Control Boost with ROM Tuning?
Moderator: Matt
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
hey pete,
What size spring is in your actuator on the 2871 ? if it is set to a minimum of 8 psi and you are tuning it to say 20... I think your actuator may need a tweak as the exhaust gas will blow open the wastegate and spike your boost... you might be able to tune it out.. but wouldn't that slow down the spool up ?
When I was playing around I got some things to work... I used a turbosmart bleed valve in the boost line to restrict it... then played around however It didnt make sense until now you tell me that the boost maps are back to front... That makes sense... I did find that the adjustment that I could get was limited due to the stock actuator the spring simply was not cutting it...
So I set my actuator at 12psi with a tie rod putting more preload on the wastegate and then adjusted it to 15psi using a modified gated T valve... without jets in the boost system...
result getting on boost at around 2K... Pretty good hey... have not tested when full boost comes in... think it is about 4K but that sounds a bit late... might need to go and give it a hit... but there a crack downs on hooning and stuff so I am a little paranoid... a few deaths in NSW.. I think they are bringing in car crushing too...
I think it is time to go off to the dyno... but have a look at the maps and let me know what you think...
P.S my map has AFR and BOOST thanks to MAT and my DLP converter..
What size spring is in your actuator on the 2871 ? if it is set to a minimum of 8 psi and you are tuning it to say 20... I think your actuator may need a tweak as the exhaust gas will blow open the wastegate and spike your boost... you might be able to tune it out.. but wouldn't that slow down the spool up ?
When I was playing around I got some things to work... I used a turbosmart bleed valve in the boost line to restrict it... then played around however It didnt make sense until now you tell me that the boost maps are back to front... That makes sense... I did find that the adjustment that I could get was limited due to the stock actuator the spring simply was not cutting it...
So I set my actuator at 12psi with a tie rod putting more preload on the wastegate and then adjusted it to 15psi using a modified gated T valve... without jets in the boost system...
result getting on boost at around 2K... Pretty good hey... have not tested when full boost comes in... think it is about 4K but that sounds a bit late... might need to go and give it a hit... but there a crack downs on hooning and stuff so I am a little paranoid... a few deaths in NSW.. I think they are bringing in car crushing too...
I think it is time to go off to the dyno... but have a look at the maps and let me know what you think...P.S my map has AFR and BOOST thanks to MAT and my DLP converter..
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T28 should give 14psi at around 3200 - 3300rpm. 2871's are usually around 3500 - 3700.
That'll be one thing we'll be looking at on the dyno - boost response. We're going to try using the factory boost control solenoid and also a Turbotech ball-n-spring valve. The ball-n-spring valves give awesome boost response so that'll be the benchmark.
PL
That'll be one thing we'll be looking at on the dyno - boost response. We're going to try using the factory boost control solenoid and also a Turbotech ball-n-spring valve. The ball-n-spring valves give awesome boost response so that'll be the benchmark.
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
will have to check mine in a little more detail... I think it is just a bushed t28 not a BB ??? is there much difference ?PL wrote:T28 should give 14psi at around 3200 - 3300rpm. 2871's are usually around 3500 - 3700.
That'll be one thing we'll be looking at on the dyno - boost response. We're going to try using the factory boost control solenoid and also a Turbotech ball-n-spring valve. The ball-n-spring valves give awesome boost response so that'll be the benchmark.
PL
what did you think of those logs.... did you have a chance to look ? also a little off the subject is his nats working ??? with the new CPU... and is it still running the same firmware as mine ? if so have you any more of those boards... cause I have another CPU to get done...
chris
I've actually noticed very little difference between the ball bearing and plain bearing turbos. I think it's mainly a durability thing - ball bearing turbos handle thrust loads much better.
I looked at the logs but I didn't know how to get boost values to come up.
Yes, Graeme's NATS is working. Same firmware as yours. All you need to do is make sure the correct base image is used (ie: 93F00 base image in 93F00 ECU). This is done by me anyway...
Currently good stocks of Type 4 boards.
PL
I looked at the logs but I didn't know how to get boost values to come up.
Yes, Graeme's NATS is working. Same firmware as yours. All you need to do is make sure the correct base image is used (ie: 93F00 base image in 93F00 ECU). This is done by me anyway...
Currently good stocks of Type 4 boards.
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
If you are in the log player in nistune you should be able to look at AUX1 or boost as I labeled it in mine maybe you need the DLP set up ? Matt can you comment ??PL wrote:I've actually noticed very little difference between the ball bearing and plain bearing turbos. I think it's mainly a durability thing - ball bearing turbos handle thrust loads much better.
I looked at the logs but I didn't know how to get boost values to come up.
