Hello,

So this car is a '94.

44K original miles. Clean carfax/title. some cosmetic damage but no accident reported. Price is considerably reasonable, asking 14k

Light mods. Guy purchased in january but switched to a different car. "I don't know much about rotaries..." he says.

Anyway here's the issue: dude has an intake, midpipe, and catback installed (not sure about downpipe). I am pretty sure it is the stock ECU which I have read is an absolute NO when it comes to breathing mods, boost creep and such.

No boost gauge installed. Owner says he barely drove it because he purchased an Evo a month after buying it. only added 900miles.

Because of its distance from me, I'd have to make a long (7+hour) trip to go see/test drive it.


I really want this car, but if **** has been compromised because of blind mods and boost creep, I will let it pass me by.

Would a compression test rule out if any problems were caused by the mods? I mean, if the numbers are dandy, is it in the clear as long as no future boost creep messes things up?

If I purchase it, I will definitely have it shipped and a cat installed, at least until I can afford a PFC.



Opinions?

Thanks!

 

Okay wait here is the short version:

Boost creep causes detonation and subsequent engine failure..if the engine is running okay, and compression is good, is it fine in this regard (as long as I upgrade the ecu before further boosting)?

or would some other internals suffer from the creep as well?

Thanks

 

It's really hard to say the condition of the engine. It could be all gummed up with carbon. It could be ready to lose a coolant seal. General rule of thumb is, be prepared to rebuild the engine no matter what the previous owner says about it.

Although in my experience, it's often the "it's only got 3000 miles on this engine, I barely drove it, it should last a long time" engines that somehow work out worse in the end.

 

Right, but if I get compression tested and numbers are good, I should have less to worry about assuming I get the boost stable?

or can boost creep negatively affect things like turbos or....other...parts (noob i am)

thanks!

 

A lot depends on how it was used.....

The stock ecu does have some countermeasures including overboost fuel cut, active timing retard and a very rich map. In my experience, with the similar bpu, I would just hit fuel cut when it was cold out and otherwise be fine. Of course, your results may vary--the point being that mods don't necessarily mean it's doomed by any means. A cat will likely cure a boost creep issue, should you encounter that. And a compession test isn't a bad place to start your evaluation.

 

If the compression test is good, there's certainly a chance it could last you a few years if you don't experience some kind of catastrophic failure like an overheat due to a coolant leak. Or it could be a really good engine to rebuild before a failure, because the housings (once cleaned up) are in good shape.

Look for even compression across all faces on both rotors rather than focusing a lot on the actual peak numbers.

 

A compression test will rule out apex, side and corner seal failure that may have occurred during overboost. It will also give you an idea of how well it was maintained. This does not mean a coolant seal retaining wall will not collapse in a month, which is actually the bigger concern with very low mileage cars that have been sitting for years, rusting on the inside of the irons.

Banzai Racing Compression Test

 

14k seems a bit high for a car with cosmetic , and questionable modding

ALSO about boost creep since you are in cali You will need a cat to pass smog , and maybe even the air pump . so if the car had those removed you MAY need to add them .

if you add a cat , even a highflow one it usually stops boost creep.


I'd do a FULL exam make sure you have good oil pressure . coolant, the coolant gauge on the OEM cluster is unreliable but you should let it warm up check for excessive smoke , and sweet smell from the exhaust .

Also check coolant levels after.

 

1) Ask if it has a current registration and if there are any unpaid fees. Unpaid fees can be verified through the DMV website. All you need is the license plate and VIN number.
2) Ask when was the last time it got smogged
3) It is the seller's responsibility to smog the car, make sure the car has been smogged very recently before any money is given
4) get compression test done


Once you have purchased the car (if it all checks out) get a boost gauge and make sure it is ACCURATE. You'd be surprised how some after market units are off
A) If the car suffers from spikes or overboost get a boost controller
B) if the car suffers from boost creep, then port the wastegate

 

Depend on color of the car and what the cosmetic damage is, and the health of the engine. 14k is on the low side for a 94 with 44k original miles.

Like everyone said, I would at least do a compression check and coolant check and go from there.

 

Anyway here's the issue: dude has an intake, midpipe, and catback installed (not sure about downpipe). I am pretty sure it is the stock ECU which I have read is an absolute NO when it comes to breathing mods, boost creep and such.

You have that backwards. A stock ECU is what has saved this car in the hands of this uninformed owner. As previously stated it cuts fuel on boost over factory 10psi and has functioning knock control.

Not to be pessimistic, but the uninformed owner is much more likely to blow the engine with a Power FC.

Unless you know how these cars should feel a compression test before buying should be considered manditory.

 

it just means the engine is good today, and since its an FD, if you assume the engine can go at anytime, you will be pleasantly surprised. if you think its got low mileage and a clean bill of health, i should be fine, the FD can go very badly.

my friends FD has some boost control problem and it overboosts on the first turbo. it overboosts so much that occasionally it throws a code 13 because the map sensor goes out of range, yet somehow the stock ecu on pump gas has been totally fine for years

factory boost cut is more like 13-14psi, although it depends on RPM

 

thanks

EVERYONE!!

I think I am going to buy this. !

Having it inspected at the nearest shop to the owner---it is not a exclusive rotary shop, but they have RX-7 experience and was recommended on the forums. All the other shops are hundreds of miles away..

Thanks everyone again!

 

Overboost fuel cut as it relates to boost creep (not boost control issues) is right around 10psi.