Thanks that makes a lot more sense, so basically you saw some gains but know for a fact that the car was not properly tuned and so the dyno numbers are not a true representation of the headers capabillities.

I can understand that and it is clear. I think your prior post today may have been misinterpreted in its meaning. I have to admit that this cleared it up quite a bit for me

 

An example of the inconsistency of the dyno pulls. Comparing TXGS's GS430, with a factory torque rating of 325tq at 3400rpm vs. Halo's best pull on his GS400 factory rated at 310tq at 4000rpm, Halo had 75rwtq MORE at the supposed 430s PEAK rpm of 3400rpm.

Do you think this is because TXGS's car is just weak? Absolutely not. This dyno operator was not able to properly load the cars and the range was all over the map below 4600rpm.

We need more and repeatable TUNED dyno info before we know more.

 

I completely agree with jbrady. I was far from impressed with the equipment and the operator. The wide ranging results of the dyno runs between the 3 cars lends suspicion to the accuracy of the results.

I for one would like more hp and torque early so I can burn the crap outta my tires

 

I guess what I was getting at is a big time company would have more of a controled test and would have probably used the best techs, equipment, and multiple cars to come up with an estimated increase... just not going to happen in this situation...

Closest would be for like 4-5 GS4's getting these on and meeting up somewhere experienced (SRT) and doing some runs without and then with tuning...

Any takers? Anyone know if Mo would be interested... should only help his FI projects...

 

Right.

Well if thats how it was then might as well just disregaurd the dyno results completely cause thats a retarted difference. I would not even waste time by going there again.

 

OK heres my 2 Cents. 1st Thanks to JB, Gawd, and Halo.
Heres how I see the fact of this testing and results and what we have learned..

1. We needed accurate before ( Baseline ) and after ( Change ) runs. The standard is not just HP and TQ but, is like car ( same Engine / same mods) averages. Temp and Conditions, Humidity, Type of dyno and type of readings.
2. A/F ratio, Trans gear pulls were made in ( Auto 2nd or 3rd) one to one gear is best.
3. ECU history resets done when, check engine light resets etc. Wheel spin and tire pressure which if very over inflated can reduce load and increase HP falsey.
5. Dyno facillity and operator and operators knowledge on like cars or Motor.

IMO:
I don't know what all of Gawds mods where. Did he have a CAT Back Who's Manufacture ? Comparing a GS 400 to a GS 430 ( bigger Bore ) is not good for me. What where Halos Mods ? Any
No Temp in Dyno room #. No Humidity in Dyno room #. A/F on 1 run, no A/F on next ?

That we got an increase at all is very good but... this test to say this is what it does is Inconclusive.

I have a personal opinion about what it takes to take this very well designed Header to 25 + HP on a NA 400 motor and some know what it is. I'l take the Headers and think they will do just fine if they close to fit on my 97 SC400.

 

Okay... after reading all the information on they dyno results and procedures used to obtain them, I think the data is inconclusive. At present my GS400 (engine wise) is bone stock. My headers are on order and I plan on going to get my car dynoed soon to get a good baseline for myself and the CL group. I will be testing on an in-ground dyno at Adrenaline Motorsports in STL, MO. My buddy owns the shop....so I will try to see if we can get many pulls done.

IMO... for accurate results we will need the following:

Dyno with competent operator.
Wide-band O2 for a/f ratios.
Properly inflated tires.
Decent dyno conditions.
Multiple pulls.

When dynoing....I will have my tires checked, hopefully 80 degree temps, bone stock car that is running fine, and a properly hooked up Wide-band.

Inbetween runs... I will install headers and reset ECU and drive the car for one week with varying driving conditions/styles to let the ECU get adjusted to the headers. Then I will wait for similar conditions as the first dyno day and hopefully return and make sure all variables are as close as possible to the first run except the addition of the headers of course, then perform the dyno runs and hopefully get good results.

If anyone has anything to add to this post or if there is anything I have missed then please feel free to comment...

 

I have two thoughts here. Short and sweet.

1. For any one person's testing, I would hope that they are using the "corrected" numbers. We can only hope that the dyno operator's have properly set their system. Using corrected numbers should mostly alleviate before/after runs and any air temp or humidity changes.

2. The drag strip does not lie. MPH tells HP. (now, here you WILL need similar air and temp quality in your before and after testing.)


(yeah, yeah, the drag strip won't exactly tell us seat of the pants feeling, driveability, etc. )

 

jbrady - I agree that getting consistent, representative and meaningful data out of dyno pulls seems to be difficult, if not impossible unless the gains are really dramatic (like adding FI or nitrous for example). I posted a thread about my own last dyno results (here) and it wasn't clear what gains I got from SAFC-II tuning either really the peak numbers at least were better after tuning. And we were doing A/F tuning.

 

Yes, getting consistent numbers out of any dyno session is a very hard thing to do indeed. Even with my 7 runs at each dyno session, there were definite fluke numbers that would throw off any definitive answers that could be extrapolated from the data given. Although a median baseline can be had, you still have to factor in variables such as OBD II correction, engine heat, operator error, etc....

 

I tried to keep the variables as similiar as possible, all mods were the same as baseline readings. Halo's mods are just the SRT intake..

 

i'm ordering on the next go around, but one quick opinion question. Will we need to go with a afc2 and remove the srt unit? If we can find someone to tune correctly, it should yield alot more power. On the dyno, did they start out in third gear? I was asking a few dyno people and we were discussing the gear to start out in, and well third was the one he recommended.

 

Yes, the numbers were "corrected" however, corrected data makes certain assumptions the key being that the engine being tested cannot change its own parameters based on temp and pressure variables. It is true that THEORETICALLY corrected numbers should allow direct comparision. However, if your engine changes A/F or timing or any other variables as a function of its factory design then a simple atmospheric correction factor will not include these sometimes large variables.

If you look at the performance change based on pressure and temperature alone it is not enough to offset my measured gains at the racetrack in my car. What seems simple is not usually so.

 

So whats going to happen now? Are they planning on doing another dyno run?

 

Are we ever going to see these dyno charts even if they're inconclusive?