Have I made a $1000 mistake?!?

[Blwalker105]

OK, so I am getting ready for my first base-map engine start and Turn-In Concepts is hinting that I might have made a huge error in judgment. Let's see how the Madding Crowd responds.

My donor car ECU is a 2003 WRX with a 16-bit processor. I decided to go with a IAG 2.5L short block and chamber-match my 2.0L cylinder heads to the new cylinder diameter, using old-school techniques of grinding and CC'ing each combustion chamber to within 0.75 CC's, then putting everything back together with a 1.0MM head gasket to keep things real. I have numerous high-end options, including an external Bosch fuel pump, larger FP HTA 71 turbo, larger intercooler, Denso 950 Injectors, Speed Density tune, etc. When I was actually able to talk to a real person, (Clint) at TIC, he informed me that my 16-bit processor with matching Cobb Accessport would not be up to the task of providing enough mapping to go along with all my upgrades. He was very taken aback with my cylinder-head chamber-matching efforts, saying that very few people can actually perform the required labor necessary to get the job done properly. Baloney.

Where we stand now, is that he is going to contact Corbin Johnson, who does all of their tunes, to see if he is willing to go out on a limb and try and work with me.

I have used iWire for my custom harness and Cobb AccessPort and Brian has been a true professional. I now find myself in the position of considering a blended engine harness with a 32-bit ECU to satisfy TIC, while largely paying for useless things like Drive By Wire, AVCS, etc.

My question to the group is: Has no one else ever had these issues, and what is the easiest, most cost-effective way of dealing with a 2.5L engine with a pre-2004 ECU?

[Hobby Racer]

He was very taken aback with my cylinder-head chamber-matching efforts, saying that very few people can actually perform the required labor necessary to get the job done properly. Baloney.


I'm with you. I've done a few custom port-n-polish jobs in my day and they are not hard, just need to take your time and plan properly.



My question to the group is: Has no one else ever had these issues, and what is the easiest, most cost-effective way of dealing with a 2.5L engine with a pre-2004 ECU?

I can't help you with running a 2.5L on a 16bit ecu but I do have a 32bit ecu from my 2006 WRX donor that I did not use. I have the matching key/tumbler, immobilizer, and body control module needed to make it all work. If you want it PM me for info.

[autostang]

I think you should be fine, as long as the compression is at a reasonable level. I have a 2.5L sti short block, 2L heads and a double thickness head gasket. Its all being run by a 2002 wrx wiring harness and computer. Just had it tuned last month with no issues and its been running great. I took the sharp edge off the overhang of the heads, but decided not to go further. My tuner had no issues or concerns getting everything to run and has done a number of similar engines as well as at least one other 818 here in Portland. I don't know much about tuning, so cant say if the speed density tuning would cause any issues.

[Blwalker105]

I'm with you. I've done a few custom port-n-polish jobs in my day and they are not hard, just need to take your time and plan properly.



I can't help you with running a 2.5L on a 16bit ecu but I do have a 32bit ecu from my 2006 WRX donor that I did not use. I have the matching key/tumbler, immobilizer, and body control module needed to make it all work. If you want it PM me for info.

Thank you, Hobby Racer, I may be in need of your parts.

[STiPWRD]

16-bit processor with matching Cobb Accessport would not be up to the task of providing enough mapping to go along with all my upgrades.
What's your target power level? As long as it is reasonable, I don't see any major issues really. Any chance you measured the final cylinder head volume, i.e. do you know your final compression ratio?

I'm in a very similar boat - EJ257 block with wrx 2.0L heads and running an 02 wrx ECU. I haven't ported the heads but I did polish the valve chambers, I'm running hybrid specific JE pistons with oem sti head gasket. So far I haven't heard of any tuners having an issue with this sort of setup although I haven't had mine tuned yet. I've just tweaked things myself to get the car drivable. I'm on the fence on whether to get an access port or stay open source. I know of a few remote tuners that can do a speed density open source tune. The dyno tuner in my area (MachV) indicated they would only do a speed density tune if I had an access port, they could however do a MAF open source tune.

[Ajzride]

I would head to the RomRaider forum and talk to those guys, I'm sure they can tell you exactly how to get your car running on well on a 16-bit tune. There are plenty of guys there making big power with 16 bit ECU, including speed density tunes on the old ECUs.

[q4stix]

When I researched it (out of curiosity since I have an 07), a lot of people were doing MAF scaling (maybe pressure sensor too) and then compensating accordingly. I assume it would be the same with speed density but then that would be scaling the pressure sensor instead of the MAF.

I don't think you're stuck, you just need to find someone with the right experience. May be worth looking sooner rather than later if the cost will be that high.

