Help my analyze my dyno numbers

deftsound · Jul 24, 2007

Well I made 363.38hp and 368tq on a dynojet. I was expecting closer to 400 mainly because I thought I had an advantage because of my longtubes. I would have thought with my existing mods that I'd get atleast 380...

Anyway its the stock 3.6" pulley at 6psi and with a fresh royal purple synthetic oil change. Also the car was a little heat soaked because it was the 4th run that we got the numbers from but that was with 15min breaks in between with a fan blowing on it and I have my doubts as to whether that could effect my numbers by as much as i feel something did

What can I do to get to 400?

I've been thinking that maybe my stock 2 1/4" catback is restricting the exhaust flow as well as the stock plenum/TB....I just feel like I should be making more...

Also my passenger upstream 02 sensor is dead, my tuner told me that it wouldn't be effecting performance but part of me is skeptical...either way im fixing it tomorrow

blkhorse · Jul 25, 2007

I don't think thats too bad for 6psi,9 psi should give you what you want

ADRENLN · Jul 25, 2007

yea, 6 psi is low and you were on a mustang dyno....your numbers are goog for your mods. thats prob 380 on a dyno jet. so yea, drop a pully size or 2 and you will have 400 hp!

deftsound · Jul 25, 2007

ADRENLN said:
yea, 6 psi is low and you were on a mustang dyno....your numbers are goog for your mods. thats prob 380 on a dyno jet. so yea, drop a pully size or 2 and you will have 400 hp!

wait...i think it was a dynojet, it says dynojet research at the top of the dyno sheet ...wow thats a real kick in the ass

Anyway heres a picture of the dyno sheet, sorry its kinda hard to see

Dusstbuster · Jul 25, 2007

Your stock 2 1/4" exhaust IS holding you back, get that fixed and you should see some nice gains too. Also that 02 sensor might be messing with the #'s a little bit too...

deftsound · Jul 25, 2007

Dusstbuster said:
Your stock 2 1/4" exhaust IS holding you back, get that fixed and you should see some nice gains too. Also that 02 sensor might be messing with the #'s a little bit too...

I guess i just have a hard time believing that 1/4" increase in exhaust pipe diameter would help much, maybe I could justify getting a 3" catback though...

Dusstbuster · Jul 25, 2007

deftsound said:
I guess i just have a hard time believing that 1/4" increase in exhaust pipe diameter would help much, maybe I could justify getting a 3" catback though...

Surface area is exponentially related to radius though.

2.25" exhaust has a surface area of 3.97 square inches
2.5" exhaust has a surface area of 4.91 square inches, allowing much better airflow.

PLUS aftermarket exhaust is usually mandrel bent so there are no narrowings when the flow hits a curve, whereas your 2.25" crimps down when it curves so the flow is restricted even further.

deftsound · Jul 25, 2007

Dusstbuster said:
Surface area is exponentially related to radius though.

2.25" exhaust has a surface area of 3.97 square inches
2.5" exhaust has a surface area of 4.91 square inches, allowing much better airflow.

PLUS aftermarket exhaust is usually mandrel bent so there are no narrowings when the flow hits a curve, whereas your 2.25" crimps down when it curves so the flow is restricted even further.

awesome thats what i wanted to hear, now i can justify spending 400$ on a catback

El Diablo · Jul 25, 2007

More boost and you'll be at 400hp...maybe 10 or 11 #'s

Dusstbuster · Jul 25, 2007

deftsound said:
awesome thats what i wanted to hear, now i can justify spending 400$ on a catback

Do you have a 2.5" midpipe? If not you'll also need to upgrade that too

Matt's 03 GT · Jul 25, 2007

The real question here is "How does it feel?"

deftsound · Jul 25, 2007

Matt's 03 GT said:
The real question here is "How does it feel?"

it feels great, i definitely need gears to get into the power band though

stangbanger01gt · Jul 25, 2007

I would be apprehensive about adding more boost on the stock block. Are you aftercooled? I think 6 lbs. is playing it safe. Save yourself from the headache of having a ruined motor b/c of too much boost! do the catback, tb, plenum or aftermarket intake (bullitt,trick flow,p51, etc..) that'll give you some more power on your FI motor for sure!

stangbanger01gt · Jul 25, 2007

deftsound said:
it feels great, i definitely need gears to get into the power band though

3.73's

ADRENLN · Jul 25, 2007

oh crap! yea itd a dynojet. well honestly its still not bad. i think the average from what i have seenover the years is. if you have a stock gt and throw a blower on it, they will make about 350 rwhp. this is will the 99-04 gt. HOWEVER, this is the kicker. that is usually with 9psi!

that being said, i think you mods and l/t's are helpingyour power. you are making more then a regular gt at less psi. this means if you equal up the boost to the average level 8-9 psi, you will be a good amount ahead of them. the other mod, x pipe catback, and plenum...will help too. those 3 mods alone with a tune will get you around 15 - 18 rwhp!

deftsound · Jul 25, 2007

yea i noticed those dyno numbers in the dyno thread, i guess im right on par being at 6psi

goshia · Jul 25, 2007

The longtubes are only going to gain you about 2-5HP.

As you can see in my sig I am running 11PSI pulley to get 400HP that is actually only hitting 8.3PSI here in the Mile High City area.

deftsound · Jul 25, 2007

goshia said:
The longtubes are only going to gain you about 2-5HP.

uh not sure where you heard that from but thats bull****, you must be thinking of shorty headers

and yes the midpipe is 2.5" and its catless

ADRENLN · Jul 25, 2007

yea, my l/t added 15rwhp peak non aspirated. this was a before and after dyno of just the l/t's. so they will add atleast that with a power adder.

DBMSTNG · Jul 25, 2007

deftsound said:
I guess i just have a hard time believing that 1/4" increase in exhaust pipe diameter would help much, maybe I could justify getting a 3" catback though...

it's not just the size of the pipe. it's also how smooth the bends are and how the internals of the muffler are shaped.

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