1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Racing Beat exhaust dyno compairisons

Old 05-14-09, 09:12 PM
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Are the 5th and 6th port accuators working? Just wondering because your car makes good torque on the low end. Also you should consider makind a ramp in the sleeves for better flow if you still have them in and since you can weld. Idk, it should help.
Old 05-15-09, 01:18 AM
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No. It's running an IDA carburetor how are the 5th and 6th ports going to work? lol. It has the sleves still in the engine with pineapple inserts. I wasn't ever a fan of the inserts, but they're in the engine when it was built, so I just left them. I guess in theory they work. I spent today porting the intake manifold. I'll be back on the dyno on the 23rd. Maybe this weekend if I can get a slot.
Old 05-15-09, 01:19 AM
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Originally Posted by Hyper4mance2k
No. It's running an IDA carburetor how are the 5th and 6th ports going to work? lol. It has the sleves still in the engine with pineapple inserts. I wasn't ever a fan of the inserts, but they're in the engine when it was built, so I just left them. I guess in theory they work. I spent today porting the intake manifold. I'll be back on the dyno on the 23rd. Maybe this weekend if I can get a slot.
The 5th and 6th ports should not be effected by a carb swap at all

Unless you have a new lower intake as well?
Old 05-15-09, 01:26 AM
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You can't run an IDA carb and any part of any stock manifold.
IDA manifolds for reference.

Old 05-15-09, 01:32 AM
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Originally Posted by Hyper4mance2k
You can't run an IDA carb and any part of any stock manifold.
IDA manifolds for reference.

Ahhh. Gotcha. Those look expensive
Old 05-17-09, 09:29 PM
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Originally Posted by Hyper4mance2k
Will a car drive with a 2" exhasut? yes, but I gaurentee you can't make more than 140 ftlbs of torque na with it. and there's no way to make peak tq past 5500 rpm with it.
Uh, about that... my peak torque is in the 6000-6500rpm range (don't have a dyno sheet scanned, sorry) as measured on Defined Autoworks' dyno and peak torque was around 120 at the wheels, which is a bit over 140 at the crank, no?

And later it did 170whp on a dynojet but they couldn't get a torque readout, their RPM readout dealy thought 8500 was 7000, or 14000, for some reason.

Anyway that's with a chambered muffler and 12A midpipe...

Which is all going away soon, the muffler looks like a dumpling
Old 05-17-09, 09:30 PM
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Originally Posted by Starfox07
Ahhh. Gotcha. Those look expensive
The manifold's the cheap part
Old 05-18-09, 03:50 AM
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Originally Posted by peejay
Uh, about that... my peak torque is in the 6000-6500rpm range (don't have a dyno sheet scanned, sorry) as measured on Defined Autoworks' dyno and peak torque was around 120 at the wheels, which is a bit over 140 at the crank, no?

And later it did 170whp on a dynojet but they couldn't get a torque readout, their RPM readout dealy thought 8500 was 7000, or 14000, for some reason.

Anyway that's with a chambered muffler and 12A midpipe...

Which is all going away soon, the muffler looks like a dumpling
Sorry, I was suggesting aproximate limits for street ported 12A's and wheel hp and wheel tq. Almost noone here has the ability to measure flywheel hp, and guesses at drivetrain loss are exactly that, guesses.
Old 05-18-09, 05:17 AM
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Having read through all this and it being well past 6 in the morning here, I have no idea if you made mention of lightweight flywheel, or if you have a high performance clutch and pressure plate as well. If you've not done those mods then those should net you a bit higher of a horsepower gain.

To all of you who are talking as though he should be able to just **** out 15 more horsepower out of nowhere, apparently you've never attempted to make a damn-near perfect setup even better. Hyper's setup sounds like it is extremely well planned out and executed.

Hopefully porting out your intake manifold raises your power a significant amount as well.

Also, good luck with hitting your 200 horsepower mark. Count me in for updates.
Old 05-18-09, 11:40 AM
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Why don't you just port your motor? Didn't you say its basically running on cleaned up stock ports?
Old 05-18-09, 12:38 PM
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Originally Posted by Hyper4mance2k
Sorry, I was suggesting aproximate limits for street ported 12A's and wheel hp and wheel tq.
Ah, okay, I thought we were discussing 13Bs. (And yeah I know mine's a 4 port, not a 6 port, but oh well)

And sorry for the confusion - when I see HP and ft/lb I think of real measurement not wheel measurement.

