Steve,

So if someone wanted more low end power would you advise adjusting the cam timing (presumably with a cam gear or some sort of adding block???) to accomplish that?

what are the downsides of such a device...

Cheers,
Boris

 

Boris, You mentioned stock intake yielded the highest results, did you have the air filter when you ran it?

Steve Weiner, Where should I set my OBD II scanner to monitor the knock sensors?

Thank you much guys ~Mike

 

For the guys who got 240~250HP, was the temp during less than 68F and did you have Sunoco 93 fuel or equivalent?
Thanks again~Mike

 

Boris,

Do you know how much difference the RS pulley made on its own?

 

I was using 93 octane from the local "Quik Trip". Ambient temperature was around 70 degrees.

Chip

 

Thanks Chip. I think that if intake air temp is above 68F the ECU starts cutting back the power. I remember the temp when I did my Dyno, temp was 77.34 F A friend also mentioned to use Sunoco 93 fuel. He also said that If I do the 2nd and 3rd pull I should get higher readings. This is because the gear oil will offer less resistance once it heats up. However, all that is doing is reducing the drivetrain loss, it is not making more power. In other words you might lose 20% on a cold trans, and "only" 15% on a warm one.

 

Mike, thats interesting about the ECU cutting back on power above 68 degrees. I wonder what it does, retard timing some increments? And why would it do that pre-emptively, in the absence of evidence of pinging from the knock sensors?

I can undrestand less power being developed as intake temperature rises, since air density is lower, but it doesn't sound like that is what Joel Reiser was talking about.

Chip

 

Don't forget you have to run the gearbox awhile to heat up the gear oil. You can warm up the motor, but that does not do much to warm up the gear oil. It is typical to pick up some power on the 2nd or 3rd pull because you don't get the gear oil really up to temperature until you do a first pull. The thicker it is, the more resistance, resistance is loss, which will be included in your power reading. This is one reason why some people like the engine guys at Porsche Motorsports use an engine dyno, not a chassis dyno -- they are not interested in dynoing the CV joints and the transmission for losses, that is a separate science project.

 

I would think that increased parasitic drag from a cold tranny would show everywhere on the curve - i.e. it wouldn't just flatten out the top abruptly >5000 rpm. I think if anything, it's probably heat causing timing to cut back. Do you still have the underpan on your car?

Brad

 

Brad, I removed the underpan long time ago. I highly think that the flatening on the top was 'caused by the tech/driver because I told him not to red line the engine and he probably got over cautious.

 

Oh right! Forgot you mentioned that a while back, must've had one too many pints last nite BTW love those Carrera lightweight wheels!

 

The one I spoke of made MORE power on the second pull, not the first. It is typical to make more power as the gear oil warms up and flows better. You're right the loss while cold, or the gain when warm, will be spread across the powerband. I don't know who said >5000 rpm.

 

JMreiser,

Did you say that if just one circuit (1 out of 12) plug is not firing, it will not give me a CEL or misfire code?

I didn't do the dyno today 'cause the shop tech are still at the race track.

Thanks much
~Mike

 

Don't dyno the car if you do not have all 12 plugs firing!! Limping around on the street is one thing, but if you put the engine to full load it will seriously hurt itself that way. Like that famous 50 year old radio blooper, 45 people were killed in a train wreck today, 12 of them seriously.

With OBD-II you "should" get a code, I think it would be Misfire on Cylinder #X, but you don't want to find out the hard way. Murphy's law says that since most people get a Check engine light when they don't want one, you might not get one when you need one.

It should be running smoothly, perfectly, before you go on the dyno.

Why do you suspect one plug or wire is bad?

 

Hi jmreiser, No I don't suspect a dead circuit. I was just reading your previous email, and you mentioned to hook up on the PST II(If low power/HP in the dyno is persistent) and turn 1 circuit at a time to see if the engine start idling rough. I do have OBD II(97 Carrera), so If I have a circuit now working, I should get a CEL right?

On another note, Just to make sure, I also checked my dual distributor this afternoon to make sure that both rotors are turning. I removed the caps and crank the engine to see if they're both turning. Which they are. What's your take in replacing that belt, wait for 50K or so, or replace it with in so many years(car is now 7 years).


as always, thank you ~Mike