The other day a friend of mine and I went to have our cars dyno'd at a local place. The dyno was a MAHA dyno that used to be used for emissions testing purposes.


I have a 6-speed 94 Z28, at the time the only mods were SLP CAI, TB bypass, 160 stat, and fanswitch. I made sure to dyno in 4th gear. On my first pull, I was a bit disappointed because my car only put down hp in the 230's range, there was no torque number registered (which seems weird since I thought the software would calculate hp from the measured torque ). The dyno operator suspected that there might have been something wrong with that first run. Then I did it again after letting the car run a bit, and it was a bit better, I put down 246 WHP@4460 RPM and 308 WTQ@3420 RPM, I will have the graph soon to post. The person at the dyno told me that the 2nd run was better since the engine was warmed up.

From those figures the hp number seems a bit low, but the torque looks about right at the low rpms. The numbers would suggest that the torque drops off significantly in the higher rpm range. I was maybe a bit disapointed because here I read about stock 6-speeds putting down 250's-260's hp bone stock. Maybe a change of plugs & wires would help since they're still the original ones.

Also for comparisson, my friend who dynod the same day has a A4 94 Z28, with free mods, ram air box, mac mids & y-pipe, no cats, flowmaster muffler, upgraded ignition, and PCM4less tune. He put down consistant runs of 260's HP and a impressive 325 lb-ft TQ! Here the hp seems also low compared to what similarly modded cars here are getting, but the torque seems to be there.

 

Might be the dyno machine. Are the numbers SAE corrected? If not, whats your elevation?

 

Sorry I forgot to mention I'm at sea level.

 

Ok then. But still the weather conditions of the day still may have had an effect on your numbers. If the dyno was corrected, then these weather conditions wouldnt be factors and your numbers would be comperable others considering the amount of modifications.

So do you know if the numbers were corrected?

If it was previously used and made for emisions testing, i would doubt that it would convert the runs to standard

 

all sifferent manufactureres dynos will read differently...my guess is that dyno reads a bit low compared to a dynojet which is what most people use...

 

Next time start your pull with a normalized 3000RPM's( hold it at 3000 until the rollers catch up-- 20-30 seconds) then pull it about 200RPM's past redline before letting off.You may see a big differance

 

I held it at 2000 RPM's in 4th for a few seconds and then went right to full throttle. The car pulled all the way but I stopped before redline (about 5200 rpm) because they were telling me to cut it since they were noticing that the hp had reached it's peak and was starting to fall off on the dyno graph.


I don't know if the numbers were corrected though

 

The dyno operator told me that they had a mustang cobra on their dyno at one point and then the same car went on a dynojet and apparently the numbers were within 1% of each other. They told me it's pretty comparable to a dynojet.

 

You need to start higher in the RPM's and give your stock engine a run at the roller's.Your peak HP RPM may go up a tad and be a higher figure.
Make sure you have a good operator that has done plenty of pulls and he can help you get it to max,if you ask.

 

I am the friend with A4 that dynoed my car with MTL_Z28 and I guess most people are dissapointed when they go to the dyno and see the real #s but My car traps 106 and with weight of my car I thought I would have put down closer to 300Rwhp but I also have a knock sensor problem causing a ses light so that could be part of my problem, what do you guys think?

I put down 262rwhp@ 5004rpm and 326 tourque@ 4339rpm.
94A4 and my mods are in my sig. (runs where with out NOS of course.)

 

Yeah it doesn't make sense that your car traps in the mid 100's but yet only put down 262 whp on the dyno Although the torque is definitely there. These numbers would suggest that both your car and my car die down in the top end alot.

 

The MAHA is made by SUN, and is listed as an eddy-current type dyno. That makes it similar to the Mustang, rather than the Dynojet. Hot Rod magazine had a comparison of 5 different dyno types a month or two ago, and the difference in RWHP for a 200HP Mustang GT was only a few HP between the Mustang dyno and the Dynojet. The Mustang dyno was lower.

 

Also knowing your plugs and wires (and perhaps filters etc) are old is a big deal. Keeping it tuned up would possibly help. then I'd say get some headers and a cat back, tune it and re-dyno. I bet you'll like the numbers a LOT more.

Edit: 14,669 Posts! Good lord!