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Shut off motor between runs and spray or let idle and spray? Which will make more HP?

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Old 08-03-2005, 10:02 PM
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Originally Posted by TeamRX8
that's why you have to retune the jets and set the bowl fuel level height just right
And this is important because you need maximum carbonation because the extra air bubbles help cool your engine from the inside AND help make more power because it gets more air into the engine too.
Old 08-04-2005, 10:44 AM
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Originally Posted by ULLLOSE
Cooler cars run richer.... A hot motor will lean out.
Why? Looking to learn something here.
Old 08-04-2005, 02:07 PM
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good luck ...
Old 08-05-2005, 01:39 AM
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I recall reading a thread about the Racing Beat open house where they were showing their engine test bench. They could maniupulate the various ECU inputs to see the effect on the engine. IIRC, coolant temperature had a significant effect on engine output.
Old 08-05-2005, 05:40 PM
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Fastmike,

I'm sorry but I don't remember the details. I tried to search to find the thread but didn't find it. In short, RB was able to turn a dial and simulate different coolant temps to the ECU. After a certain temperature, the ECU changed either the fuel map or timing (that's the detail I don't remember. ).

I would suggest that you ask the question to Racing Beat. Jim Langer was the one demo-ing the test bench (IIRC). RotaryGod and some other forum regulars were in attendance. Seach for "Racing Beat focus group" for a discussioin of the session.
Old 08-27-2005, 05:53 PM
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What were your numbers?
Old 08-27-2005, 07:02 PM
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Thumbs up so end product. Drive first : Now what about numbers

Ok FastMike, lets hear the numbers on the HP and TORQ measurements when in 1st , and 2nd. and any other numbers for any other gears.

Thanks

Bring that 8 over to the the Tricities next week end
Old 08-27-2005, 11:32 PM
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I'm not sure if I'm going to the PCA event on Saturday, but I think Ron and Annie might be PCA members...
Old 08-28-2005, 09:13 AM
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Here's what I do when I run my RX-7 (autox or 1/4 mile)

open the hood and let it idle with AC on (to turn on the fans) for a few minutes

shut it off but let keep the fans running

when moving in the staging lanes I start it, move it and shut it off again, this circulates the cooled coolant throught the engine but doesn't give it time to heat it up again
Old 08-28-2005, 10:58 AM
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Originally Posted by fastmike
You only dyno is 5th gear.
We were hoping to bring the car to Bremerton next weekend but maybe not now...

Today's best hp peak at 177 and best TQ at 134.(run2 of the day)
Down from there....worst(taking out the first cold pull) was 170/129.
Most were low 170's and low 130's.

Last test of her car(same dyno)with ghetto straight pipe and stock exhaust on 2/26/05 got a repeatable mid 180's and mid 130's on TQ. Straight pipe getting much more overrev compared to stock exhaust that day and more peak hp. Stock just starts dropping hp/tq severely at 8500 rpms. Doesn't even make it to the 9100 rpm rev limiter on any of the 3 runs with stock exhaust. Dyno must stop recording when it sees such a drastic downward line or when it gets below 50 ftllbs or something.

We are going to go back to a true straight pipe and see if her cats are plugging? One car during the 2/26/05 test had melted/plugged cats and he couldn't get over 130 hp even though the car still sounded ok.
Maybe the muffler we went with is causing some restriction??
We should be able to replicate the earlier tests???

Maybe we will get the straight pipe on early this week and do a quickie dyno one afternoon. If we can find our "lost" hp, we will bring the 8 to Bremerton..

SURE WOULD BE NICE IF SOMEONE WOULD INVITE US TO THE PCA EVENT ON SATURDAY! LOL!
Hmmm...who could do that?


FM
So what was the temp back in Feb when you did your first dyno runs? What was the temp on your most recent runs. Air temp will have some effect on power output. Also did you have the same wheels and tires on the car both times?
Old 08-28-2005, 09:21 PM
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Old 08-29-2005, 06:34 AM
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Originally Posted by neit_jnf

open the hood and let it idle with AC on (to turn on the fans) for a few minutes
I'm confused, everyone keeps talking about leaving the AC on. Do you just mean the vent fans?

When I'm done with a run, AC is OFF, but I turn the fans on full blast and heat all the way up. Can't sit in the car between runs though. :D

I used to idle the car for 30 sec or a minute before turning off the engine and leaving the fans going. But then I had a scary moment when the 8 didn't want to start bewteen runs (need that battery TSB). Since I'm not super competitive (yet) I figure I'm in it for fun, leave it idling.
Old 08-29-2005, 11:54 AM
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Originally Posted by pcimino
I'm confused, everyone keeps talking about leaving the AC on. Do you just mean the vent fans?

When I'm done with a run, AC is OFF, but I turn the fans on full blast and heat all the way up. Can't sit in the car between runs though. :D

I used to idle the car for 30 sec or a minute before turning off the engine and leaving the fans going. But then I had a scary moment when the 8 didn't want to start bewteen runs (need that battery TSB). Since I'm not super competitive (yet) I figure I'm in it for fun, leave it idling.
If you leave the AC on with the car off the compressor doesn't run but it forces the electric fan to run.

JV
Old 08-29-2005, 07:47 PM
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Right. I just don't understand why everyone keeps saying the AC. You can always turn the AC off. While it is dependent on the fan being on, the fan is not dependent on it.
Old 08-30-2005, 05:19 AM
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I don't know how to get the cooling fan to run without hitting the A/C button. You do know we're talking about the radiator fan, not the interior ventilation fan, right?
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