not sure about the dyno theory. I thought chasis dynos are accurate cuz all the readings i see for peoples LS1's are in the 290's like you say. This is all over the country and i can guarentee that they used different dynos. why are all the numbers seem to be somewhat similar from dyno to dyno then? They got to be accurate and can calculate air temp/humidity changes and such.

Also whats the difference of mustang dyno and dynojet?

if dynos are so vague and inaccurate they why do we use them to measure power? Oh and i dont recall comparing dyno numbers to make ET's and such but that is an interesting concept. its all calculations which are never perfectly accurate.

I thought all dyno runs were measured from your 1 to 1 gear ratio. 3rd gear in most autos and 4th or 5th in manuals. Didnt think a converter would change readings that much cuz your still locked up during your run in your 1:1 gear at your peak Hp should be above your stall speed. torque peak should also be about at stall lockup speed or just over it so i figured it wouldnt make a difference.

But you learn something every day i suppose...

 

well they can calculate for different situations, but not for a turbo car. it was raare for a ls1 to make under 300hp on our dyno. you said.......

Didnt think a converter would change readings that much cuz your still locked up during your run in your 1:1 gear at your peak Hp should be above your stall speed. torque peak should also be about at stall lockup speed or just over it so i figured it wouldnt make a difference.

and i say....
but in reality(common sense is not sceince).......
it would be impossible for a car to make peak torque above a higher stalls lock up point.
lets see....torque converter,i.e. torque multiplier.
do this. run a car on the dyno....put a 3000stall in it.....run it again.
ive seen a 100tq to the wheel improvment. and just because you havent, that does not meen it does not happen.
example: my car picked up 25tq to the wheels going from a 2400 converter to a 2800 converter.

it made peak tq at 2000rpm.
with a 2800 stall!
not only that but not all stalls will lockup after the stall speed has been acchived. in reality almost everyone will never quit sliping.
you can manualy lock a converter on an ls1 and get 15-20hp to the wheels....only problem is this decreases the trans life incredibly.
stalls always slip.....so we are at the mercy of the power that is lost in the converter.

i was not trying to say that dynos are not a good piece of equipment to tune with or to get an idea, im just saying you can not base a cars performance from the power it makes on one.

oh and my theroy is just a theroy, im merly posing it to make you think about what your dealing with.
a dyno i.e. theroetical horse power, not acctual. its a test of what a machine calculates you are making and is best used for determining improvments from base line runs.
by the way looks like some one was trying to calculate et by hp numbers to the wheels and or flywheel........

quote......
wait a minute, you say that TTA will dyno 300rwhp. (Stock right?) Thats 375 flywheel horsepower assuming 20%loss. LS1's have 350 hp at most although rated at 305-320ish(same as vette motor) . a TTA is lighter than LS1 so it should outrun the LS1
But you say LS1 will trap higher? how is that possible. underpowered car that is heavier will not trap faster nor be quicker in the quarter. LS1 will consistently at 105-106mph and more. thats about right for 350hp or around that. If a TTA cant top that, then there is no way its putting out 300rwhp.
please clarify this for me
end quote
im not trying to rag on anyone or make them look stupid, i know all you guys are serious about your cars and i respect all of you and all of your opinions.....even calico's
i just hear things that are not right and want to dispell myths. i in no way think of my self superior to any of you.
i only ask that you consider what i have to say.
thank you,
junka junka junka

 

hey thats understandable vejatabul

about calculating et/mph times from dyno numbers. yeah there is a relation to what i said, but i wasnt going exactly by dyno numbers.

i simply stated that a car with supposively 300rwhp in a lighter body than ls1 cars, should outrun and more than likely stock for stock trap higher. i know it dont always work like that but with stock suspensions, there should be a difference. i was getting numbers by ET/ trap speeds and using online conversions to get estimated power. maybe thats the same thing as dyno, i dont know. but i dont think it is.
http://www.speedworldmotorplex.com/calc.htm
its fairly accurate, gets you an idea of what it should run LOL
based on my times, it says i got somewhere between 280and 290 on motor, which is probly a little high, but you get an idea. LOL

You seem like a very knowledgeable person and thats good to have around here. LOL Oh and there is a quote button to put quotes in your posts LOL

I dont know much about trannies and converters. I got an idea of what goes on but not the clearest. Whats that about not peaking above stall speed? My car factory is rated at 3200rpm peak torque. stock stall is 1600-1800rpms, so thats peak torque above stall. I put in a 2800rpm stall speed. it should still peak above that right? no other changes made, why would rpm powerband change?