Almost noone here has the ability to measure flywheel hp, and guesses at drivetrain loss are exactly that, guesses.
Well, given number of people who HAVE taken engines off of engine dyno and put them in-chassis and measured on chassis dyno, we have enough data to make educated guess. Roughly speaking, it is about 15% give or take a little bit. My 170whp would then correspond to 200hp, which dovetails nicely with my peak duty cycle (95%) and AFRs (about 12.7 at peak HP) given that I'm running two 680cc injectors. It also meshes well with my trap speed in the quarter mile (97mph, with a 2700lb car/driver combo).

Whoever said FC naturally get lower numbers than FB because of heavier drivetrain wasn't thinking too clearly. FC N/A and FB have the same rearend, same transmission. Main difference is the rearend has four CV joints in it and the wheels have some camber/toe, which isn't going to change readings THAT much.
Old 05-18-09, 02:01 PM
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Well I have a 13B, but someone asked about his 12a and that was what I figured one could possibily do with a stock midpipe.
As far as minimumizing drivetrain losses. I had a steel lightweight flywheel and clutch on the car, but the clutch took a **** on me 2 weeks ago and I now have a shiney new aluminum flywheel and 4 puck race clutch in, so well see if that helps. I also ported the intake manifold this last week, so well see how it goes.
Old 05-19-09, 12:58 AM
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To the OP, just for me can you please back up your 190rwhp with a timeslip and movie of the drag run. Seeing as its a 2444pound car with 190rwhp I am expecting a trap speed around 110mph. GOOD LUCK because I don't believe the numbers.
Old 05-19-09, 09:11 AM
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110 mph? Where did you get those numbers from?
Old 05-19-09, 10:53 AM
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Originally Posted by Jobro
To the OP, just for me can you please back up your 190rwhp with a timeslip and movie of the drag run. Seeing as its a 2444pound car with 190rwhp I am expecting a trap speed around 110mph. GOOD LUCK because I don't believe the numbers.
Ouch....
Old 05-19-09, 12:39 PM
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Nice work Hyper. Now if we only had a Mindtrain exhaust we could throw on a dyno...
Old 05-19-09, 01:35 PM
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Originally Posted by Jobro
To the OP, just for me can you please back up your 190rwhp with a timeslip and movie of the drag run. Seeing as its a 2444pound car with 190rwhp I am expecting a trap speed around 110mph. GOOD LUCK because I don't believe the numbers.
He got them from out of his ***, or from a quartermile calculater online. I'm 260, the car wet is 2440 with a 12A, it's got a 13b now, total the car should weigh w/me about 2750, so with 190whp and a strong enough tranny I might, might make it to 100mph in a 1/4 mile. MIGHT... This saturday, if you actually read the thread, I will be going back to Intec to rerun against the origional run of 138whp so I have a direct compairison against the origional Dyno. I've gone through 2 transmissions now, so I don't drag race my car. It's set up for autoX it's not a drag car. Infact last time I went to the strip I snapped the output shaft clean in half. Anyone in the NW can vouch for my car, and the dyno sheets.
Old 05-19-09, 02:36 PM
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Indeed we can. If I'm not in Canada that day, I'll be there and even get video of the runs if you want.
Old 05-19-09, 02:47 PM
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Originally Posted by Hyper4mance2k
Well I have a 13B, but someone asked about his 12a and that was what I figured one could possibily do with a stock midpipe.
As far as minimumizing drivetrain losses. I had a steel lightweight flywheel and clutch on the car, but the clutch took a **** on me 2 weeks ago and I now have a shiney new aluminum flywheel and 4 puck race clutch in, so well see if that helps. I also ported the intake manifold this last week, so well see how it goes.
my last gsl-se i switched from the RB short header/presilencer/muffler to the 'street port system'

the street port made way more low end power, but peak HP seemed like it was close, the SP system having a little more, BUT the short header/stock midpipe made its hp at a higher rpm.

the SP system peaked in the low 6200-6500rpm range, the short header was more like 6800

its not apples to apples, as you have pointed out, the RB single is like 1.75" in at the muffler and the sp is like 2"
Old 05-22-09, 03:40 AM
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I'm a big boy too 240pounds myself!

