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Dyno!?!.....

1K views 17 replies 11 participants last post by  scalbert 
#1 ·
Was off work today due to rain and decided to get in a dyno. Last Dyno was stock 212hp and 193.6 lb-ft. New dyno custome Magnaflow exaust plus AEM V2 intake.............first run 213.3hp 190.7 lb-ft, second 211.6hp 191.9lb-ft!!!????!! what gives....It was raining on and off and possibly humidity was a factor. When driving I know i feel a difference from the mods because my tires spin more in first and second. when i compare dynos(before and after)their is more torque in the low rpms now but if i compare the hp it actaully dropss a bit from stock and then spikes slightly at the end. The only thing I can think of is that th ecoputer was retarding timming to compensate for humidity??? Idon't know I 'll be bumbed out for awhile till I figure it out.
 
#3 ·
what was the SAE correction correction factor? And what was it on your stock run? If you saw a sudden spike then yeah, the ECU coulda been pulling timing. That can happen on extremely hot and humid days.
 
#4 ·
What if on every hot and humid day you just reset your ECU before you go to work, school, etc? Would that have any advantage? Plus I've heard about some people using the termometer trick, where you put a colder temp termo in it to trick the ECU into thinking it's 30-40F outside. I've heard it's harmless, but from more trusted people I've heard it hurts your car? Any clue on this SteVTEC?
 
#5 ·
If it's hot/humid out and you start to get detonation and timing gets pulled, resetting the ECU isn't going to change that after a reset. It's a physical property of the engine and weather. And those little ebay "IAT modules" are a good way to F up your car. If you jack the ECU into thinking it's 30F out yet it's 90F it'll run rich. But the O2's downstream will see that and adjust fuel trim. You'll have one confused ECU. It's a ripoff anyways. It's just a stupid little leaded resistor from radio shack which costs 5 cents maybe, but they charge you 5 bucks for it. lol

My thinking on this is that if the correction factors are way different then the comparison may be apples to oranges. Any CF from 0.95 to 1.05 should be reasonably comparable. But beyond that you're losing accuracy. The CF is just a calculation/estimate, and some engines are affected by weather more than others. So the more your CF is affecting your dyno, the less accurate and repeatable it will be. That's why it's always a good idea to still try to dyno under weather conditions that are as consistent as possible, even with SAE correction.
 
#6 ·
Hmm....I think I'll move to Bellingham, WA, just outside of Seattle. Temp goes from 30F at night in the winter up to 70ish F in the summer during the day!!! Talk about year-round track time haha.
 
#8 ·
stoner said:
Hmm....I think I'll move to Bellingham, WA, just outside of Seattle. Temp goes from 30F at night in the winter up to 70ish F in the summer during the day!!! Talk about year-round track time haha.

dont forget that its super humid in that part of the country! not to mention wet! but i've always loved washington, itd be sweet to move there.
 
#9 ·
BlackV62K2 said:
When I got my car dynoed, the correction factor was set to 1.17 =/. I dynoed @ 167.2 whp and 161 tq. Could that be the reason for such low numbers?
That was on a Dynodynamics dyno, not a Dynojet. So I'm not sure if your numbers were low due to dynodynamics just characterisitically being that way, or if it was due to other things. You'd need to know how other cars typically dyno on that type of dyno to really be able to compare.
 
#10 · (Edited)
chrisnick said:
dont forget that its super humid in that part of the country! not to mention wet!
And don't you forget that we are here in Florida........ we know all there is to know about humidity and rainfall. :yes:


And lightning too. The other night we had one of our typical nasty summer storms, and there were over 1000 lightning strikes in our metro area over a one hour period. :eek:
 
#11 ·
SteVTEC said:
what was the SAE correction correction factor? And what was it on your stock run? If you saw a sudden spike then yeah, the ECU coulda been pulling timing. That can happen on extremely hot and humid days.
Those numbers are SAE corrected. Same stock.

There was an SVT 390hp ford pick-up that was using the dyno before me for about 3 plus hours. Could that have effected the dyno unit at all. I just can't see how I made absolutly no power with my mods. One thing to mention I am getting exceptional gas milage......maby my engine is running lean?? Without a check engine light. I possibly need a stand alone air/feul + timing controller.
 
#13 ·
HOW exactly does the 7g ECU "adjust" to your driving habits? Link/evidence/proof?
 
#14 ·
heh, a lot of times things really do learn, but people think they adjust to driving habits when in reality they adjust to weather conditions and wear..

a lot of people think the transmissions in my avenger and dynasty are adaptive to driving style, when in fact they're only adaptive to wear.. so that they shift comparably at 150k to what they did at 15k.

after i pulled my dynasty out of the weeds after sitting for 6 months it seemed slower.. maybe it was adjusting to being stationary?? jk.
 
#15 ·
The easiest thing to do is to get an OBD II scanner tool (i.e. Auterra) and monitor your ignition timing while you drive. Then find out the best weather condition (temperature, humidity) by finding out when you get the best timing advance. After you figure out the best condition, take your car to a dyno on a day you figure has the best conditions and record the timing during the runs. If the timing matches or is close to what you monitored to be the best, your getting the most HP/TQ out of your engine that is possible on that dyno.

I think S.A.E correcting it will do the same thing I mentioned above but where is the fun in that? :D

03LXV6Guy said:
And don't you forget that we are here in Florida........ we know all there is to know about humidity and rainfall. :yes:


And lightning too. The other night we had one of our typical nasty summer storms, and there were over 1000 lightning strikes in our metro area over a one hour period. :eek:
Florida is like the most humid place on earth right after the rainforest (exaggeration) :p . But here's a fact, we are the #1 place in the world for lightning strikes. I was driving down the highway yesterday during a really bad storm and lightning was striking down all over the place :shudder: .

SteVTEC said:
HOW exactly does the 7g ECU "adjust" to your driving habits? Link/evidence/proof?
I don't think it can. I know some automatic transmissions can adjust to driving habits but Honda's/Acura's can't.
 
#17 ·
S.A.M6 said:
Could that have effected the dyno unit at all. I just can't see how I made absolutly no power with my mods. One thing to mention I am getting exceptional gas milage......maby my engine is running lean?? Without a check engine light. I possibly need a stand alone air/feul + timing controller.
No, the dyno was most likely not affected by the previous vehicle.

Why do you assume that you should be making more power with those two additions. Granted, I would have expected something from the intake but then again, may not any more. The J30A4 seems to be pretty well tuned out of the box and I really wouldn't expect anything from the exhaust. Heck, I only gain less than 4% on my car with an open exhaust compared to running through the factory pipes and this was up at 370 WHP. You may have swapped items which provide no real benefit.

However, I still think the intake would have shown a 3 - 5 WHP gain.

We also do not know the details. What were the correction factors or at least the ambient conditions during both sessions?? Temperature can play a part but is corrected for in the dyno software. However, it does not account for timing changes which could be at play here. Humidity can affect performance but is also corrected for. Plus, high humidity would cause the car to run a bit richer which helps to remove the notion that it induced knock.

You engine is not running lean and you do not need a controller; you don't have enough done to the car to warrant that.
 
#18 ·
TH23 said:
Considering that the ECU adjusts to your driving habits, you should reset your ECU and drive a little bit harder than normal before you hit the dyno.
No, this car does not. He has a manual transmission so there are no adaptive algorithms for the transmission control except what is in his head. The ECU does adapt to changes in the A/F ratio only during cruise or part throttle. But that is hardly under his control and is not dependant on driving style.
 
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