Single Turbo RX-7's Questions about all aspects of single turbo setups.

Unplanned road trip in my 7

Old Mar 4, 2010 | 08:53 AM
  #1  
Kansas JoyRide's Avatar
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From: Salina, Kansas
KS Unplanned road trip in my 7

As the title suggests, I am leaving because of a family emergency and have no choice but to travel in my RX7 (about 1100 mile round trip). I have one concern and am hoping for a quick reply from some of you who are running an EGT reading pre-turbo. I have a dual needle Pineapple gauge that gives an EGT temp for each rotor. The probes are mounted about I inch off of the exhaust ports.

So here is my concern. I am slowly tuning my car and have all of the needed equipment (Datalogit, computer, Excel sheets and so on). I have not yet focused on the boost cells other then to make sure I have safe timing and fuel mapped into those cells for latter when I get to that stage. I have been working slowly on the area from approximately 5 psi of boost down to idle. I currently have a fairly good idle, AFRs about where I want them, ranging from around 13.5 to 14 depending on boost and RPM range and of course, at these levels, injector duty is not an issue. So here is the deal. I am seeing EGTs that range from around 1150 at idle to around 1550 cruising at highway speed (14 afr). I know these would be considered high, but then I read Howard's post, which if I understood it correctly, states that an EGT readings off of the port like I am running are about +250-300 degree F higher than post turbo. Question is then, does that make my readings acceptable.

I forgot to mention, I am mapping my knock readings. They range from 0-1 at idle up to around 5-8 at cruise (75 mph). I have also tried backing off on timing to some very conservative numbers to see if it made a difference in the EGT readings. It did not make much difference at all.

Well I tried to give enough info to get some informed responses, I hope someone who knows is listening and will help me out. I have to leave in a few hours and want to know if I should be concerned about damaging my engine. Thanks RD
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Old Mar 4, 2010 | 09:10 AM
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Like everyone tells me, at cruise your egts will by higher, it's just the nature of things when your running lean like that. I would say pre-turbo egts are more accurate than post turbo egts just because you really don't care what the temp is like after it's had time to cool down (I would imagine) you want, as close as possible, the temps that your rotors are seeing. If you want the cruise temps to be lower your best bet is to richen up the map at cruise, of course this will drop your gas mileage but to me saving your motor from hot *** egts is more important than saving a few extra bucks at the pump. Good luck on the trip~!
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Old Mar 4, 2010 | 09:52 AM
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Has anyone ever blow their car cruising? Thinking about it, that would suck. crappy way to kill your car.

Good luck with the trip. maybe you can log it, stop for gas, upload some results.
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Old Mar 4, 2010 | 10:59 AM
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Ive blown an engine cruising. Twice. They were **** rebuilds though on atkins seals.

The first one blew in vaccum

EDIT: also, 1100 miles is nothing. Car will be fine. Your EGTs in cruise are OK, nothing out of the ordinary for pre turbo measurements @ stoich AFR's with load on it.
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Old Mar 4, 2010 | 03:04 PM
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:-O

glad I asked. Otherwise my foot would be in my mouth right now. And I am wearing socks from yesterday.
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