Slater Posted March 18, 2005 Report Share Posted March 18, 2005 I have a spare ECU I am playing with on my quest for hacking the Volvo ECU.Anyways, it's a 98 S70 T5 ECU. Anyways, I swapped it in my ECU and have been driving on it for a few days now. I've noticed a few things.1. The car feels as fast if not faster. This is suprising because I was expecting it to be sloooow. Now, before you say you can't feel it with the butt dyno - I am a big NA guy and believe me, you CAN definitely feel 20HP.2. The stock boost gauge isn't the best I know. But I noticed that with the S70 the needle goes to the same spot as far as I can tell and the REALLY interesting thing is that it doesn't fluctuate like the T-5R ECU. For example, with the T-5R ECU, when you mashed it in first it would go to about 80% boost (i.e. the white portion of the stock gauge), then a second later to 90% and then fall back a little back to 80% or even 75%, then back up depending on if it shifted or not like a spike between shifts. It just seems like it's fluctuating quite a bit. With the S70 ECU it goes to 90% (or 85%) and stays there the whole time. I should mention that I do NOT have any boost leaks so that is not the issue.Now, here's a few things that I think may be going on. The 98 would have had a 16T turbo, which is basically the same CFM as a 15G but I'm sure Volvo did some sort of tuning on the fuel and/or timing maps. Also, 96+ doesn't have EGR wven though my car does. There is absolutely no CEL codes from running an ECU with no EGR on a car equipped with EGR. What I do not know is if the EGR is normally CLOSED and the ECU tells it to OPEN. If that's the case that would mean that the S70 ECU may feel more powerful because it doesn't have the hot EGR gas being reintroduced into the intake. I know automakers say EGR cools the temps in the combustion chamber which is true because there's less air to burn, but it's at the expense of HP. So screw that crap.Also, the stock needle is by far no accurate means to meausure boost. What I really need to do is hook up my Defi gauge, or do wait until I have datalogging capabilities to figure out exactly what is happening with the boost. I also need to dyno the car back to back with the different ECUs.And no, it's not a cracked 15G that is losing boost at high rpms. Remember, nothing has changed other than the ECU. The turbo is the same, everythig is the same. I'm just popping the hood and switching ECUs.The only thing I can think is causing the apparent fluctuations with the T-5R ECU is because to get the T-5R to 240HP Volvo upped the boost a tad under 2psi for 7 seconds. That means that I should see variations in the boost. What I haven't figured out is if it's time based or rpm based, or maybe load or speed based. I just know with the S70 ECU it stays rock solid, power delivery is smooth, and it feels very nice, smooth, and fast. With the T-5R ECU it still feels fast, but it just doesn't feel as nice and refined and smooth as the S70 ECU.]Has anyone else tried this or run into the same thing? Any ideas as to what the deal is? I'm tempted to just roll with the S70 ECU for a while!- Slater Link to comment Share on other sites More sharing options...
9mil Posted March 18, 2005 Report Share Posted March 18, 2005 I havent tried it, but I often thought that it should be possible for a 95 850 to go up to an S70 ECU, but the S70 wont work (at least not without dumby lights) in the 850...if I am picking up what you are putting down.9 Link to comment Share on other sites More sharing options...
T5BRICK Posted March 18, 2005 Report Share Posted March 18, 2005 Slater, i've also got a '96 855. mine is just a Turbo though.as far as i know, the only real difference between the engine in your car and mine is the ECU, correct?so i should be able to pick up a T5R, 850R or even a S70 T5 ECU and get a "free" 20HP? Link to comment Share on other sites More sharing options...
550 Posted March 18, 2005 Report Share Posted March 18, 2005 Maybe. It is a tough area(gray area if you will) Not all cars will react the same. Obviously. My guess is slater is right about the 16t mapping, I would imagine it has to be a little bit different (at least). So it could work but does garauntee the gains.Although I would be interested to see how the s70t5 ecu would act on my car being that I have the LPT engine. I do plan on getting the 16t over the summer but I would definetly be going custom mapping. Link to comment Share on other sites More sharing options...
