My car currently runs 12.90's at the the drag strip. I had it on a mustang dyno, and it put down 220 rwhp/5400rpm and 225 rwtq/4400rpm. Don't these dyno numbers seem a bit low for the mods I have listed below?

CAR: ………………………………1989 FIREBIRD FORMULA
BLOCK:……………………………350 / 355 C.I.
COMPRESSION:……………….….9.6:1
HEADS:……………………………WORLD TORQUER 76cc 1.60/2.02 VALVES
CAMSHAFT:………………………COMP X-ENERGY 227/236 @ .050, .514/.524 LIFT, 112 LSA
PUSHRODS:…………………….….STOCK
ROCKER ARMS:…………………..COMP 1.5 ROLLER TIP
PISTONS:…………………………..SPEED PRO HYPEREUTECTIC DOME TOP
CRANKSHAFT:……………………STOCK
RODS:………………………………STOCK
THROTTLE BODY:………………..52mm TPIS
INTAKE:……………………………HOLLEY STEALTH RAM WITH RAM AIR INDUCTION
FUEL INJECTORS:………………...24 lb./hr. ACCEL
FUEL PUMP:……………………….GRANETELLI 255 lb./hr
IGNITION:………………………….STOCK/MSD COIL
WATER PUMP……………………..MEZIERE ELECTRIC
ENGINE MANAGEMENT:………...ADS CHIP
EXHAUST SYSTEM:………………1-5/8” EDELBROCK SHORT TUBE HEADERS/FLOWMASTER
TRANSMISSION:…………………..BOWTIE OVERDRIVES 700R4 STREET/STRIP
TORQUE CONVERTER:…………...TCS 2600
FRONT SUSPENSION:……………..LAKEWOOD 90/10 DRAG STRUTS
REAR SUSPENSION:……………….STOCK SHOCKS, LAKEWOOD CONTROL ARMS & TRACTION BARS
REAR END:………………………….3:73 BORG WARNER
WHEELS:…………………………….STREET, 17X8/17X9 CHAMP 800 CENTERLINES
STRIP, 15X3.5/15X8 WELD DRAGLITE
TIRES:………………..……………....STREET, FRONT 275/45, REAR 315/35 DUNLOP
STRIP, FRONT SKINNIES, REAR 15X11.5 MT, ET STREETS
FUEL OCTANE:…………………….93 OCTANE
RACE WEIGHT:…………………….3,450 lbs.
BEST ET/MPH………………………12.8/104 mph
BEST 60 FT………………………….1.85

 

Yes they do. That is why the track tells the tale. Here are mine for an example. 304RWHP and 334 RWTQ. 12.73@105.85mph. This is on a Dynojet.

 

Yeah the numbers at the dyno were not much more than the stock numbers on my firebird, and my car use to run 14.8 at the track. I asked the guy at the dyno shop "you mean to tell me my car is 2 sec. faster although I only gained 40 hp?" I was prettty dissapointed. But when I go to the dragstrip I'm pleased.

 

Dynos are for tuning. They're a tool, not a means of measuring HP. FWIW, Mustang dynos are notoriously inaccurate, especially the cheap belt driven ones.

 

Thanks for the input, I was told completely opposite.

 

mustang dynos are crap

 

Mustang dynos often read "low" compared to most others (Dynojet). Sometimes rediculously low. My brother's 87 GTA with a minirammed 400 put down only 260 HP to the rear wheels but ran 13.00000000001 @ 110.5 MPH on street tires. Go figure.

 

what track was that? ours won't give a 1/4 mile that detailed

 

From my research Mustang dynos are highly accurate, however, they also require operators trained properly. Obviously this one wasn't or didn't put in the correction factors or something.

There was an article a few years back that actually tested out verious dynos in the area and found the mustang ones were more consistant and more accurate. Maybe 5.0?

No matter who makes them though, if it isn't an eddy current dyno, don't bother. Inertial dynos are crap for accuracy, though they can be run consistantly far more easily.

And belt driven? I don't know of any Mustang automotive dyno that is 'belt driven'. They all use a single or pair or rollers from what I've seen. They do read 'low' compared to a dynojet because of the lighter roller(s). Their programming also comes with a feature to 'convert' to dynojet numbers.

 

I don't want to pick a fight, but I'm just curious how many people agree with your statement. I'd say a WBO2 used in conjunction with a dyno is a tool used for tuning for power, whereas a dynamometer is the instrument that measures the power output of the engine. Any comments?

And my $.02 that dyno is way off.

 

I've always heard that mustang dynos are very accurate but nobody likes them cause they don't read like a dynojet.


what sounds better 280hp or 220hp? seeing that everyone is going to use the one that reads higher and everyone gets used to those higher numbers and so when they see something that comes from the lower reading dyno it is deemed inaccurate.

maybe the dynojet just reads a little more optimistic in which case it is more inaccurate

 

Though the above statement does make a lot of sense, I would have to disagree in heat seeker's situation. 220hp and 225lbs/tq is obviously to low. That Mustang dyno has to be off.

