850 r ecu in t5?

**Bigsi15** · Sunday 7th February 2016, 21:41

Quick one guys, can an 850r ecu be put directly into a t5 for a slight performance increase?

Thanks in advance!

**nottsgreent5** · Sunday 7th February 2016, 21:48

Yip should be a straight swap bud

**Bigsi15** · Sunday 7th February 2016, 21:53

Ah cool and would it give the r performance too? Thanks for your reply

**Bigsi15** · Sunday 7th February 2016, 21:53

Also would it matter if it was from an auto car going into a manual?

**Shinsplintz 101** · Monday 8th February 2016, 10:53

Putting a standard 850R mapped ECU [AUTO] into a T5 should theoretically give you a 15hp gain - 240bhp in a R Auto - they both ran the same turbo [15g] - you might want to put a set of white injectors in to be safe.

Putting an auto ECU in to manual will be fine - but you may find flat spots in the power delivery. You cant do it the other way around, manual into an auto that is.

All the best, Morgan

**Saaamon** · Monday 8th February 2016, 12:48

Manual ECUs hold on to the revs unlike autos.

**MoleT-5R** · Monday 8th February 2016, 12:58

If your thinking of buying an 850r ecu to go in your t-5, I would recommend trying it first before handing over your hard earned cash as sometimes some 850r/t-5r ecu's will not start some t-5's, If you've already got one you may be lucky and it may work for you, I have an 850r ecu here that doesn't like working in our gul t-5r but will work fine in the later olive t-5r, this could be due to obd1/2 differences and as mentioned above an auto ecu will work fine in a manual car but not the other way around

**claymore** · Monday 8th February 2016, 14:08

As Aid says, if your car is a has the obd11 port under the coin holder, it will work, if you have the diagnostic port in front of the ecu under the bonnet, it won't work.

**Shinsplintz 101** · Monday 8th February 2016, 14:11

Plus 1 to the above. I have a hlm/Rica 304 in mine that will run on every car I've tried in, however I also have a similar ECU that won't. Funny old business swapping about ECU - thinks it something to do wit the immobiliser.

**Bigsi15** · Tuesday 9th February 2016, 20:34

Thanks for the replies guys. I have (I assume) an obd 2 port below the radio in a 96 model year car so guess will have to see, got one cheap so worth a shot I guess. Il keep you posted

**don kalmar union** · Tuesday 9th February 2016, 22:09

If my memory serves me well the 850R was the first Volvo to run the Motronic 4.4 rather than the 4.3 in the earlier cars, they have different internal voltages and cannot be swapped.

But like for like if you have bought a spare ECU for the earlier cars if you put it in your car and it runs it, however roughly, you can flash it with the calibrations that you need, either standard or aftermarket. So certainly try before you buy.

Don.

**MoleT-5R** · Tuesday 9th February 2016, 23:49

Originally Posted by Bigsi15

Thanks for the replies guys. I have (I assume) an obd 2 port below the radio in a 96 model year car so guess will have to see, got one cheap so worth a shot I guess. Il keep you posted

and does it run???, being obd11 you stand a better chance, but it's not guaranteed.....good luck and keep us posted, it would also be handy to know the ecu no. for further reference

**Bigsi15** · Thursday 11th February 2016, 17:43

Ok update. Unplugged battery, put in new ecu, connected battery and started fine. All other equipment works fine. Only thing I am getting is periods of uncontrolled boost. I believe stock is around 12 psi but I'm getting spikes up to 1 bar then drops back a bit. Seems to do this from about 3k rpm onwards. Goes really quickly too. The ecu was once tuned but this was reset as per my request to stock r and I see no reason to not believe he did it. Ran fine on t5 ecu although occasionally a bit low on boost. Will have a fiddle tomorrow to check vac lines which are pretty new and loosen wastegate a bit as I think I gave it a turn or so before. Any other ideas?

Thanks guys

**martin_r_smith** · Thursday 11th February 2016, 19:05

Wasn't the extra horses the R had gained by allowing an overboost to occur? Could be me talking bullocks though.

**claymore** · Thursday 11th February 2016, 19:17

Originally Posted by martin_r_smith

Wasn't the extra horses the R had gained by allowing an overboost to occur? Could be me talking bullocks though.

that was the T-5R

**MoleT-5R** · Thursday 11th February 2016, 19:56

could the bcs be on it's last legs...just a thought

**Bigsi15** · Thursday 11th February 2016, 20:24

Yes I was thinking that possibly too. Or wastegate, seems to restrict the boost at wot but only up to about 2.5-3k rpm then peaks. Seems to be worsening too, earlier it would spike slowly then settle around 0.9-1 bar

**MoleT-5R** · Thursday 11th February 2016, 20:34

Originally Posted by Bigsi15

Yes I was thinking that possibly too. Or wastegate, seems to restrict the boost at wot but only up to about 2.5-3k rpm then peaks. Seems to be worsening too, earlier it would spike slowly then settle around 0.9-1 bar

bit of wastegate creep....possible

**Bigsi15** · Thursday 11th February 2016, 20:43

Can you explain that more for me please? Iv read a bit about that but what symptoms will that give and how can I resolve it? I wonder if I have the actuator a bit tight as I turned it a turn or so on my original setup a while ago. Sorry it's probably a very easy answer!

Thanks all very much once again

**Bigsi15** · Thursday 11th February 2016, 21:03

So found this in the Garrett site, almost perfectly describes it:
A. Boost creep is a condition of rising boost levels past what the predetermined level has been set at. Boost creep is caused by a fully opened Wastegates not being able to flow enough exhaust to bypass the housing via the Wastegates itself. For example, if your boost is set to 12psi, and you go into full boost, you will see a quick rise to 12 or 13psi, but as the rpm's increase, the boost levels also increase beyond what the boost controller or stock settings were. Boost creep is typically more pronounced at higher rpm's since there is more exhaust flow present for the Wastegates to bypass. Effective methods of avoiding or eliminating boost creep include porting the internal Wastegates opening to allow more airflow out of the turbine, or to use an external Wastegates.

Mole you may have hit it on the head there. Any ideas how to solve this, can you tighten the arm too much so it limits the opening perhaps?

Thanks again