Grand Am Dyno 160 WHP

[SappySE107]

Ok so that isn't exciting...its just sitting there:P

http://wot-tech.com/Dyno/dyno%2012-14-12%20001.jpg

Link to a huge pic of the dyno sheet. So I want to discuss this because that dip near the end is odd. It got worse with each run even when I changed fuel and spark (to which we found where it likes the spark just fine 2 degrees less than before KR). Its about 10 seconds in so I want to go through the code and see if there is anything special about that time frame, or roughly 4800 RPM

The car has to run the 28# injectors. We hit 73% duty cycle on these runs, and even though we am commanding 9.3:1, its running 12.3ish (that is where its happiest, not mid or high 12s). Absurd, but the normal driving and idle are pretty damn good and the wideband reads 14.7-15.2 most of the time, which looks fine to me. It doesn't matter what is commanded, only what is real, so I am happy with the results even though it puts our "Before" numbers much higher than the normal 143 WHP results I see for these cars. More to come, just a matter of figuring out what we want to do first. Port work is simple...headers would be nice. Also would like to compare 56mm vs 65mm on the ported set if we can get that setup.

[unchained01]

That's not bad for stock and some tweaking
Thanks for posting !!!!

[Superdave]

what RPM were you running it up to?

[SappySE107]

5400 is when he let off. We were commanding 3rd gear with HPTuners and it was noticable when it hit that dip, as well as when it was starting to drop in power.

[Superdave]

hmm, I haven't had any 3400-autos on the local dyno (that i remember anyways). All the Jbody swaps I run up to 6300 ish in 3rd gear, usually the graphs are smooth.


I wonder if it's trans related.. Did you happen to try a long pull in 4th?

[mfuller]

Good numbers. Now I know my car isn't making the power it should.

[SappySE107]

No, we didn't do 4th gear. We haven't raised any shift points over stock either so that could be part of it. Matt, this car is goofy. Its been a huge PITA for KR for a year and still requires a ton of fuel where everyone else is good on stock injectors. We don't know where the fuel is going but its not black smoke like I would expect. Its using enough fuel for over 200 whp right now.

[Mars]

I hate it when dyno operators don't take the extra 3 seconds it takes to select the right setting so that the RPM signal is correct.

Pretty much a mild cam is like a 35 - 55HP increase with these motors which is cool.

[SappySE107]

mild cam and 55hp? 35 is overly generous. id expect 15 hp from our street cam and no other mods. Perhaps you meant with other mods? Either way, we haven't done a cam comparison yet to know for sure.

[unchained01]

No, we didn't do 4th gear. We haven't raised any shift points over stock either so that could be part of it. Matt, this car is goofy. Its been a huge PITA for KR for a year and still requires a ton of fuel where everyone else is good on stock injectors. We don't know where the fuel is going but its not black smoke like I would expect. Its using enough fuel for over 200 whp right now.

Wow that is goofy I hope you get it figured out Since i dont have a HPtuner (I have a DHP) I cant comment too much but i know there were posts about sensor desensitizing Maybe Greg can chime in here And confirm or deny if it was an added option

[SappySE107]

We had 31 degrees of timing at 5500 so its not the knock sensor or computer pulling the timing out. The wires arent new so we will start there for the dip in power where it should have peaked.

[unchained01]

Ah i see Yeah now tracking down what isnt "healthy" may be a real journey in its self
I hope it is something quite simple I
would like to see this progress step buy step Good Luck !!

[SappySE107]

We have replaced a lot of parts on this car already, since we demodded it to get our baseline. Bearings are good, oil pump is new, crank scraper installed, new rear main seal and oil pan gasket. Still need to check the timing chain but that isn't making noise and the powerband looks perfect. Cleaned injectors (also cleaned stock to make sure that wasn't it). Holds pressure at WOT so its not the new pump. Filter is 2 years old so that is also next. Plugs are stock 3500 ITR4A gapped to .045", new air filter, fresh oil and filter. We swapped to another stock transmission and torque converter because we thought we had a problem before, but it turned out to be the settings for the trans in the tune. I didn't know they were changed, or set wrong but it presented a terrible KR after shift issue. Added a trans cooler, trans temps were 150s consistent. Air intake temps were in the 80s and lower 90s.

[unchained01]

Sound like your getting really close to pinpointing it !! I am anxious to see what the cause really is also

[Superdave]

Wow, 31 degrees... I've never been able to put more than 28 to a stock 3400 w/o a few knock counts. Cool though, it must be nice to have a baseline car to build off of!