Just trying to help!
Doc

PS. If they don't answer all of the questions correctly, PLEASE give them my phone number for training - it's in my signature.

< Message edited by Doc 1 -- 4/6/2008 11:00:00 AM >

_____________________________

HDMD Tuning Center
352.242.9616
hdmd88@yahoo.com

 

The bike was dynoed, but it wasn't tuned based on your description.

 

If the build was done right and I am assuming it was, there is a lot left on the table by the tuner. And yes, as you fatten a mixture you can loose hp. There is a fine line for hp but you will find a leaner running engine making more hp, fatter for tq but again there is a balance as too lean equals heat and engine problems, too fat is poor fuel economy and thining of oil. My lowly little 95" in my RKC made 102hp/112tq with a good tune. First go around on a dyno it was 90hp/92q. Found another tuner, so the answer to your question is yes, a tuner can easily miss the mark by 10 to 20% of an engine's capabilities.

 

You've got some great advice so far.

There have been a couple of guys with those GMR 98" kits on this board in the past. You might check through some of the dyno run threads and see if you can find them. I'm pretty sure BryanTTM had one, but not sure if he ever had it on a dyno. It would be good to have several charts of the same build to give you (and maybe even your tuner) an idea what the combo is capable of. Can you get some charts from GMR?

I didn't catch what kind of a tuner you are using either. If it's a Power Commander you could be beyond its' limits for timing adjustments. If you're using a SERT a better tune will make all the difference in the world.

I also notice your sig indicates 9.8:1 compression. Is that what GMR recommended for those cams? Seems like most of those builds I have seen in the past have been closer to 10.5:1, but I could be mistaken on that.

EDIT: I also don't see anything in your sig that indicates head work was done. What's the story on the heads?

Good luck.

Zach

 

I dont know if this holds true for bike dynos's, but, I do know that with cars, you can get different numbers depending on the brand/type of dyno they are using. Maybe thats what your seeing? I also wouldnt be surprised if the maker of you kit padded the numbers just a little bit. I know someone here can confirm/deny this.

 

11 "pulls" for $30 & you were happy

 

I would also offer that Atmospheric conditions do, and will play a role. That said, I think your base numbers are not bad at all for a 98CI.