Can the stock ECU manage the 99 Jspec turbos?
 

Hi All:

I've looked at 2 cars recently that both claim to have the '99 JDM spec turbos.

One car is running an M2 ECU. The other is running the stock ECU. Both cars have an intake, downpipe, exhaust, etc.

Based on the research I've done, it doesn't seem like the stock ECU could support all of those bolt-ons AND the upgraded turbos?

Both cars run good and pull very hard...I'm just wondering if the stock ECU based car is running on borrowed time.

Thanks,
Sonny

how much boost were they running?

the stock ecu is tuned rich...so if they arent being obnoxious on the boost...running eleven or twelve pounds at most then you are probably ok.

the jspecs arent putting down that much more power than the stockers....

but one can run too much boost for the stock ecu on the stock twins...you see what i mean?


get a compression test on both. DO A COMPRESSION TEST ON BOTH. get the one with the best compressoin and is in the best shape.


j

At 10psi they *should* be safe. All cars are a little different, but there is plenty of fuel for all the bolt ons.. As long as the boost level is kept on 10.

If boost is in check and at the stock levels its *probably* OK. I doubt the '99 turbos flow that much more air at stock boost pressure (not warranty expressed or implied :-)

jds

You should be fine, they pretty much flow the same as healthy stock twins.

STEPHEN

J-spec twins with stock ECU
 

J-spec twins should be fine as with the stock ECU so long as you control the boost to 10 psi. The '99s are easily capable of 15-16 psi, and 370+ rwhp (obviously with the appropriate mods to the motor and fuel). The J-spec twins spool up more quickly than the stock twins, and make a bit more low-end power.

J-spec twins dyno plot
 

https://www.rx7club.com/attachment.p...postid=2807676

Goodfellas is putting down 5.1 more rwhp with BNRs

BATMAN's mechanic claims to put down 390 rwhp stock ported motor and stock twins, but I have not seen the dyno plot.

Wow, you guys rule! :beerchug: Thanks for the info!

Neither car had a boost gauge, but I was told by both owners that they were running 'stock' boost.

Sonny

If neither one had a boost gauge, then I would wonder how either owner would even *know* if they were running "stock" boost levels. ?!

My BS alarms are starting to go off here.

With intake/dp/catback(mp?) as well at the '99 turbos they would certainly be seeing boost spikes and higher than stock boost unless they took appropriate action (boost controller and/or replacement pills). And even then, they would have to have had a boost gauge on there to verify.

IMHO, the compression test is a reasonable precaution. I would recommend that you also take a mechanical boost gauge and check exactly what the boost levels are on each car (tap into the upper intake manifold with around 6-8 feet of vac hose, run the hose out the back side of the hood and into the passenger side window. Have the driver stand on it in 3rd gear and take it to around 6k RPM. Pay close attention to the boost levels at the 4500 transition.)

Good luck,

-bill

yes...ill say it again


do a compression test

I must agree. Do a compression test. DO A COMPRESSION TEST. Did someone mention the compression test already? I would do the compression test.

I would think they are just saying they are the upgraded turbos but are actually the stock turbos just to make the car worth more.

You can verify the J-spec turbo part number stamped on the turbo. I have a set on my car but don't recall the numbers.

I am having any/all potential cars checked out at Rick's Rotary in Pleasanton, CA.

Are the jspec part numbers visible while the turbos are under the car?

Thanks,
Sonny

Sonny, I'm sorry I don't recall. Try looking at the housings primary or secondary. Do a search on the parts for sale forum for j-spec twins. You'll find the part numbers there. Sorry I'm not much more help.