2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Major HP loss! Avg 104 HP!

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Old 06-13-05 | 01:02 PM
  #1  
PerkyStina's Avatar
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Thumbs down Major HP loss! Avg 104 HP!

...So I went to a dyno run this weekend, to find out what kind of HP I was getting.

Well...

1st run: 98.98HP, 112.23 Torque
2nd run: 107.79HP, 115.17 Torque
3rd run: 107.82HP, 110.79 Torque

Needless to say my car is either a piece of garbage, or something is SERIOUSLY wrong.

.........oh and not only was I the only rotary, but also the only car under 150HP. My FC is gonna just sit in the driveway and THINK about how bad she's been this past weekend!!

The dyno day was for an SRT-4 club, so I was NOT representing the Mazda power very well...... Nor was my FC representing ANY sort of "rotary power," either.

Seriously, though, guys... please don't tell me this is normal. She's an '87 N/A, with just a K&N Performance Kit Air Intake. That's it. New spark plugs and wires this past October... nothing else... except 89 octane fuel and oil changes periodically.

They did the air/fuel ratio, but it's not on my charts... and the guy said that it was because she was running so lean... yet I think there isn't any reading on my chart cuz he forgot to put the reading on there.

Please suggest a list of troubleshooting tips, because I'm pretty pissed at my rotary at the moment. I know ONE solution is to drop a 350 in the FC.......... LOL.

Last edited by PerkyStina; 06-13-05 at 01:04 PM.
Old 06-13-05 | 01:05 PM
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And you know your 6th ports are working properly? They could very easily be the cause of your problems if they're not opening.

Slightly clogged cats/mufflers?

-=Russ=-
Old 06-13-05 | 01:11 PM
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well the 89 octane will lower your HP right there, but the numbers are not far offline of what they should be, and if the K&N filter is not in a cold air box, but rather the lame *** K&N FTPK kit, that would drop your HP another 5 or 6 HP also.

A S4 non turbo with no mods and decent compression will normally put rear wheel HP around 112-120 HP.
Old 06-13-05 | 01:15 PM
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yeah I have seen some low dynos for NA's and stockish t2 before and the onners are stunned because when they are asked to guess the numbers they consider what stock should be and add with mods. But most people have a low compression engine due to age and mileage they don't consider. I say check compression and that will tell you why you are missing 20hp
Old 06-13-05 | 01:19 PM
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Here's the dyno sheet...
Attached Thumbnails Major HP loss!  Avg 104 HP!-dynosheet6-12-05small.jpg  
Old 06-13-05 | 01:22 PM
  #6  
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From: Rohnert Park CA
Originally Posted by Bukwild
I say check compression and that will tell you why you are missing 20hp
remember, brand new the motors only put out 146 (or so) at the flywheel.

Toss in the 20-25 HP loss on through the drive train (15 or so%)

and you are down to around 120 in perfect condition
Old 06-13-05 | 01:37 PM
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Ugh. That makes me mad! I refuse to drive another N/A rotary again! This one is IT.

That is SO embarrassing! I DEFINITELY drive a chick car. Ugh.
Old 06-13-05 | 02:03 PM
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I was wondering why you would drive so far to dyno a stock N/A anyways...
Old 06-13-05 | 02:07 PM
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Power is not everything in my opinion. I was a bit shocked back in the day when I dyno'd my stock turbo II. Then came along driving the twisties, and that bad feeling went away. I was again shocked (In a good way) about how well the car drove through the twisites around here. Some friends of mine and myself do some spirited driving from time to time and they are always pissed that my low hp car is able to keep up if not pass them. These cars are not made to pump out massive amounts of HP. They can with proper modifications, but not nearly in stock form.

Anyone saying an FC is a girl car based on HP has got other issues. Who cares what they think anyways? Honestly if your pissed off that much about the power, expecting more or wanting so much more power...Maybe the FC is not the best choice for you. Even Turbo II's are not that much more powerful. You will still need lots of mods to pump up that hp safely.

Just like mark said, the drivetrain sucks up some of the hp. I agree as well those numbers are not that far off from what they should be.

Just my thoughts really....

