Died in flight, now no start
06-25-24, 12:52 AM
#26
Another guy on another thread was trying to read his compression with both lower and upper plugs out. That's not your issue I assume.
I am trying to imagine how your motor was running with such low compression, right up until it collapsed.
I wonder what the record for lowest compression on a running car is.
We had a car with very similar results, but the odometer was not working. We found registration records that it had at least 150,000 miles on it when it was first registered in Canada about 10 years ago.
I am trying to imagine how your motor was running with such low compression, right up until it collapsed.
I wonder what the record for lowest compression on a running car is.
We had a car with very similar results, but the odometer was not working. We found registration records that it had at least 150,000 miles on it when it was first registered in Canada about 10 years ago.
Last edited by Redbul; 06-25-24 at 12:55 AM.
06-25-24, 05:45 AM
#27
Eats, Sleeps, Dreams Rotary
I am curious whether the difference in octane ratings and/or fuel quality is giving people with JDM FDs in the US issues?
Japanese high octane is nominally 96+ RON, versus 91-92 in the US. Though I seem to remember reading that the ratings aren't 1:1.
I suppose the stock ECU should be conservative enough that it doesn't make a difference.
I'd hate to go WOT on a modified JDM car (especially with an older ECU like a PFC) with a tank full of year-old 91 octane.
Given how FDs are driven these days, that's not a very unlikely scenario.
****, I should probably drain my fuel tank before my next track day...
Japanese high octane is nominally 96+ RON, versus 91-92 in the US. Though I seem to remember reading that the ratings aren't 1:1.
I suppose the stock ECU should be conservative enough that it doesn't make a difference.
I'd hate to go WOT on a modified JDM car (especially with an older ECU like a PFC) with a tank full of year-old 91 octane.
Given how FDs are driven these days, that's not a very unlikely scenario.
****, I should probably drain my fuel tank before my next track day...
06-25-24, 08:10 AM
#28
Junior Member
Thread Starter
Sorry to hear it, but there's no way to guarantee this was caused by the previous owners or would have been caught in a prepurchase inspection. The fuel systems on these cars didn't have much headroom, and the ECU control strategy won't handle overboost situations well, and the engine itself doesn't tolerate overheating or running lean very well. IMHO, the best way to move forward is to avoid scope creep and don't try to add a ton of modifications to complicate the process of getting the car running. I would add a wideband gauge, coolant temperature gauge, replace the OMP lines, coolant lines, fuel lines and radiator, but aside from that I would try to keep it simple and get back to a fun stock-ish RX7 baseline again.
06-25-24, 08:15 AM
#29
Junior Member
Thread Starter
Another guy on another thread was trying to read his compression with both lower and upper plugs out. That's not your issue I assume.
I am trying to imagine how your motor was running with such low compression, right up until it collapsed.
I wonder what the record for lowest compression on a running car is.
We had a car with very similar results, but the odometer was not working. We found registration records that it had at least 150,000 miles on it when it was first registered in Canada about 10 years ago.
I am trying to imagine how your motor was running with such low compression, right up until it collapsed.
I wonder what the record for lowest compression on a running car is.
We had a car with very similar results, but the odometer was not working. We found registration records that it had at least 150,000 miles on it when it was first registered in Canada about 10 years ago.
I think it was low on compression and I just drove the nail in the coffin. I think there is a lot that i ignored, that I'll have to pay for. It's easy to get excited and overlook things. I'll definitely take ownership on that.
06-25-24, 08:21 AM
#30
Junior Member
Thread Starter
I am curious whether the difference in octane ratings and/or fuel quality is giving people with JDM FDs in the US issues?
Japanese high octane is nominally 96+ RON, versus 91-92 in the US. Though I seem to remember reading that the ratings aren't 1:1.
I suppose the stock ECU should be conservative enough that it doesn't make a difference.
I'd hate to go WOT on a modified JDM car (especially with an older ECU like a PFC) with a tank full of year-old 91 octane.
Given how FDs are driven these days, that's not a very unlikely scenario.
****, I should probably drain my fuel tank before my next track day...
Japanese high octane is nominally 96+ RON, versus 91-92 in the US. Though I seem to remember reading that the ratings aren't 1:1.
I suppose the stock ECU should be conservative enough that it doesn't make a difference.
I'd hate to go WOT on a modified JDM car (especially with an older ECU like a PFC) with a tank full of year-old 91 octane.
Given how FDs are driven these days, that's not a very unlikely scenario.
****, I should probably drain my fuel tank before my next track day...
I spent some time on the phone with Turblown, as eventually I'd like to go smallish single. He told me that I need to run e85 in my area or don't drive the car in the summer. Our ambient temps are 110+ consistently. He said it's the only way to keep my charge temps down. This was also told to me by a former mazda driver and rotary mechanic in my area. When I was driving it, it was around 7pm, but ambient temps were still 90+ degrees.
06-25-24, 08:06 PM
#31
There are a lot of FD in Texas. They have learned how to live with high temps, I suppose.
The very low compression readings on the one side are likely similar to what was present on the blown side.
The motor would like have gone at any moment anywhere.
The very low compression readings on the one side are likely similar to what was present on the blown side.
The motor would like have gone at any moment anywhere.
06-25-24, 10:36 PM
#32
Junior Member
Thread Starter
The very low compression readings on the one side are likely similar to what was present on the blown side.
The motor would like have gone at any moment anywhere.[/QUOTE]
That's kind of what I was thinking. No crying over spilt milk though. The build will just start earlier than I had planned.
I talked to a few locals who have said a v mount and vented hood has kept their temps in order. I'll likely just avoid driving it in the peak sun, it's hard on any car here!
I appreciate all the help throughout the thread!
06-25-24, 10:56 PM
#33
Heat may have aggravated some other problems, but I used to do canyon runs and autocross my mostly-stock RX7 in 90-100 degrees weather when I lived in southern California and it survived that. Aftermarket downpipe but stock intercooler, stock cat and muffler, even a stock radiator for the first couple of years I had it. This was about 15 years ago, so the car was probably in better shape than most RX7's being driven today. What hurt my car's original engine was driving it very hard before it was warmed up when I was in a hurry to get somewhere, the coolant seals failed and it began overheating pretty soon after that.
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