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Mph Vs Hp

Cjmartz2k

By Cjmartz2k,
in Engines & Forced Induction

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l0WRB Mentor

l0WRB

Posted
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cant figure out how to edit my post lol

r33 gtst

laggy kkr turbo

broken 3/4th syncros ( really hard 2 shift gears )

falken 225/50/16 tyres at 20psi pressure

full weight r33 with 80kg driver.

only rolled up 220kw on dyno but managed 115mph at willowbank, tuner said i really have somewhere round the 240kw mark.

this sound about right? cause some ppl with 300kw are only doin 116-117mph with good gearbox 2 shift into lol

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Cjmartz2k Proficient

Cjmartz2k

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Just to get my numbers out from the jumble of the first post.

R32 GTSt with the added weight of me (210lb), passenger (180lb), subwoofers in the trunk, and how ever much more an RB25 tranny weighs. How much do standard R32 GTSt's weigh?

11.8@124 (my slowest mph of the night) and a best mph of 127mph. No dyno though, but I've been told low to mid 500 rwhp.

Cjmartz2k Proficient

Cjmartz2k

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Hmm, that's about what I was guessing. It's a bit off from what Guilt-Toy was getting though. How does that jive with some of the dyno's you guys have? Also, what brand are you all using? I know dynojet's read REALLY high even for "american" hp, and mustang dyno's are supposed to read low.

Also, does the scale curve as the hp gets higher? Example (just making up numbers); if 300hp = 110mph'ish, and 400hp = 120mph'ish, does the amount of hp to get to 130'ish increase a lot more? There has to be a point where you get diminishing returns I would think.

Keep posting times/mph/hp/weight guys!

blow thru Contributor

blow thru

Posted
Posted
Hmm, that's about what I was guessing. It's a bit off from what Guilt-Toy was getting though. How does that jive with some of the dyno's you guys have? Also, what brand are you all using? I know dynojet's read REALLY high even for "american" hp, and mustang dyno's are supposed to read low.

Also, does the scale curve as the hp gets higher? Example (just making up numbers); if 300hp = 110mph'ish, and 400hp = 120mph'ish, does the amount of hp to get to 130'ish increase a lot more? There has to be a point where you get diminishing returns I would think.

Keep posting times/mph/hp/weight guys!

i have made 402rwhp a few monts back in a 32 gtst with rb20 an went to the track the other nite an went 12.90 115 with coilovers an wheelspin but car weighs in at 3256lb with stereo spare tyre tools an 3/4 tank of fuel.Will take out all those things an put standard rear shocks in to get the power down to the ground..

SLAPS Rising Star

SLAPS

Posted
Posted (edited)

Where peak power lands, how well the motor holds on to its peak power and gearing is a biggie.

For example.. An RB30DET with stock cams, stock inlet making 300rwkw+ where power noses over after 6000rpm isn't going to net a decent mph given the power its making. Along comes an RB25 with the same peak power that holds on to its power instead of nosing over - it runs a higher MPH.

Drop a set of cams in to the RB30, have it making the same peak power figure but due to the cams power holds on flat for near 1500rpm odd and up goes that MPH.

Edited by TheRogue
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted
Also take into effect power curve...

Really, it's the area under the torque curve that gets you down the strip quickest... :P

500RWHP Dyno queens are CONSTANTLY shown up on the strip by 300RWHP STREET cars... Purely, as the 500RWHP car has the worlds shittest power delivery...

300rwhp cars show up my car? hmmmm.. tell me where there is a 300rwhp r33 that does 11.11sec at 128 - 131mph ? and has a power curve like this. (torque drops from over 1000nm to 800ish nm by red line by most)

502.JPG

unique1 Mentor

unique1

Posted
Posted (edited)
300rwhp cars show up my car? hmmmm.. tell me where there is a 300rwhp r33 that does 11.11sec at 128 - 131mph ? and has a power curve like this. (torque drops from over 1000nm to 800ish nm by red line by most)

502.JPG

people with 300hp are the ones who say stupid comments like that :D i guess he thinks a 500hp car needs a gt45 to make the power lol. A 500hp car will smash a 300hp car everyday of the week im afraid unless your doing a carpark motorkana or something.