 

To answer the original question...

ALL Depends on what he's getting.

My brother bought a GN in '87..BRAND NEW... 4 miles when he took delivery.

mid 14's UNTOUCHED, stock tires, etc etc.

Air bag in rear and some promaster street slicks netted 14flat several times , and came reallly close to breaking into 13's. This is UNTOUCHED motor wise.

Trick is building alot of boost at the line, and trying not to boil the tires rolling off the brakes LOL

He left it along and just drove the car. Bout a year later...we played again. With some simple mods and less than $200 invested the GN went mid 12's...

It's all about boost LOL

 

if you have a 2800 stall and you dyno your car than as soon as you hit the throttle it will make peak torque. thats just how it works and i tried to explain it but its just soooo much information. just take my word for it.yeah and the quote button.....ill start useing it

 

interesting how far we can stray from an original topic an on to a a tangent

 

It happens all the time on this board. Anywhoo, this thread is loaded with good stuff on the GN so I will leave it going providing we can keep it up.

 

lol naw i wasn't saying delete it...lol i like the gns keep it

 

would you care to explain how a motor making 1000hp is going to put down 800hp
and the motor putting out 100hp is only going to put down 80?

even more so if the drivetrain is spinning at the same speed?

if this is the case then lets say at wot with the wheels spinning at 800rpms the car puts out 10,000lbs of torque
20% loss means 8000lbs/torque

but lets give it only 1% throttle and now the car only puts out 40lbs/torque with the wheels spinning at the same 800rpms

so even though this drivetrain eats up 2000lbs of torque when at wot I can still drive it around town being the torque wasted isn't constant for the rpms it is percentage of power?

 

different dynoes use different means to mesure torque.
some use a load and mesure how fast that load accelerates.
others use a brake and see how much braking force is required to keep rpms the same
there are others that rather then hitting the gas and your rpms move up linear they have stepper dynoes that will let you rev up lets say 200rpms then hold then hold the motor there take a reading then up another 200 rpms hold the motor there and take a reading and so forth
all of these will give different types of measurements.

Quote:

if dynos are so vague and inaccurate they why do we use them to measure power?

they still give a good tool to base how much of an improvement this mod or that mod has made as well as tuning aids to see if I lean the fuel here do I make more power or less.
you try getting a partial tune on one dynoe and then move to another it's off to start over again for the most part

Quote:

I thought all dyno runs were measured from your 1 to 1 gear ratio. 3rd gear in most autos and 4th or 5th in manuals. Didnt think a converter would change readings that much cuz your still locked up during your run in your 1:1 gear at your peak Hp should be above your stall speed. torque peak should also be about at stall lockup speed or just over it so i figured it wouldnt make a difference.

even if you had your car in your 1:1 gear there is still a gearing bye the rear end.
so like 4th on my car is 1:1
but I still have an effective 4.10:1 gearing due to my rear end
also not all converters are lockup style. though I'm sure you already know that



But you learn something every day i suppose... [/QUOTE]

 

i dont know man..

all i know is that power is lost thru the drive train, ie, the tranny, gears, flywheel, etc. So a motor that makes 360hp on motor engine dyno will not put down 360 at the wheels on chasis dyno or whatever. typically the loss is anywhere from 20% to 10%. i just use 20%

 

I agree with that power is lost through the drivetrain.
granted the 10-20% I guess is the best we can do but I don't think it is a very good way to assume engine power

 

guess we just need track ET's and trap speeds then? sound good to you? LOL

 

I would agree...if I didn't have a stock car lol