Well, today I finally got the re-tune at UMS. We made 345 WHP and 309 ft-lbs of torque, all at 93% of injector capacity and 16 lbs of boost. We could have made a bit more HP at 18 lbs of boost, but I wanted the extra margin of safety, so we backed off the timing a little, which dropped the boost. To correct my first post, I have a 4" intake (not 5"), and the car is featured as the August car in the calendar (not July, sorry). With the results today, I'm not sure what I have for a fuel system. The horse power and fuel don't match a totally stock FD. I did put a new JDM engine in the car (out of Canada). Are the injectors any different on JDM FD's? If not, perhaps the original owner put larger injectors in the car. I haven't removed them to check it out.

 

I hope you're enjoying the car man... what kind of dyno did those numbers come from? They are REALLY low seeming for a single turbo at that boost level.

Also, what is this UMS shop you keep talking about? Are they rotary specific?

 

Good Question...it was my decision to go REALLY conservative on the tune. Since I don't have to pass emissions, I'm using plenty of fuel (far from detonation) to keep the engine cooler, until I finish my intercooler plenum and heat shields. At 93% on the injectors, you can see that I could go for more, but, one step at a time. Tunes are cheaper than engines.

UMS is a local "tuner" shop here in Mesa. They also sponsor a couple of race cars. They usually have a 2-week waiting list for dyno tunes. They are not rotary exclusives, but they do alot of the RX7's around here.

I AM enjoying the car, but I have to get used to the extra power. I have harder compound "Z" rated tires, so I have to be careful, or the car will get away from you (fast).

 

If you were truly going conservative, you wouldn't be going much over 80% on those injectors, I'd wonder how much control you actually have over them above 90%, I'd also wonder what may happen in the winter when the car will require more fuel.

 

Agreed. Your stock fuel system is pretty much taxed to its limit at around 13 psi using STOCK turbo's. There is no way in hell you're running a "conservative" tune pushing a t3/t4 turbo to 18psi with the stock fuel, let's not even mention that you are playing with fire by having your "tuner" run your IDC above 85%.

I'm kinda looking forward to the "so I think I might have blown my engine" thread.

 

Agree with Fendamonky and Aeka GSR. That's pretty aggressive on "stock" injectors and fuel pump. I personally would not be going above 14 psi if it were my car set up similarly, but I'm very conservative. I'm assuming that Tony installed a GM 3 bar map sensor if he's taking the car above 16 psi? Timingwise, I would think that you're probably OK since you had it tuned during the "cooler" season here in Phx and asked Tony to back it off slightly. Summertime should only be safer. I went "overkill" on my fuel system, so my duty cycles at 16 psi are only in the low 70s. I'd suggest a future investment in larger injectors, bigger fuel pump (such as the Bosch 044), and possibly a water injection system if you TRULY want to be safe. JMO!

BTW, Tony and UMS use a DynoPak Dyno. The rear wheels come off and the dyno is attached to the rear hubs. Probably one of the more conservative dynos numberwise, so I think he would have slightly higher HP and torque numbers if doing the same tune on a Dynojet.

 

This thread went limp, I hope the OP understands the risks of his setup, I don't like seeing another fellow 7 owner with a blown engine.

 

Hey Aeka GSR. Tim here. Spoke with you for quite some time last year at Sevenstock by my CYM in the courtyard. I'm sure you remember. How's your build coming? Sorry for the momentary highjack...

 

Thanks for the concern from everyone. From what I can assertain from my own research, stock injectors are supposedly reliable up to 100%. I have talked to Carlos at CLR and Cam at Pettit at length, and they agree that the next step would be larger injectors and fuel pump, but they don't feel that I am in danger where I am. Evidently someone has done something with the stock system, or I wouldn't even be close to safe. Again, without taking the injectors out, I don't know how else to see what they are, except by careful tuning. We gradually moved up in boost and the fuel just kept coming on strong without hesitation. I ran out of air at 93% duty cycle and 17 lbs of boost. Can anyone out there give me a guess as to what size injectors I have? Are stock injectors even capable of producing what I'm getting? Tony at UMS thinks that there is a good probability that I already have larger injectors. Anyway I'm still going to see if I can find out exactly what injectors I do have. This car came to me with a Pettit "piggy-back" ecu mod and HKS intake upgrade with the stock twin turbos. Perhaps the injectors were upgraded. I don't know.

 

^^^ it is possible you may have an 850cc x 4 setup, but I've never ran that setup to really know what the limits are of it.

Oh wow, hey Tim. Your car is nothing short of amazing, the only thing that I've done was make aluminum covers for various parts of the engine bay and I'm moving over to an AEM EMS from my Power FC. Other than that I just drive it when I feel the need.