Wait, according to calculations i should have about 350hp from a 305TPI, AM i wrong?

Subscribe
Aug 14, 2001 | 03:52 PM
  #1  
see sig below, i did some calculating, and figures show that at the flywheel i should have 354.32hp, does that sound right, and its including without any power adder, i though with all the work i've done it should be more, anyone else have any guesses or idea why my hp and torque should be at???

------------------
92' camaro
New 305 block TPI conversion, Flat top pistons,Bore over .30 Forged parts all around,Edelbrock intake,ported plennum,ported corvette alluminum heads, accel cam,52mm throttle bodie, SLP runners Home aid cold air induction, Air foil,ford SVO 19lb injectors,fuel regulator,cloys timing chain, comp alluminum roller rocker arms and pushrods MSD 8.5 mm wires, bosch plattinum plugs, hypertech cap & rotor and coil, Edelbrock TES headers, free flowing catalytic converter and a 3 inch force II flowmaster exhaust system, and a 3 inch cutout,Zoom multi friction clutch, T-5 tranny,billenstien shocks&struts.
Soon to come!!!
Procharger system 12lbs o boost.
New paint job(hawaiin orchid purple)Cast alluminum ZR1 rims w/ 275 tires.
site to see my cars at <A HREF="http://www.geocities.com/iroc_dis/iroc_dis_page.html
Other" TARGET=_blank>www.geocities.com/iroc_dis/iroc_dis_page.html
Other</A> car;
1971 plymouth Duster
Mods:340,edelbrock victor jr. intake, 650 4 barrel holley, heddman headers,40 series dual flowmasters, cold air intake,4:10 gears, just got a new paint job and cragar rims with 315 tires in the back.
:Yeah its not a chevy but damn how many 71' dusters have u seen in the streets.
Reply 0
Aug 14, 2001 | 04:05 PM
  #2  
Without knowing what cam you have its a little tough, but 355hp for a 305 sound good!

------------------
91 B4C 305 TPI - SOON TO BE 383
TREMEC 5-SP, STOCK 1-BOLT REAREAND w/342 GEARS, K&N, AIRFOIL
EDELBROCK HEADERS, DUAL CAT TO HOMEMADE Y-PIPE & 3.5" SINGLE PIPE W/ FLOWMASTER, CRANK PULLEY, MSD, FUEL PRESS REG, COWL HOOD, WELD WHEELS
14.1@ 98MPH
-------------
OTHER RIDE
67 CAMARO - STREET CAR, BIG BLOCK, PUMP GAS
350TH w/ATI 10", 12-BOLT w/373 GEARS
10.92@125.2 1.55 60FT. ON MOTOR - ET-STREETs w/MUFFLERS
Reply 0
Aug 14, 2001 | 06:31 PM
  #3  
Flywheel HP means nothing and without putting it on a dyno guessing what it puts out is just that. A guess.

Weigh the car with you in it and as much fuel as you want to race with. Make a pass down the 1/4 mile and get your best mph. From that you can easily calculate how much HP is getting to the rear wheels. To measure torque you'll have to use a dyno.

------------------
Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley
Reply 0
Aug 14, 2001 | 06:58 PM
  #4  
Where did you come up with that number from? I have a real hard time believing it myself. Do you have track times or chassis dyno numbers or other real-world data that it was derived from?

------------------
"So many Mustangs, so little time..."
ICON Motorsports
Reply 0
Aug 14, 2001 | 09:45 PM
  #5  
the cam im using is the lingenfelter/Accel cam part #74211, i calculated my hp using a simple device, a Calculator.
Reply 0
Aug 14, 2001 | 10:41 PM
  #6  
A calculator... Do you mean you took the stock hp rating and then added on the hp rating of each performance part? Like '215 hp stock + 25 headers + 40 cam + 10 air foil'? If that's how you did it then, yes, you probably are wrong. Those advertised horsepower ratings are not accurate at all. The best way to get an estimate would be to either take it to the track or dyno it.