Yes, Graeme's NATS is working. Same firmware as yours. All you need to do is make sure the correct base image is used (ie: 93F00 base image in 93F00 ECU). This is done by me anyway...
Currently good stocks of Type 4 boards.
PL
I opened it in excell and it as labelled aux 1...
maybe that can help... reading is in PSI...
I simply filled both the main and knock boost control tables with the same value all over - to give a flat boost curve. You just need to make sure that you change whole rows at a time. So if you want more boost at 3500, then you need to increase ALL the values on the 3500 row.
I can take a screengrab at home tonight if you want but it's not very exciting!
PL
I can take a screengrab at home tonight if you want but it's not very exciting!
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
hi pete,
Was thinking about your comment on the t28.. looking at it my boost is coming on a bit later... is this due to my massive FMIC and also my after market exhaust manifold ? and if so... is it better to open things up and flow better or just try to get on boost as fast as you can by shortening piping and keeping the cast manifold.. It seemed to drive better each time IMO however boost is at 3700 @ 15 PSI or is something else possibly wrong.. I will throw in the old boost valve and give it a tweak again cause I am keen..
Was thinking about your comment on the t28.. looking at it my boost is coming on a bit later... is this due to my massive FMIC and also my after market exhaust manifold ? and if so... is it better to open things up and flow better or just try to get on boost as fast as you can by shortening piping and keeping the cast manifold.. It seemed to drive better each time IMO however boost is at 3700 @ 15 PSI or is something else possibly wrong.. I will throw in the old boost valve and give it a tweak again cause I am keen..
Boost response can be a bit hard to nail down because it depends how quickly the car is accellerating. On the dyno they call this the "ramp rate" - I always use the same ramp rate on each car so that allows me to compare apples to apples.
On the road you really need to have the car properly loaded up to get an accurate reading. Usually 3rd gear going up a hill will do it. The more load the better - so take a mate or two! Second gear usually won't load them up enough and RPM changes too fast - not to mention wheelspin.
Be careful when doing road testing like this. It's really easy to have things get messy with turbo cars that are making a few HP. Always best to just pay the money and get it on the dyno.
Those Turbotech valves will always give the best boost response, sometimes at the expense of a small boost spike.
Typical T28 boost response :
http://www.plmsdevelopments.com/custome ... _c_psi.jpg
Typical 2871 boost response :
http://www.plmsdevelopments.com/custome ... _18psi.jpg
Bigger IC piping doesn't really seem to make much difference. A decent exhaust manifold should actually bring it on faster.
PL
On the road you really need to have the car properly loaded up to get an accurate reading. Usually 3rd gear going up a hill will do it. The more load the better - so take a mate or two! Second gear usually won't load them up enough and RPM changes too fast - not to mention wheelspin.
Be careful when doing road testing like this. It's really easy to have things get messy with turbo cars that are making a few HP. Always best to just pay the money and get it on the dyno.
Those Turbotech valves will always give the best boost response, sometimes at the expense of a small boost spike.
Typical T28 boost response :
http://www.plmsdevelopments.com/custome ... _c_psi.jpg
Typical 2871 boost response :
http://www.plmsdevelopments.com/custome ... _18psi.jpg
Bigger IC piping doesn't really seem to make much difference. A decent exhaust manifold should actually bring it on faster.
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
hey pete,
Changed the oil today.. gave it a good flush... That stupid VCT rattle... always lets me know when its time for a change... anyway to the point.. I put in the other ECU in my car... The boost transition is so much more powerful than the standard ECU.. I didnt play around with the boost yet just got the T in there... When do you add fuel... as soon as you get 0 manifold pressure you should be at 12.0 ? or different... with the nistune ecu I disabled the o2 feed back in the transition areas a little more and added fuel as I notice I was getting to 0 and still in the 14's on the wideband ?
Is there a rule ....
Changed the oil today.. gave it a good flush... That stupid VCT rattle... always lets me know when its time for a change... anyway to the point.. I put in the other ECU in my car... The boost transition is so much more powerful than the standard ECU.. I didnt play around with the boost yet just got the T in there... When do you add fuel... as soon as you get 0 manifold pressure you should be at 12.0 ? or different... with the nistune ecu I disabled the o2 feed back in the transition areas a little more and added fuel as I notice I was getting to 0 and still in the 14's on the wideband ?
Is there a rule ....