Even 2800pounds wet, and 190rwhp aka 255bhp, you should be trapping spot on 105mph. I have a feeling thats where I'm going to land next time I race my 12AT.

I've got dyno sheets from mates with 13BT's on 13psi showing less hp than your car, but the thing is, these cars back up the HP at the track and run a 13 flat.
Old 05-22-09, 04:12 AM
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God man, I hope this isn't an insult, but are you origionally from the States? I though only redneck americans were obsessed with dragracing. lol. I don't drag my car anymore it gets too expensive. I've broken 2 tranny's now, and I'm taird of pulling them. Don't worry Saturday I'll take pix and video of my car on the Dyno. 190whp is more like 237bhp with 20% drivetrain loss. Plus this was on a Dynojet. I know somepeople are die hard Mustang Dyno fans.
Old 05-22-09, 09:34 AM
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The stock 3rd gens were rated at 255 hp at the crank. They dyno'd between 215-220 rwhp. I'd expect a 190 rwhp engine to be putting out around 225 or so. That's it. You don't lose as much as you think you do through a drivetrain.

If you lost 65 hp through the drivetrain, it's got to go out in the form of heat. Where is it going? That's a ton of energy. Consider how hot your cooling system gets from an engine that at cruising speeds (180* or so) is only producing about 15 hp and then tell me where 4 times the energy could possibly be dissipated from in a drivetrain. I don't see it.
Old 05-22-09, 11:27 AM
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Originally Posted by rotarygod
The stock 3rd gens were rated at 255 hp at the crank. They dyno'd between 215-220 rwhp. I'd expect a 190 rwhp engine to be putting out around 225 or so. That's it. You don't lose as much as you think you do through a drivetrain.

If you lost 65 hp through the drivetrain, it's got to go out in the form of heat. Where is it going? That's a ton of energy. Consider how hot your cooling system gets from an engine that at cruising speeds (180* or so) is only producing about 15 hp and then tell me where 4 times the energy could possibly be dissipated from in a drivetrain. I don't see it.
Na's seem to loose more. part if it is, that an NA makes peak power at higher rpm, more rpm = more losses. prime example is the rx8, doesnt mazda claim a 20% drivetrain loss? 232flywheel *.8 = 185.6. 255 * .8 = 204hp...

example number 2 is not valid, as the thermostat regulates the tempratures. we run an integra @ the 25 hours of thunderhill, and at night when the temps are 20F, with no thermostat it runs so cold, we blocked off the whole radiator with cardboard. and this is running full load 80% of the time.

that being said, you're not wrong, 65hp is a lot of energy... lot of heat, lot of noise , something like 2800 BTU/min
Old 05-22-09, 11:56 AM
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Originally Posted by Jobro
I'm a big boy too 240pounds myself!

Even 2800pounds wet, and 190rwhp aka 255bhp,
More like 225hp.

I've got dyno sheets from mates with 13BT's on 13psi showing less hp than your car, but the thing is, these cars back up the HP at the track and run a 13 flat.
Either your dynos read low, or your dragstrips are not 1320 feet long. I've long noticed that ET and MPH from Australia never seem to "jibe".

Most cars running 13 flat are quite a bit faster than 105mph.
Old 05-22-09, 12:02 PM
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Originally Posted by j9fd3s
Na's seem to loose more. part if it is, that an NA makes peak power at higher rpm, more rpm = more losses. prime example is the rx8, doesnt mazda claim a 20% drivetrain loss? 232flywheel *.8 = 185.6. 255 * .8 = 204hp...
More seal losses, but in the RPM variance we're concerned about, the difference through bearings and gears is probably a wash. More speed but less torque being transmitted.

that being said, you're not wrong, 65hp is a lot of energy... lot of heat, lot of noise , something like 2800 BTU/min
And yes transmission fluid and diff fluids get HOT. That's why endurance racers need coolers for them.

I remember a test of some kidwank car (McLaren F1?) where at the end of a top speed run, the differential temperature warning light came on.

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