[NevaLift2Shift]

I'm running a hybrid as well, EJ257 short block w/ the EJ20 heads (chamber matched), the factory 03 WRX ECU. I'm a novice tuner, but I built a map for it on my Cobb Accessport and eventually switched over to RomRaider so I could run the Carberry ROM. Scaling the MAF and injectors is always necessary. I also bumped up some of the enrichments for the added displacement. The 2.5L needs more timing, at idle to run properly. The MAF does run out of "mapping", but that's the whole reason you go to speed density, anyways. I think the MAF is good for somewhere close to the 400hp mark and you either have to go with a bigger MAF tube (and rescale) or Speed Density.

I would be looking for a second opinion. You can look on the RomRaider forums and people have been run 2.5L's on the 16bit ECU for over a decade. Feel free to PM me, I'd be glad to help. Again, I'm no professional tuner, but I if I can get it running with an AP and RomRaider\Tatrix\ECUFlash, I think any reputable tuner should be able to do the same.

[Sgt.Gator]

In my build thread you'll see we just pulled the JDM EJ207 and swapped in a 2016 2.5L EJ257 STI motor, but we still have the old JDM ECU. It works fine, but we don't use a Cobb AP. And to use the EJ257 heads on that ECU we had to do some AVCS block/delete stuff.
That said, we are switching to a Link ECU now, it has so many capabilities for data logging, control, and display sync with AIM dash it is worth it.

I'll probably re-build the JDM EJ207 and sell it.

[Pearldrummer7]

I'm running a hybrid as well, EJ257 short block w/ the EJ20 heads (chamber matched), the factory 03 WRX ECU. I'm a novice tuner, but I built a map for it on my Cobb Accessport and eventually switched over to RomRaider so I could run the Carberry ROM. Scaling the MAF and injectors is always necessary. I also bumped up some of the enrichments for the added displacement. The 2.5L needs more timing, at idle to run properly. The MAF does run out of "mapping", but that's the whole reason you go to speed density, anyways. I think the MAF is good for somewhere close to the 400hp mark and you either have to go with a bigger MAF tube (and rescale) or Speed Density.

I would be looking for a second opinion. You can look on the RomRaider forums and people have been run 2.5L's on the 16bit ECU for over a decade. Feel free to PM me, I'd be glad to help. Again, I'm no professional tuner, but I if I can get it running with an AP and RomRaider\Tatrix\ECUFlash, I think any reputable tuner should be able to do the same.


Similarly, I'm running a hybrid on a 2002 16 bit ECU (though someday I'd like to upgrade that). I have a built hybrid motor, and am rocking an open source tune from a tuner I knew when I lived in NY (Moon Performance).

I'm nowhere near an expert, but the general feedback I hear is that with some assumptions and slightly less smooth tuning/logging than a 32 bit you can get away with it. Finding someone experience in that might be your best bet.

[Dave 53]

I've got a 2.0 / 2.5 hybrid with upgraded injectors, turbo, etc. Still on break-in tune, go kart mode, no SB100 yet, but it was all pro built and tuned with Cobb AP. No mention of overloading the ECU.

[Mitch Wright]

Don't know enough to to add an intelligent opinion but Corbin did the tune on my car and he knows his stuff.
My car is/was a 04 2L with a JDM twin scroll and header, Cobb AP and boost controller and 1000cc injectors.

[Blwalker105]

Thanks everyone. I did cc the heads. I got close to the 2.5L volume, ran out of courage and made up the difference with slightly thicker head gaskets.

I hope to have some more info soon.

[Blwalker105]

Ok, so it’s now official: according to Clint at Turn In Concepts, they and ostensibly Corbin Johnson who is their in-house tuner, are no longer willing to tune Subaru hybrid engines whose owners have customized their cylinder heads. They feel that “the probability of anyone capable of chamber-matching their cylinder heads properly” is remote enough to not warrant their time, effort and good name to be worth their hassle. Regardless of the fact that this builder, me, custom-built a 550 cu in, Continental IO-550 $55,000 aircraft engine, then flew it and maintained it for 6 years with zero problems.

Apparently, business is very good at TIC.

[Ajzride]

What is your location?

[Hobby Racer]

Plenty of Subaru tuners out there, time to move on.

[Blwalker105]

Indeed, it is time to move on.

I’m in Indianapolis.

[Ajzride]

Scott McAfoos, Granger, IN
Open Source, Exclusively tune Subaru’s. I make regular trips to Indianapolis, Lafayette, and Grand Rapids for tuning. Feel free to look me up on local forums for these events (indianaimpreza.com, misubie.com) Contact: foos58@msn.com

[sread]

Indeed, it is time to move on.

I’m in Indianapolis.

or time to learn a new skill...isn't hot rodding fun?

[Mechie3]

Scott tuned my 06 WRX back in about 2010. I'm not a fan of street tuning, but he did a good job.