Slater Posted March 19, 2005 Author Report Share Posted March 19, 2005 I havent tried it, but I often thought that it should be possible for a 95 850 to go up to an S70 ECU, but the S70 wont work (at least not without dumby lights) in the 850...if I am picking up what you are putting down.9←I currently have a 98 S70 T5 ECU installed on my 95 T-5R with NO CELs.If you do it the other way around you WILL get lights because the 95 ECU controls the EGR system which is not there on a 98. But a 98 doesn't even know what EGR is so when you put it in a 95 car with an EGR system, it just ignores it. Link to comment Share on other sites More sharing options...
JHEIII874T5M Posted March 19, 2005 Report Share Posted March 19, 2005 yea, it's fun to play with ECU's, my buddy has my 96 Speedtuning ECU in his 95, and I have his 95 stock ECU in my 96 car... the 95 ECU doesn't really have a boost cutout, it's kind of fun, rely on the 475's and walbro pump crank her to 16 psi Link to comment Share on other sites More sharing options...
JESSEXC Posted March 20, 2005 Report Share Posted March 20, 2005 I've swaped a 97 lpt Upsolute ecu into a 96 hpt and it ran fine. Link to comment Share on other sites More sharing options...
lax01 Posted March 20, 2005 Report Share Posted March 20, 2005 Slater could it be because the x70 T5 run more boost at stock than the 95 T5-R? Isn't the S70 set at 12? and the T5-R set to 10.something? Anyways, I found out yesterday that my rear O^2 sensor isn't disabled, but I'm confident that if we find the right hex key, we will be able to disable it (probably the same thing for the EGR as well on the 95s) Link to comment Share on other sites More sharing options...
BlackT5 Posted March 20, 2005 Report Share Posted March 20, 2005 I thought the Motronic 4.4 uses a faster processor. Link to comment Share on other sites More sharing options...
EOBD Posted March 20, 2005 Report Share Posted March 20, 2005 I thought the Motronic 4.4 uses a faster processor.←No, the 4.3 & 4.4 share the same circuit board. The difference is that the 4.4 has a bigger FLASH device fitted. The earlier 4.3 had a smaller FLASH memory, but a few of the later ones just prior to the change over had the larger FLASH chip. This was because the firmeware became larger due to OBD2 requirements etc. Link to comment Share on other sites More sharing options...
EOBD Posted March 20, 2005 Report Share Posted March 20, 2005 Slater,Have you thought of trying a MAP from a standard UK T5? You could drop the chip in and this way you would do away with the need for rear O2 sensor, no EGR and perhaps some gain, who knows? Link to comment Share on other sites More sharing options...
Slater Posted March 20, 2005 Author Report Share Posted March 20, 2005 Slater,Have you thought of trying a MAP from a standard UK T5? You could drop the chip in and this way you would do away with the need for rear O2 sensor, no EGR and perhaps some gain, who knows?←Shhh, you can't give away all my secrets! I have to get my new tubular manifold first! Link to comment Share on other sites More sharing options...
Slater Posted March 20, 2005 Author Report Share Posted March 20, 2005 Slater could it be because the x70 T5 run more boost at stock than the 95 T5-R? Isn't the S70 set at 12? and the T5-R set to 10.something? Anyways, I found out yesterday that my rear O^2 sensor isn't disabled, but I'm confident that if we find the right hex key, we will be able to disable it (probably the same thing for the EGR as well on the 95s)←If the S70 T5 is set to 12psi, then what is the V70R set to? Link to comment Share on other sites More sharing options...
Guest Guest Posted March 21, 2005 Report Share Posted March 21, 2005 I thought the Motronic 4.4 uses a faster processor.←i cant really say if thats tru or not, but i know of one difference: the motronic 4.3 just controls boost via PI-controller whereas the 4.4 already has PID-controller (like the audi 20V turbo engines). A PID is able to control greater gaps compared to the reference value better than PI-controller which are responsible forf the "fine" tuning of the boost. PID are nowadays standard in an dynamic turbo engine. PI controller can be found today in stationary (steady RPM and exhaust gas stream) industrial machines. (i think PID is just a german acronym) Link to comment Share on other sites More sharing options...
Guest greg from the volvospeeddoghouse Posted March 21, 2005 Report Share Posted March 21, 2005 If the S70 T5 is set to 12psi, then what is the V70R set to?←IIRC, the T5 is set 10psi and the Rs are set to 12psi. I just got a T5 and i have a R, the R is 12, I'll find out about the T5. Link to comment Share on other sites More sharing options...
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