Gained 23 rwhp with LT Headers (see dynos)

01mgvert · Jun 19, 2004

Attached are the before and after dyno charts for my 2001 Mustang GT. My stang now feels and runs like a real muscle car. I was excited that I gained 23 rwhp with the Hooker LT headers and o/r x-pipe, but I was disappointed with the base number: 222.8 rwhp. I always thought that a stock Mustang GT dynoed at 224 rwhp, which allows for a 16% loss from crank horsepower (260 bhp) through the transmission. This would mean that all my previous mods reduced my rwhp by 1. And yet I decreased by 0-60 mph time from 6.1 seconds to 5.3 seconds using a G-Tech. The 16% transmission loss must be for a manual transmission. Does anyone know the loss for an automatic transmission?

007 · Jun 19, 2004

Its about 15% manual and a ****ty 20% for us auto guys. My dyno numbers are on the low side too (no idea if they are SAE or STD or what though...)

007 · Jun 19, 2004

Nice gains. It'd be nice to plot the runs side by side to see the gains at dif rpms... got the raw data?

The 4.10s hurt your dyno numbers slightly too.

01mgvert · Jun 19, 2004

007 said:
Its about 15% manual and a ****ty 20% for us auto guys. My dyno numbers are on the low side too (no idea if they are SAE or STD or what though...)

If a 20% loss for an automatic is correct, then a stock Mustang has 217 rwhp, assuming 260 bhp. This would mean that my Diablo performance tune, Steeda underdrivey pulleys, Accufab 75 mm tb & plenum, C & TrueFlow inlet pipe, K & N filter gained me a whopping 8 rwhp. This still doesn't make sense. I know that these parts gave me more than 8 rwhp. Not only did I feel SOTP gains, but my 0-60 mph times went down subtantially. (Please don't give me grief about the 0-60 mph times. I haven't had time to take my car to the 1/4 mile track).

Johnlas · Jun 19, 2004

i have read on here that the 4.10 gears will make you lose like 1 or 2 hp so maybe thats it?

BigHairyMonkey · Jun 19, 2004

try more like 3-5

~Stangzorized~ · Jun 19, 2004

Those numbers seem pretty low. I've seen numerous people on this board dyno over 260rwhp with those mods with a manual transmission, not really sure about the automatics, but I wouldn't think that you lose THAT much through the drivetrain...

01mgvert · Jun 19, 2004

BigHairyMonkey said:
try more like 3-5

With a 3-5 rwhp loss with the 4.10 gears, my previous mods would have added only 11-13 rwhp. Does this seem possible?

doveman · Jun 19, 2004

my car dynoed 232 rwhp on a dynodynamics dyno with O/R x-pipe and borla exhaust. havent got a chance to dyno it with the long tubes on it but im lookin for about 20 more ponies. those gears are a little much for an auto, i wouldve recommeded 3.73's but then again that is my opinion.

98SteedaStang · Jun 19, 2004

Whats SAE or STD? With all my mod except for the headswap I dynoed 189rwhp. I thought after my mods I would have around 200 but no. After the heads I have 215rwhp. I really, really need a tune. I plan to do long tubes and an off road h-pipe soon, then comes the SCT tune.

03trubluGT · Jun 19, 2004

doveman said:
my car dynoed 232 rwhp on a dynodynamics dyno with O/R x-pipe and borla exhaust. havent got a chance to dyno it with the long tubes on it but im lookin for about 20 more ponies. those gears are a little much for an auto, i wouldve recommeded 3.73's but then again that is my opinion.

From what I've seen, LTs will only give you 10-15 HP over what you have if you have an offroadX already. Of course you will have to get the shorty offroadX to match the LTs.

I gained 23 RWHP and 19 RWTQ (peak gain) with my exhaust combo over stock. The torque gain was about 12-19 through the ENTIRE powerband (no loss whatsoever) and the HP gain was about 5-10 to begin with and climbing to 23 peak gain.