------------------
91 Z28
Come see The Vicious...
Reply 0
Aug 14, 2001 | 11:10 PM
  #7  
Once again i am proven wrong like an idiot, i didnt exactly go by hp figures as estimated,close though very close, i guess the best way to find out is a DYNO, cant wait
Reply 0
Aug 15, 2001 | 09:22 AM
  #8  
I pushing 350 HP with my setup, so I'd expect close to the same or less with yours. CHP did an article with the same setup I have and dyno'd 409 HP. The latest CHP did a 305 400 HP buildup, but haven't put it on stand yet. Check it out.

------------------
'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 A&A snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp
Reply 0
Aug 15, 2001 | 11:18 AM
  #9  
One obviuos clue to your horsepower is the injector size. You can only produce as much HP as is available from the amount of gasoline you can get into the motor. AFAIK 19 lb/hr injectors only flow enough gasoline for somewhere around 250 or 260 HP tops no matter what else is around them.

With properly sized injectors and programming to match, you might get 285 out of that setup.

------------------
"So many Mustangs, so little time..."
ICON Motorsports
Reply 0
Aug 15, 2001 | 01:47 PM
  #10  
RB83L69, I read in a book on TPI that "according to TPI Specialties, they have used injectors for a stock 305-inch TPI engine on engines over 400 cubic inches with no problems." I'm assuming they had an afpr with it, but surely that's good for more than 285 hp. But when I built my 355 I opted to upgrade to #24s anyway.

------------------
91 Z28
Come see The Vicious...
Reply 0
Aug 15, 2001 | 04:27 PM
  #11  
What I don't get is that HP in not a real measurement, torque is! Hp is calculated from torque figures, when you graph hp and torque they alway cross at 5250 rpm (I think thats the number). They cross at the rpm no matter what combo you have, thats becuase of the calculation. My question is, if you can run you car on the 1/4 and figure hp, why can't you reverse the math and get torque. I am not a math major so I may not know what I am talking about

------------------
1988 L98
Vette Heads/no EGR
SLP Headers/Y-Pipe
ARAP bin
Reply 0
Aug 15, 2001 | 07:02 PM
  #12  
you calculated your hp??? and to think i was going to use a dyno. you said you were proven wrong like an idiot and that's a bit harsh, but what did you expect from a post like this. you can't give hp numbers from a parts list. you could build an engine for example with the performer rpm equipment exactly as they did and not match their hp as not all engines are identical. even the desk top dyno's and g tech numbers are mearly a calculated guess and no more.
Reply 0
Aug 16, 2001 | 04:14 PM
  #13  
Quote:
<font face="Verdana, Arial" size="2">Originally posted by z28dan:
My question is, if you can run you car on the 1/4 and figure hp, why can't you reverse the math and get torque</font>
I think you could.... sort of. If you made a bunch of runs and figured out your opptimum shift point, you would know roughly where your hp peak is. You could then figure your hp, add 15% to get FWHP, then do the hp formula backwards, and you would have your roughly estimated torque, at that peak hp rpm . So you wouldn't know your peak torque, but you could get a pretty good number for torque at peak HP.

One other thing you could try, and this is a real wacky idea. Go to the track and shift at the RPM you think your combo makes peak torque. Say it's 3000 RPM. Make a few runs w/good launches, and quick powershifts @ 3000 RPM. Then do the HP calculator, add 15% to get FWHP, the do the hp formulw backwards. I don't know how well this would work, but it would be interesting experiment for someone to try that has real dyno numbers to compare it to.

[This message has been edited by Tom 400 CFI (edited August 16, 2001).]
Reply 0
Aug 16, 2001 | 04:57 PM
  #14  
It still wouldn't work, HP is a measure of the ability to do work over time, torque is an instantaneous rotational force independent of time.
Reply 0
Subscribe