Just for example, look at other similar cars, like an LS1 f-body. Many close similarities like weight, suspension, and rpm range (in respect to heat seeker's rpm range), and they are well known to be 300+ hp at the wheels. I have seen them run anywhere from 13.2-13.5 stock at 103-106mph. Granted, heat seeker has suspension upgrades, but the stall is still reletively small and the compression is pretty tame. Regardless, the trap speed is the biggest indicator of hp. Even given the slight weight advantage of the 3rd gen, 220hp is not going to be enough hit 103mph in the quarter. I would estimate somewhere around 275hp to the wheels.

 

on which dyno? mustang, dynojet or one of the many other dynos?

 

Any dyno other than the mustang dyno he went too.........
Those numbers are obviously too low. Shoot go to another mustang dyno that's set up correctly and a tech that actually knows what he's doing and he should hit 275hp. Go to a dyno jet and he may hit 315hp. Long story short......220hp and 225lbs/tq are bs numbers for what he is running.

 

You're right, no matter how you look at it a car w/220 rwhp does not run 12.80's in the 1/4. Not with the weight of my car including the driver(3,750 lbs). If somehow the numbers are correct then I can't wait till I put on my AFR heads.

 

there are some other things though to think of

one the boy hooked.
at least it seems to me he did since I don't notice too many people pulling 1.74 60 foot times
might be wrong there but as far as I know that is some getup and go
also what was the guy shifting at?
if he has a nice flat powerband that goes quite some way up there he should be able to wind it out a little longer in each gear letting the mechanical advantage make some torque to the ground before shifting to the next gear.
what does he launch at and stuff?

lot of variables though other then just peak numbers

though I will at least admit those numbers look a little lower then what I'm used to seeing also

anychance you can post a whole timeslip for us rather then just the end and begining numbers?
and what was the launch rpm and shift points?

 

And with a 12.87@105.83 My Dyno was 276RWHP / 391RWTQ This was also on a Dynojet

 

The Red Devil has dynoed the correct. You're probably closer to 280 RWHP with that trap speed.

 

rx7speed,

You are looking at his e.t., but that is reletively unimportant. His trap speed on the other hand is a direct result of hp. Times are deturmined by various factors, namely traction/60'time and gearing based both on the tranny and the rear end. Obviously torque plays a huge role in this, especially with a proper stall converter. However, after the initial launch, hp becomes much more improtant as the engine will only see high rpms for the rest of the run. Yes, hp is a measurement of torque. But a trap speed will better indicate hp and hp gains.

 

I have all my time slips at work so I won't be able to post them until monday. And I was wrong my 60. ft is 1.85, it used to be 1.74's with the TPI, but I lost a little torque with the HSR. I shift at about 5800 rpm. My trap speeds are always about 103-105 mph.

 

torque plays the factor for everything.
all horsepower says it how much torque you are putting out at a specific rpm.
horsepower doesn't make you go faster
torque does.


eh I donno. I just love playing devils advocate a little also

 

rx7speed, don't take this personally but I've got to make a joke... all in good fun

you know an awful lot about torque for owning an rx7

I'm just kiddin I think rotary engines are damn cool

 

I can tell

But like I said, even though hp is only a measurement of torque, it DOES play a critical role in speed. You define faster by track TIMES, which is fine, but many diferent factors play a role in that on top of torque. Torque converter, tires, gears, suspension/chassis all play a role in your TIMES. Simple example, take two cars with the exact same power numbers, leave car 1 stock and put tires, gears, TC, and suspension on car 2, and car 2 will smoke car 1 and have a much better time.. However, the trap speeds will be very similar to one another.

I am describing Speed by trap speed, which is a direct result of hp, or "upper rpm torque" if you want to look at it like that.
Take the example above. Except give car1 75 more hp but everything else completely stock vs car2 with traction and launch mods. They may run very close times to one another but car1 will have a higher trap speed.

That is why I say trap speed is a good way to measure hp and hp gains. You cannot measure torque the same way because there are too many other variables.

 

I'm going to tell you two more jokes also involving torque

first one.

I own a honda

second one. it has more torque then horsepower. and it peaks at 3000rpms

 

1988 350 TPI Formula- I was just making a joke about the 13.00000000001 ET on my brother's GTA. Actual ET was a maddening 13.01 or thereabouts. Oh so close to 12s, but not quite. My kingdom for just a bit more traction! All other comments I made in that post are factual (not jokes).

Here is the (screwy) Mustang Dyno printout from that car:



I wrote in the approximate RPMs myself since power vs. MPH reading means nothing to me. The torque readings seem "sane" especially when viewed against the car's actual performance in the real world. As for the horsepower numbers..... I'll just say that over 400 ft/lbs until about 5300 RPMs is a lot more than 258 HP in my book.

 

Keep in mind that all the dynos have many parameters that are operator controlled, such as adjusting weather station parameters, external corrections factors, and inertia compensation. Operators can change these parameters to artificially inflate HP.