Matt

01mgvert · Jun 20, 2004

98SteedaStang said:
Whats SAE or STD? With all my mod except for the headswap I dynoed 189rwhp. I thought after my mods I would have around 200 but no. After the heads I have 215rwhp. I really, really need a tune. I plan to do long tubes and an off road h-pipe soon, then comes the SCT tune.

I'm also curious about the difference between STD and SAE. I noticed that the performance shop completed my baseline dyno with STD horsepower but my modified (headers) dyno with SAE horsepower. Are we comparing apples and oranges here? Does this mean that the headers did not really net me 23 rwhp?

Dark Knight GT · Jun 20, 2004

01mgvert said:
If a 20% loss for an automatic is correct, then a stock Mustang has 217 rwhp, assuming 260 bhp. This would mean that my Diablo performance tune, Steeda underdrivey pulleys, Accufab 75 mm tb & plenum, C & TrueFlow inlet pipe, K & N filter gained me a whopping 8 rwhp. This still doesn't make sense. I know that these parts gave me more than 8 rwhp. Not only did I feel SOTP gains, but my 0-60 mph times went down subtantially. (Please don't give me grief about the 0-60 mph times. I haven't had time to take my car to the 1/4 mile track).

UHM? You need to do your math better. 20% of 260 is 52. Deduct that, and you have 208, not 217. You also have to remember that 4.10 gears can cause a dyno read low by a few rwhp. So techincally, you gained about 20-25rwhp with those mods. The 75mm throttle body probably did very little, if anything for you. The plenum, pullies, and tune probably gave you most of that.

01mgvert · Jun 20, 2004

Dark Knight GT said:
UHM? You need to do your math better. 20% of 260 is 52. Deduct that, and you have 208, not 217. You also have to remember that 4.10 gears can cause a dyno read low by a few rwhp. So techincally, you gained about 20-25rwhp with those mods. The 75mm throttle body probably did very little, if anything for you. The plenum, pullies, and tune probably gave you most of that.

This means that I gained 15 rwhp with my induction mods (plus performance tune and underdrive pulleys) and 22 rwhp with the LT headers and o/r x-pipe. This seems reasonable to me. I still wonder why the baseline dyno was done in STD horsepower and the modified dyno in SAE horsepower.

StangLou · Jun 20, 2004

STD #s are a little higher than SAE #. Your shop for some reason gave you a higher start hp # then switched after your install. that is very odd. most will stick with std to std. it as least lets you compare your results before and after. id complain to the shop and maybe they will give you another run at it std so you can see what your car actually gained.
also another tip for on here... people like sae #. i got flamed so many times for post my #'s std its rediculous. both #'s use correction factors, but sae #'s take a little more into consideration.

Jackie Chan · Jun 21, 2004

wrong thread

nickthegenius · Jun 21, 2004

The header haters must have finally left the site. I can't belive that this has been here this long and Mustanglife or oogtdude (IIRC) haven't jumped in about how good stock manifolds are.

BTW, nice gains I have Mac LT's but I have no idea what kind of gains I got because I never had a "before" number.

01mgvert · Jun 21, 2004

For my father's day present yesterday, I went driving around. I put 150 miles on my newly modded stang. What a blast. The car pulls strong from 3000-6000 rpms and then slowly returns when decelerating. Although an expensive mod, it was surely worth the expense.

StngStr · Jun 21, 2004

Father's Day gift = driving around in your car?

Guess it's father's day everyday for me. And I don't have any kids!

01mgvert · Jun 21, 2004

StngStr said:
Father's Day gift = driving around in your car?

Guess it's father's day everyday for me. And I don't have any kids!

If you had a 14 year old son and an 11 year old daughter (sibling rivalry), you too would enjoy alone time in your car. This was the perfect gift: A time of peace and quiet, as well as the exhilaration of acceleration.

Gained 23 rwhp with LT Headers (see dynos)

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