Now that you mention it is a dynojet that makes perfect sense why the numbers so high. On a manual transmission setup, you should never use higher than 17% correction factor since they read so high. On loading dynos you can use 20%+.

Not to mention there is a lot of competition amongst Dynojet shop owners to pump up their dynojet adjustment factor even more as the dyno queens (supras, TT exotics etc) all want to set HP records. Choosing the right dyno makes a huge difference in that regard, especially since the correction factor margin of error increases as power increases exponentially (1000HP+ dynos can have errors of up to 100HP built into them on dyno jets).


At 17% 364 = 438hp (thats a best case scenario on the dynojet). Now if the shop fudged the dyno to produce better results then it could be as low as 15%. In that case, 364HP @ 15% correction factor = 428HP (most likely the most realistic scenario).

Eitherway, the actual number is not important for the purposes of tuning, its the CHANGE (aka the Delta) that matters most.

 

Agree that the change is what's relevant, but we don't have pre-mods numbers to compare to. Regardless, 364 whp sounds high based on the mods that have been done. Just sayin'.

 

I think this figure is actually too high.
I made more than 20 passages to bench the past two years and some figures are very wrong.
An example of my own experience, with the exhaust BR:
test on a dyno with the same preparation:
Bosch FLA 206: 390hp
Super flow: 414 hp
The difference is huge and both are professionals, but the super flow is more modern (2010).
What I did to "see" the difference in power in my changes:
in 3rd gear, stabilize the speed at 80km/h then thoroughly up to 120km/h and measuring time.
If someone interested in this idea, you can create a post above, I have a lot of measures in this regard. We can compare the time.

 

As a comparison from my v8v on DynoDynamics dyno:

Stock: 291
EuroCharged ECU + RPI : 336

So a gain or roughly 45 wheel HP (roughly 55 crank HP). But this is from a more aggressive custom dyno tune, not an off the shelf Aston mild reflash . However, this is still on stock air boxes and filters. 70hp is a bit extreme though. Perhaps with cats and filter on top of what I did 70hp would be possible, but not with the mods listed earlier in the thread.

Either way, until we see after numbers ... The baseline dynos are just meaningless numbers

 

007-What gear did they pull in for your dynos? I noticed that the gear made a big difference as third was in the 330's/340's and 4th at redline got up just over 360.

I had the same thoughts about the dyno, and had heard that dynojets were higher than some of the others but felt comfortable as the shop was recommended and other forum members that had posted dyno sheets were also using dynojets.

Either way, IF they mess with their dyno (was told they are a very credible shop) and 15% is the worst case, 428 is very strong over the stock 380 before the CATs.

Forum member CJ had 448hp at the crank without filters and a similar set up.

Per my post, the car feels even stronger now with the cats. Both the filters and cats combined have made throttle response a non issue in my car......and I bet they have leaned out the AFR. Thoughts?

 

Vince, I would love to see them if you can PM me. I have been looking at the manifolds.

 

Agree, no pre-mods to compare to. I will have post cats though.

At least its refreshing to be going back and forth for once on numbers we think are too high than the common "4.3 is underpowered and my dyno was weak". Again, I am not complaining.

 

Yes and regardless of what the numbers are, you've gotten a significant improvement in the way the car drives. At the end of the day that's all that really matters.

 

Always dyno in 4th on our cars. 3rd gear gearing is way too short and you will have significant drivetrain losses (hence lower readings). As a rule of thumb you typically want to dyno in the gear that is closest to 1:1 ratio to eliminate the transmission as a factor. Technically the optimal gear to dyno in is 5th gear, however most dyno shops don't feel comfortable pushing their dynos to such high speeds (some dynos max at lower rpms than cars can go to in their optimal gear.

With that sai I did one test run in 5th gear and the difference was only 3-4hp instead of the massive jump from 3rd to 4th. For that reason 4th gear is the safest alternative.

As far as the leaning out issue, they may have leaned out the mixture a little bit, but I bet you the AFRs are still WAAAY off. The only way to really fix that issue is retune the entire ECU with a true dyno tune. Leaning out will give you up to 13hp at the wheels, the rest of the gains are from other means (which I am not supposed to discuss).

I'm sure cats made a good 12-15 at the wheels depending on conditions and dyno. You should see significantly more torque in the mid-range as well.

Hope that helps,
007

 

The cats alone add about 12 hp to the wheels. I did a cats only before and after run in my "Cats Installation" Thread.

Anyone know if the filters add anything?

 

@Racer-I agree. Drove her today and the car feels so great. Kept blipping the throttle just to feel the improved response and growl!

@007-Thanks for the detailed response. That makes perfect sense

@CJ-I did not do a dyno pre filters, but I did notice the car rev ever so faster, and the throttle ever so slightly quicker. Of course this could all be in my head

 

Had the car on the dyno today for the post pulls after installing the cats over the weekend.

The RSC 200 Cell cats increased WHEEL hp from 364 to 375 and WHEEL tq from 288 to 304!

The gains were across the entire band.

For those of you who get dynojets done, I have all my files and can send them to layover yours etc.

I will scan dyno sheet later, here is the video of the pull. Car is much louder and lower in note.

 

So, we seem to be getting some consistency, cats alone will add 11-12 bhp at the wheels, thats about 3% extra power.

Its a good thing they make it sound better and give more torque, I'm not sure I'd ever notice a 3% increase in power, I certainly never notice a 4% increase in weight slowing me down when I've just filled the tank!

 

Correct-but both data sets are cars with power upgrade, exhaust and now filters. Not sure on standard cars, could be less, could be more. I was told combining these would equal a sum greater than its parts.

Where you feel the difference for certain is in the throttle response, the noise just makes the seat of the pants feel faster.

 

I was pretty damn close, said 12-15 hp & TQ 11hp & 16 TQ. Very good results.

It's amazing how mch deeper the exhaust not is afterwards, so much more deep bass to the exhaust note. The car sounds great!!

I would love to see a before & after comparison chart of both HP & torque to see where the largest gains were (ask the shop they can provide that for you)