Dyno lines really jagged?

[Clipso 1]

I have been looking at a bunch of dyno sheets since I recently went to the dyno and I cant figure out why my lines are really jagged and broken up. I have changed the plugs, plug wires and coils and I even unhooked the msd just to check and nothing. The car wont rev past 6000 without breaking up really bad and hits a wall at 6200, so I have to shift at 5800 when raceing which sucks. My dyno sheet is under the dyno section of this web site. It made 396.5 HP and 360.60 torque which isnt bad on an all stock motor but I want to be able to rev to at least 7000. Any help would be really nice.

Thanks,
Jeremy

 

[andymoraitis]

I have been looking at a bunch of dyno sheets since I recently went to the dyno and I cant figure out why my lines are really jagged and broken up. I have changed the plugs, plug wires and coils and I even unhooked the msd just to check and nothing. The car wont rev past 6000 without breaking up really bad and hits a wall at 6200, so I have to shift at 5800 when raceing which sucks. My dyno sheet is under the dyno section of this web site. It made 396.5 HP and 360.60 torque which isnt bad on an all stock motor but I want to be able to rev to at least 7000. Any help would be really nice.

Thanks,
Jeremy

It's hard to tell without finding out what kind of fuel pump you have and what kind of timing maps you run, but I've seen this before with timing issues and also when a motor is starving for fuel. I would think that to make that much horsepower you'd be using an AFPR and a 255. If not, you could be seriously stretching the stock FPR which is only good to about 68 psi (base pressure and boost) according to the boys at NABR. Get us some more info and also let us know what kind of boost you were running, what kind of plugs and plug gap, etc. In hindsight, I'm wondering if those 680's are enough to push that 60-1. To me, those would be better sized for a 50-1 or an EVO III. I would have gone with 880's but that's just me.

Drop us a line when you can.

Andy

 

[Clipso 1]

Ok I got a 255 hih flow and I am using the stock regulator due to the fact my adjustable one wasnt working right. Im running 28psi. Autolite racing plugs gapped to 28. and taylor wires. I am actually pulling 40% of fuel from around 5000 up and the a/f ratio is at 10.8:1 but I didnt think about overrunning the regulator. Is there anyway to overcome the regulator with maybe less fuel and more timing? I guess I might need to buy a new one.

Thanks,
Jeremy

 

[biglady112]

Go to the dealer and get some new plug wire or buy some NGK's if you can. Try running NGK BPR6ES or 7ES's in your case. Those two might be a start. How old are the ones you currently have. The regulator will help. Not sure if that is your only issue, but your fuel pattern may very well be way off.

Steven

 

[andymoraitis]

Ok I got a 255 hih flow and I am using the stock regulator due to the fact my adjustable one wasnt working right. Im running 28psi. Autolite racing plugs gapped to 28. and taylor wires. I am actually pulling 40% of fuel from around 5000 up and the a/f ratio is at 10.8:1 but I didnt think about overrunning the regulator. Is there anyway to overcome the regulator with maybe less fuel and more timing? I guess I might need to buy a new one.

Thanks,
Jeremy

Jeremy,

I personally feel that you're out running the stock regulator and that she's starving up top, hence the jagged lines. 10.8:1 is fairly conservative and looks fine, but I'm concerned about the demand on the stock FPR. Even though you're overrunning it with the 255 and the stock regulator, 71 psi is a LOT to ask of that little guy. I'd get a fresh AFPR and also make sure that the rest of your fuel supply is strong by checking the fuel filter and fuel pump.

Another thing that doesn't feel right is why you'd be pulling -40 on the fuel maps with such a small injector above 5K. Are you running injector deadtime and global settings through the ECU with link or are you doing this another way? It almost seems like by removing that much fuel on what I believe is an undersized injector that you're starving up top when you need fuel the most.

As mentioned above, a fresh set of wires and NGK 7's may do you some good as well. I'm still thinking fuel more than anything else, but even with the MSD it could be spark. By the way, what kind of timing are you running up top when she starts to break up?

I'll be back late this evening, but I'll keep following this to see what you find.

Hang in there!

Andy

 

[Enraged78]

Jagged lines in a sine pattern on a dyno chart generally indicate knock. What's your base timing set to? What does your timing curve in DSMlink look like? What's your knock sensor seeing during the pull?

Matt.

 

[Clipso 1]

The wires and plugs were both changed while on the dyno, it helped but did not solve the problem. I have not had the best of luck with NGK's in the past, I used to foul out plugs in a weekend when i only had the safc so I started useing autolite and havent had a problem with fouling out plugs anymore. I am thinking of going to a COP system instead of buying another set of wires since i just bought these ones on thursday last week.
My base timing is whatever stock is and the timing curve above 4500 is on the stock curve as well. I show no knock currently, i had 2 degrees of knock at 5500 so I put the timing back to the stock setting and it went away.

As far as the injectors and my fuel stuff I installed a new pump and filter about 2 months ago. I know for a fact that the global is wrong on the link, but I was more concerened about my EGT when I set the global setting. I thought the car should only be at 900F while cruiseing, turns out I was told while cruising it can be as high at 1350F and no more than 1550F while beating on it. So I believe the global is around 14% to rich. But I believe the global doesnt affect the WOT sliders. I could be wrong.

How did you figure out it would be 71psi on the stock regulator, and more importantly which regulator would you use if you still have the stock rail. I had the Charged Air one but wasnt sure if it worked properly so I put the stock one back on and threw the adjustable one away.

Let me know what else I should try.
Jeremy

 

[andymoraitis]

Jeremy,

I don't use an AFPR since I only run a 190 pump and have all of my fuel control through my chip, but if I were going to choose one based on great feedback, it would be an Aeromotive or a Buschur/SX. Also, I'm calculating your pressure at the rail by adding base pressure and boost 43 + 28 = 71.

Let me know if that makes sense,

Andy

P.S. Why not call the guys at Buschur and while you're asking about the regulator, see if you can find out what they think. If you had a log, they'd really be able to hone in on the problem.

 

[steve]

But I believe the global doesnt affect the WOT sliders. I could be wrong.

How did you figure out it would be 71psi on the stock regulator, and more importantly which regulator would you use if you still have the stock rail. I had the Charged Air one but wasnt sure if it worked properly so I put the stock one back on and threw the adjustable one away.

The Global and deadtime adjustments are used all the time. The "WOT sliders" adjust the open loop fuel map which is a modifier to the calculations for fuel based on what fuel is needed for stoichiometric at the current airflow using the injector global, modifies the number based on the enrichment from the map and some other conditions and then adds the deadtime in.

The FP is easy to figure. Current FP = Base FP + Manifold Pressure. So under vacuum the FP is lower than base (it's 1:1 if you convert in hg to psi) and under boost it rises 1:1 with boost.

I'll be happy to take the old spoolinup regulator to use as spare parts for mine.

Steve