Last edited by elfking; 06-13-05 at 02:12 PM.
Old 06-13-05 | 02:13 PM
  #10  
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Buy the header and cat replacement.
http://www.racingbeat.com/FRmazda2.htm

You should make 160 hp plus...
Old 06-13-05 | 02:18 PM
  #11  
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Originally Posted by perkystina
Ugh. That makes me mad! I refuse to drive another N/A rotary again! This one is IT.

That is SO embarrassing! I DEFINITELY drive a chick car. Ugh.
A chick car has nothing to do with HP (of course that you have actually lowered the HP due to your mods is another whole issue).

And the fact that you are basing how much manhood you have on your car's HP output says that you need to re-evaluate at lot of things in your life.

Didn't you like your car- were you not proud of you car when you first got it... didn't you say to your friends," look what I got!" with a gleam in your eye??? Nothing has changed in the car.

But some simple dyno run makes you want to dump the car and call it a chick car... I guess you don't get what the RX-7 is about.

Last edited by Icemark; 06-13-05 at 02:21 PM.
Old 06-13-05 | 02:24 PM
  #12  
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Does it feel slow when you drive it? I had issues with my oil metering pump and the air flow meter that both took away horsepower, but it was pretty noticeable.
Old 06-13-05 | 02:26 PM
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Originally Posted by Icemark
A chick car has nothing to do with HP (of course that you have actually lowered the HP due to your mods is another whole issue).

And the fact that you are basing how much manhood you have on your car's HP output says that you need to re-evaluate at lot of things in your life.

Didn't you like your car- were you not proud of you car when you first got it... didn't you say to your friends," look what I got!" with a gleam in your eye??? Nothing has changed in the car.

But some simple dyno run makes you want to dump the car and call it a chick car... I guess you don't get what the RX-7 is about.
I'm a girl, dude. LOL

And no... it's definitely weak... compared to the better models out there. Mine in particular is now labeled a chick car... yet she's NOT going to stay that way. She needs help. The minor details... including the lower octane fuel and the K&N will help a little... but I'm still pretty disappointed.

Last edited by PerkyStina; 06-13-05 at 02:29 PM.
Old 06-13-05 | 02:31 PM
  #14  
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From: Rohnert Park CA
Originally Posted by perkystina
I'm a girl, dude. LOL
... hmm okay, then you judge your car's manhood on HP... well again you need to re-evaluate.

The minor details... including the lower octane fuel and the K&N will help a little... but I'm still pretty disappointed.
Probably 10 HP just between those two, which puts you back into stock range
Old 06-13-05 | 02:42 PM
  #15  
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Stock range is ok... the crap I got SUCKS. Stock range IS embarrassing, too, but at least it's not pinned on only my car. (Pride issue) I used to be really proud of my rotary... because of the way it works, and the power it produces. After this weekend, all I gotta say is, "what power?"

Turbo-charged is the only way I plan to go!

...Not with this one, though. She's gonna stay my daily. I think I want a Turbo II... for now.
Old 06-13-05 | 02:45 PM
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Originally Posted by perkystina
Ugh. That makes me mad! I refuse to drive another N/A rotary again! This one is IT.

That is SO embarrassing! I DEFINITELY drive a chick car. Ugh.
Well depending on what kinda power your after an N/A can still be right, but it you want 210 + WHP w/o doing some big porting and sinking alot of money into an N/A just to hit that then you might wanna go turbo. Just remember more things can go wrong and 94 octane isn't cheap, at least not where i live , just found that out yesterday!!!

there have been ppl that have posted 200+ Dyno sheets on an N/A but it probably wasn't by any means easy


If you'll be happy with 160WHP then a good intake full unrestricted exhaust and and probably an SAFC as well as lowest octane you can find. Might need to do a few more things but 150 - 160 is probably something you can attain on a good engine w/o any porting.
Old 06-13-05 | 05:47 PM
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Originally Posted by Bukwild
...I say check compression...
I second that motion...
Old 06-13-05 | 06:11 PM
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its not a "chick car"
if it has 50/50 weight distribution, RWD ,2 seater, and was one of the best cars to come out in the 80s and still hangs with cars of today.

its a japanese sports car its not ment to be a straight line muscle car, its designed to be able to go fast threw a road course with twisty turns!

with a fuel exhaust RB header and everything. my 87 na dynoed 133 HP to the wheels,which with less weight in a na, is really close to stock turbo II power levels.
l


ol.... tho i will admit i got the itch for more power and sold 1 of my NA for a turbo II but... the na was a really fun car too!