We can clearly see this might be the case between Mkos1980 and 1989GTATransAm. Both have very similar trap speeds and ETs, but extremely distant HP/TQ numbers.

I wouldn't rely on a dyno for anything except as a tool to use for tuning, or for comparitive purposes (e.g. changing a part out and testing how much power it added over the original part). And of course, bench racing.

 

wait a second does this mean I can have a 800hpo honda that is bone stock?

 

I kinda figured but, me slow

 

i just worked for mustang dyno in twinsburg, ohio for 2 months. I can tell you from experience there are alot of operator controls that can be messed with. Many of the people that buy mustang dynos don't take enough time to learn how to properly use them. Mustang even trains the purchaser how to use the dyno if they so choose to pay for it, most of them don't. That is why many people get bad readings with mustang dynos, because the operator simply doesn't know what he/she is doing. As was stated before, if you aren't on an eddy current dyno, don't bother. Mustang dynos can be set to run in both eddy current and standard modes of hp and tq measurement. If the original poster takes his car to another mustang dyno with a properly trained operator, i'm sure he would get much better #'s. Also as stated, many people think mustang dynos are junk, simply for the fact they usually don't give you as high of a hp and tq reading as a dynojet will. And that right there makes most people think the dynojet is superior, most people want bragging rights with dyno #'s. The actual #'s mean nothing, it's the wideband readings and the charts that mean everything.

 

"I'll just say that over 400 ft/lbs until about 5300 RPMs is a lot more than 258 HP in my book. "

Thats true, because horsepower=(torque x rpm) / 5252 (I'm pretty sure its that exact number, but its around there if i am wrong). So if you are making over 400 ft/lbs at 5252 rpms, you should be making over 400 hp at that rpm as well. I never really understand those dynos that relate hp to mph, so I can't say where the error lies.

Also, there are alot of inherent problems with dynos. The biggest one I can think of is that they generally have a 10 mph fan blowing air in the direction of your motor, and when you're actually driving, theres obviously alot more. I believe this is one of the reasons that supercharged cars dyno so well, because they produce alot more power when oxygen is scarce (like at higher altitudes). I've also seen dynosheets where if a car was taken off the dyno and put back on at a later date, even with almost no change in temperature, there was a pretty big difference in power output (like 5-10 at the wheels). Thats why I think the real judge of power is how fast your car is from a roll. Thats my 2 cents.

 

here is a question
what rpm where they mesuring?
motor rpm?
wheel rpm? if that is the case they spin a lot slower then the motor
or maybe the rpm of the rollers?

 

what if I own a CRX gut the thing out take anything off I don't need and start replacing stuff with lighter weight parts
then I put a motor in there that puts out 160hp
take it up against a 64 lincon continental or something of that style car that is putting out 400hp at the wheels
the first car should be well under 2000lbs and would prolly book
but it doesn't have a lot of power
second car? it might move but doubt it would go very fast or anything
so taking your car from a roll isn't even that good either as a judge of power

 

pretty much all in all, hp and torque #'s don't mean crap on a dyno. A dyno is just part of a tuning tool, the other half being the wideband o2. It's all about the #'s you put up at the track. Track #'s relate to real world power and performance.

 

Yes, weight does factor in. But what I meant was that it doesnt matter how much power you are making if the car isnt fast. For the record, the most powerful feeling vehicle I've ever owned was a motorcycle that put out 90 rwhp tops.

I do disagree with track numbers being the ultimate judge of power. My friend has a turbo integra in which he has trouble running low 14's in because of traction issues, but he's taken lightly modified LS1's from a roll because of its great power to weight. I've also been in a mid 13 sec 3rd gen trans am that wasn't all that fast, it just had drag radials and drag suspension, so it really got going off the line. This is also why the new STI's and evo's are so fast, they have alot of traction, even though they have unimpressive power to weight. I guess it's all a matter of opinion though.

 

Why is there even a freakin debate here? Just go to the track and talk with the experianced guys and see what they say. And for the record, OF COURSE weight is a critical aspect!!!

Like I said before, you cannot judge power by times. There are too many variables involved (read above postings). However, you can use trap speed as a very loose indicator of horse power gains.

For example, throw some 17"x11" rims on the back with a set of slicks and a heavy duty steel drive shaft and flywheel. Now you've got plenty of traction, but a lot more rotating mass. Now race the same car with street tires, light weight 15"x7" rims, aluminum driveshaft, and an aluminum flywheel. The first setup will definetely run a faster e.t., but the second will trap higher. Why? because the second is making more rear wheel hp do to signifigantly less rotating mass. The first will have a better time though do to tires and a heavy flywheel to build initial inertia.

The general rule of thumb is 10 extra hp will equal roughly 1mph gain in trap speed. Like I said, it is a general rule of thumb, and applies for cars in the 3,000-4,000lb class. Obviously, the lighter the vehicle, the less hp you will need to see that gain. Heavier vehicles, like a full size truck however, will require more than 10hp to see a mph gain in traps.