Carl Johansson

Anyone have horsepower and torque curves for a stock 88 with an Automatic trans. I need to do some gear calculations!

Carl Johansson

Aurora40

I believe the owner's manual has one.

CentralCoaster

Calculations are for nerds. What are you trying to figure out. I have more calcs than einstein.

Trans wont affect it, the 4+3 was as inefficient as the auto, if not more so.

Carl Johansson

I am trying to calculate what rear end would be the most beneficial to us for Bonneville with an 88. So I need to know max HP rpm. from there I'm assuming i could look at theoretical speeds with the 2 different rear ends - then look at horsepower required to go that fast - then I would know if the car could pull the big gear. I could also figure out how much HP I will need to add if I can't pull the gear.

Carl I don't think I'm a nerd - but sometimes I play one on the internet!" Johansson

65Z01

Go to my site, click on the label below the pic of my '88 and scroll down to the 1st Dyno Pull listed. You will see what mods had been done.

Since the intake was pretty much stock at that point the dyno shape should have been pretty much stock though power was higher.

Carl Johansson

The only dydno pull I could find was after mod IV - the HP maxed out at about 4600 rpm - but that was after a ram intake on mods II or III - so I'm not sure how that would have affected it!

Thanks,
Guys like you who keep impecable (where did the spell check go?) records sure help alot of us slovenly guys out!

Carl Johansson

mrc24x

If you are just looking for a dyno run here is my completely stock '88 engine without a/c or air pump. Hooker long tubes through 3"duals/flowmaster 40's were the only add ons. It is a 4+3 w/ 3.07 rear. Kuhmo 315/35/17 V710's (25.4" Dia.)

Carl Johansson

Thats what I needed. looks like max HP is 4600 rpm, that is consistant with other things I have seen, so i will go with that number!

Thanks
Carl

cv67

Stock 89. Catback, frisbee removed

vettet80

my vette is 88 with the 3.07 rear automatic but i dunno why it dynos much lower on hp. torque is higher than yours though.

dynojet best out of 3 runs i got 216 hp at 4200 and 338 tq 2800.

Wheelman

Have you checked your timing? You can shift the hp/tq readings on the dyno around slightly by playing with your timing....Stock should be 6* BTDC

Slalom4me

It wouldn't hurt to hedge and bump the peak HP 200-300 RPM back down
from 4,600 when running the numbers for a TPI intake configuration.

.

Carl Johansson

Yah - thats what i was thinking ken,

i will use 4400 and do the calculations - that may be a moot point if we go to HSR -

BTW - I do have an MSD6A ignition and HEI with the built in coil on top of the distributor

Carl

vettet80

my timing is exactly at 6. my motor knocks when its set higher than that.

LT4BUD

So what happened on your recent 142mph runs?????

What limited your speed??? What rpm and gear etc did you top out??

Tell us more..

Per Corvette Action Center, the 1988 was rated 245hp @ 4300 rpm

So if you peaked out at 4300rpm on your recent runs, you are there...

vettet80

when i topped my car out at 149-150 mph the tach was 4300-4400 rpm so yeah i guess im up there at its max hp. makes perfect sense!

Carl Johansson

More than likely just ran out of room. it was still pulling - but not hard! I can't tell you RPM - I was in a 25 mph crosswind - the streamliner that ran ahead of me got knocked over - a couple of roadsters flatspun - so i was more interested in horizons and finding the finish line - than in checking RPM.
The trans is a700R4 - and it was in 4th - i guess thats an 0.70 OD - if i remember correctly.

Next month we will have the video camera mounted in the car - looking at the dash - so we will know for sure - But I'm betting we didn't get to 4200 rpm in 4th.

carl Johansson

Carl Johansson

assuming 4300 rpm
with a 28" tall rear tire
and a 4th gear ratio of 0.70 (700R4)

with a 3.08 rear end we would be clocking 166 mph.

If we drop it to a 2:59 rear end we will be going 197.5 mph

The trick is - it takes alot of HP to go fast = so even with the correct gearing - we are gunna need big ponies.

Using a frontal area of 19.8 ft sq
a CD of 0.3
to go 200 mph - i would need 340 HP just to overcome the wind resistance - and another 85 HP to drive the speed - so given enough time - if you gear it right you could make 200 with 425 hp rear wheel! (perfect dead on gearing ratios)

In comparison to go 150 mph - using the same inputs - only requires 145 HP to overcome the aerodrag and another 35 ponies to drive the speed - so to go 150 would require about 185 rear wheel HP

see I told you that wind resistance is the 800 lb gorrilla of landspeed racing!

Carl
Carl

mrc24x

My guess is that I'm giving up a little tq with 1.75" headers and 3" exhaust but it seems to let it breath a little higher. Not too shabby for 194000 miles.

65Z01

OK here are some numbers from my '88 Owner's Manual:
RPM....CHP....Torque
800.......40......250
1,600...100......290.....HP/Tq cross point
2,400...145......320
3,200...215......340.....peak Tq
4,000...235......305
4,200...245......280.....peak HP
4,800...235......250
5,600...185......200.....both HP & Tq interpolated

These are the best numbers I can get from a plot that is 1 3/4" x 1 1/4"...