Hey Chris,
Been doing some playing with this myself. Got Graeme's car on the dyno today. Factory boost control rules. Almost as good response as ball-n-spring valve. But will allow you to hold boost towards the end instead of dropping off. Nice.
http://www.plmsdevelopments.com/custome ... botech.jpg
Power figures were pathetic though. Very disappointing. It made 200rwkw on 18psi. A 2871R should make nearly 220 at that boost.
http://www.plmsdevelopments.com/custome ... _18psi.jpg
I usually like to get mixtures on the rich side of 13:1 as soon as it's loaded up (0 psi). I tuned this one a tad rich cos not only didn't it make the power but it had a really bad tendency to detonate.
http://www.plmsdevelopments.com/custome ... 1_afrs.jpg
PL
Been doing some playing with this myself. Got Graeme's car on the dyno today. Factory boost control rules. Almost as good response as ball-n-spring valve. But will allow you to hold boost towards the end instead of dropping off. Nice.
http://www.plmsdevelopments.com/custome ... botech.jpg
Power figures were pathetic though. Very disappointing. It made 200rwkw on 18psi. A 2871R should make nearly 220 at that boost.
http://www.plmsdevelopments.com/custome ... _18psi.jpg
I usually like to get mixtures on the rich side of 13:1 as soon as it's loaded up (0 psi). I tuned this one a tad rich cos not only didn't it make the power but it had a really bad tendency to detonate.
http://www.plmsdevelopments.com/custome ... 1_afrs.jpg
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
200rwkw.. thats a bit dissappointing what torque figures were you getting... I would be keen to look at his z32 install to see how you did it...
Also what other mods has he done... you said FMIC, and clutch... what about T/B and manifolds ??
My car was pinging on the boost transition as I was saying earlier I moved the load scales in the mid section a little and it got rid of that.. however I am running a little fat in the middle with fuel... dont know if that was the right thing to do or not.. I did trim it a little... I am very impressed with your work on the stock boost control do you think you could get it to come on any faster ? I would like to see how it goes with a stronger actuator... like maybe a 1 bar minimum to see if it changes at all.. also what ramp rate are you testing at.. and how did you get your hands on a 1.4mm drill...
Also what other mods has he done... you said FMIC, and clutch... what about T/B and manifolds ??
My car was pinging on the boost transition as I was saying earlier I moved the load scales in the mid section a little and it got rid of that.. however I am running a little fat in the middle with fuel... dont know if that was the right thing to do or not.. I did trim it a little... I am very impressed with your work on the stock boost control do you think you could get it to come on any faster ? I would like to see how it goes with a stronger actuator... like maybe a 1 bar minimum to see if it changes at all.. also what ramp rate are you testing at.. and how did you get your hands on a 1.4mm drill...
Yeah, it's very disappointing I reckon. Well, it actually drives really nicely on the street - it goes hard. But for that turbo it should go better than that.
I took some engine bay pics but none really show the AFM. He's kept the engine bay looking really standard. Great job actually.
Manifolds are standard. But that shouldn't matter. TB is standard - I've been thinking about this. Does the S15 run the same little TB as the S14? If so then maybe this is the problem???
I don't reckon you'll get boost to come on any faster. The overlay of turbotech vs stock boost control shows this. The only way to bring it up faster would be to put a T28 on it!
I had a 1.4mm drill bit in my shed. I made up a set of jet drills years ago when I used to tune carbies.
Incidentally, we had to decrease that jet size even more. So it'd be more like 1.2mm now. We've still got a brass needle valve in there at present.
PL
I took some engine bay pics but none really show the AFM. He's kept the engine bay looking really standard. Great job actually.
Manifolds are standard. But that shouldn't matter. TB is standard - I've been thinking about this. Does the S15 run the same little TB as the S14? If so then maybe this is the problem???
I don't reckon you'll get boost to come on any faster. The overlay of turbotech vs stock boost control shows this. The only way to bring it up faster would be to put a T28 on it!
I had a 1.4mm drill bit in my shed. I made up a set of jet drills years ago when I used to tune carbies.
Incidentally, we had to decrease that jet size even more. So it'd be more like 1.2mm now. We've still got a brass needle valve in there at present.
PL
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chris2712au
- Posts: 343
- Joined: Thu Jun 19, 2008 1:52 am
- Location: sydney australia
He would be running a 48mm i think, best to get it bored and a 60mm throttle plate or If he wants to get a N15 sss t/b.. its a good upgrade but expensive...
machining is about 100 bucks and a n15 would be about 300 bucks..
I could possibly make you a throttle plate if you like but you would have to get the throttle body machined locally.. to fit it...
Also on the intake side to the turbo... that cast bend into the turbo is not so good.. Intake air changes direction too drastically... some improvements can definitely be made there..
Will see if I have some alu here and spin you one up..
machining is about 100 bucks and a n15 would be about 300 bucks..
I could possibly make you a throttle plate if you like but you would have to get the throttle body machined locally.. to fit it...
Also on the intake side to the turbo... that cast bend into the turbo is not so good.. Intake air changes direction too drastically... some improvements can definitely be made there..
Will see if I have some alu here and spin you one up..