Also Anthony i reckon you would be making more than 500hp at wheels to run 131mph, the dyno must be pretty low reading if the car is a full weight r33

Edited by unique1
The Dan Grand Master

The Dan

Posted
Posted
300rwhp cars show up my car? hmmmm.. tell me where there is a 300rwhp r33 that does 11.11sec at 128 - 131mph ? and has a power curve like this. (torque drops from over 1000nm to 800ish nm by red line by most)

502.JPG

Was that run done in 3rd? Just noting the speed.

Nice work on the tune though, it looks like it holds near peak power for quite some time

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted
people with 300hp are the ones who say stupid comments like that :D i guess he thinks a 500hp car needs a gt45 to make the power lol. A 500hp car will smash a 300hp car everyday of the week im afraid unless your doing a carpark motorkana or something.

Also Anthony i reckon you would be making more than 500hp at wheels to run 131mph, the dyno must be pretty low reading if the car is a full weight r33

Yes that dyno was a Mainline dyno which is known to break alot of hearts with power read outs. Yes i know what its like to race my car around a small track, its not easy (hill climb)

Was that run done in 3rd? Just noting the speed.

Nice work on the tune though, it looks like it holds near peak power for quite some time

All my tuning is done in 4th gear, that run was stopped at about 190 - 200km/h. I only rev the car to 7000rpm because its a 3 litre and it only has a N1 oil pump which are known to destroy themself's when you rev them too hard. and stock rb25 balancer. at the track i rev it to 7200rpm

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Where peak power lands, how well the motor holds on to its peak power and gearing is a biggie.

For example.. An RB30DET with stock cams, stock inlet making 300rwkw+ where power noses over after 6000rpm isn't going to net a decent mph given the power its making. Along comes an RB25 with the same peak power that holds on to its power instead of nosing over - it runs a higher MPH.

Drop a set of cams in to the RB30, have it making the same peak power figure but due to the cams power holds on flat for near 1500rpm odd and up goes that MPH.

Kinda a bad example when a 30DET with stock cams doesnt nose over @ 6000rpm :D

But if you shift appropriately, then there is no reason it should be a lot different.

blow thru Contributor

blow thru

Posted
Posted
mine is a full weight R33, how much power should it have to run 131mph? I know the car has lots of torque. Whats the drag calc say?

Im assuming your car weighs in around 3300lbs? my old hk ute with a 400 chev made 545rwhp an went 132mph,now looking at the speed calculator at 3300lbs an 131mph your making around 560rwhp

Butters Experienced

Butters

Posted
Posted (edited)

You need to also take into account the 60ft. Its a good indicator of wheel spin which will up the mph.

Then also Peak HP means nothing average HP is were its at.

I have run(all diff cars) :

12.1 @ 116 mph 1.8 60ft in 1180kg car 280rwhp

11.4 @ 117 mph 1.5 60ft in 1140kg car 320rwhp

11.4 @ 119 mph 1.5 60ft in >1200kg car 400rwhp

10.89 @ 127 mph 1.49 60ft 1200kg car 420rwhp

10.35 @ 128mph 1.45 60ft 1130kg car 455 rwhp

As you can see the MPH to HP translation is not that simple. Especially when you look at the two 11.4s one car with 80rwhp more.

One was a peaky sl_ut other had power everywhere. Weight also played a big part.

Edited by Butters
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted
Guilt Toy. What exh housing are you using there?

1.06. but i do my own tuning and spent lots of time getting it right. So far all seems to be good :(

anyone got some decent drag tyres i can borrow for the weekend ? :(

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