Last edited by KompressorLOgic; 06-13-05 at 06:14 PM.
Old 06-13-05 | 06:43 PM
  #19  
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Damn back when my s4 only had full exhaust and intake (and a couple misc things) I hit ~120 on the dyno with forced closed aux ports! One of them was actually about 1/2 the way open, the other was fully shut.

Makes me wonder what I was really putting down and what I am right now, hmmm.
Old 06-13-05 | 06:51 PM
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keep in mind..... not all dynos put out accurate #'s....you could go to five different dyno's and come home w/ five different hp ratings......whos to say that the dyno isnt off a little??? i know of at least 2 dnyos that put out low hp #'s!! one of them is vishnu performance...their dyno is really off!

note...im not saying that the dyno IS off...im just saying its a possibility!! if it is off, its probubly only a few hp's off! the higher the hp, the harder it is to get an accurate rating

Last edited by vipers; 06-13-05 at 06:54 PM.
Old 06-13-05 | 06:52 PM
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OK.
S4 NA's are SLOW.
Both my 88 FC's ran 17's.

Now onto your car.
The NA's are designed to run on 87 octane. Anything higher and the burn rate will be off and it won't make it's designed HP. The only time you want to run higher octane is if your forced induction and at that point your using it as a detonation barrier.

The Filter will not improve anything unless you have it seperated from the engine bay.
The stock filter system sucks air from an external source. A aftermarket filter will suck HOT engine bay air. The engine bay heat will decrease the HP.

Compression like said above can also affect your cars HP output. The 150hp numbers were back when they had perfect 120psi compression and even then it was at the flywheel.



So.....
Just curious. What numbers were the Srt-4's running?
I've always wondered if I had a chance against the ones around my town.
Old 06-13-05 | 07:08 PM
  #22  
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Originally Posted by Icemark
And the fact that you are basing how much manhood you have on your car's HP output says that you need to re-evaluate at lot of things in your life.
HEHEhehehehe SHE's a chick=no manhood at all.
Old 06-13-05 | 07:35 PM
  #23  
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i think its one of the first N/A's ive seen putting more torque than HP. i'd be somewhat happy with those results with that car.
Old 06-13-05 | 07:49 PM
  #24  
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Originally Posted by Digi7ech
OK.
S4 NA's are SLOW.
Both my 88 FC's ran 17's.

Now onto your car.
The NA's are designed to run on 87 octane. Anything higher and the burn rate will be off and it won't make it's designed HP. The only time you want to run higher octane is if your forced induction and at that point your using it as a detonation barrier.

The Filter will not improve anything unless you have it seperated from the engine bay.
The stock filter system sucks air from an external source. A aftermarket filter will suck HOT engine bay air. The engine bay heat will decrease the HP.

Compression like said above can also affect your cars HP output. The 150hp numbers were back when they had perfect 120psi compression and even then it was at the flywheel.



So.....
Just curious. What numbers were the Srt-4's running?
I've always wondered if I had a chance against the ones around my town.
Not all n/a s4's are slow, not at all.

And remember the s5 n/a's are rated at the SAME 1/4 mile time as the s4's, they may have a bit more power but they are also heavier.
Old 06-15-05 | 01:23 AM
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Hey, perkystina...

I put a low(er) mile s4 N/A motor into my '88 N/A and was decently happy with how it was performing until I got pulled on by an 8v MkII GTI...

Needless to say, I did a couple tests and found out that my 5th and 6th ports weren't functioning, so I wired them open to see if I noticed a difference...

I did. The top end came alive! (relatively speaking) After gutting my cats with a drop in filter and a good clutch, I was able to beat cars in my N/A that my (tired) TII lost to!
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