Dyno graph analysis
Discussion
Hi folks,
After having my little project Suzuki Cappuccino on the dyno I'm keen to have some of you dyno wizards out there analyse the graph.
For those who dont know, the cappo has a 657cc, 3 cylinder with a tiny little turbo attached to it. I did a CT9 turbo swap from a Toyota Starlet GT (1.3l) a custom exhaust manifold, turbo back 2.5" exhaust, bigger injectors, front mount intercooler and am using a monster sport N2 ecu which has been mapped for a larger turbo and injectors. It makes 75hp from the factory and considering its now making 106hp, I'm really happy with the percentage increase.
So my questions are, considering the turbo is plenty big enough for the CC of the engine and it is making good power, surely it should continue making boost right to the limiter? (with a small amount of boost drop expected) It just looks as though I'm loosing a substantial amount of boost higher up the RPM's.
Also I'd be interested to see if anyone can give some ideas for increasing power, and bringing boost in earlier would be a luxury. Maybe a larger inlet manifold?
According to the Starlet guys, the turbo is at its max at around 1 bar so maybe this is holding me back? The ECU is mapped to run at 1.2 bar ideally so possibly a fully customizable ecu might really get some good gains by perfecting the fueling and timing to match the turbo. The AFR's were checked when this setup was running on a previous car and they were pretty bang on. (From what I've been told that is.)
Happy to share more info on the set up if people are interested.
After having my little project Suzuki Cappuccino on the dyno I'm keen to have some of you dyno wizards out there analyse the graph.
For those who dont know, the cappo has a 657cc, 3 cylinder with a tiny little turbo attached to it. I did a CT9 turbo swap from a Toyota Starlet GT (1.3l) a custom exhaust manifold, turbo back 2.5" exhaust, bigger injectors, front mount intercooler and am using a monster sport N2 ecu which has been mapped for a larger turbo and injectors. It makes 75hp from the factory and considering its now making 106hp, I'm really happy with the percentage increase.
So my questions are, considering the turbo is plenty big enough for the CC of the engine and it is making good power, surely it should continue making boost right to the limiter? (with a small amount of boost drop expected) It just looks as though I'm loosing a substantial amount of boost higher up the RPM's.
Also I'd be interested to see if anyone can give some ideas for increasing power, and bringing boost in earlier would be a luxury. Maybe a larger inlet manifold?
According to the Starlet guys, the turbo is at its max at around 1 bar so maybe this is holding me back? The ECU is mapped to run at 1.2 bar ideally so possibly a fully customizable ecu might really get some good gains by perfecting the fueling and timing to match the turbo. The AFR's were checked when this setup was running on a previous car and they were pretty bang on. (From what I've been told that is.)
Happy to share more info on the set up if people are interested.
What type of boost control are you using?
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
I would say that the cams aren't matched to the changes you've made any more. Are they still stock?
Most of the engine seems happy with peaking out at about 7000RPM (wheel BHP is starting to drop off at that point), but it still seems able to go to 9000RPM.
Do you need the revs for top speed due to gearing or would you be happy with a lower rev limit?
Most of the engine seems happy with peaking out at about 7000RPM (wheel BHP is starting to drop off at that point), but it still seems able to go to 9000RPM.
Do you need the revs for top speed due to gearing or would you be happy with a lower rev limit?
And you cant just say a turbo is happy at 1 bar...on 2 totally different engines as on a 1.3 and 660cc the turbo is operating under different conditions.
Graph labelling is terrible. Is one of the traces even boost ?
And I'd say the CT9 could still be improved on. Lets face it, there are some minuscule turbos on diesels making much more power and something like that may well be better suited.
Although it'd all be trial and error.
Graph labelling is terrible. Is one of the traces even boost ?
And I'd say the CT9 could still be improved on. Lets face it, there are some minuscule turbos on diesels making much more power and something like that may well be better suited.
Although it'd all be trial and error.
Max_Torque said:
What type of boost control are you using?
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
I should of mentioned, i'm using a fairly basic manual boost controller. It's good as far as manual controllers go as its a spring and ball type as apposed to a bleed valve. No doubt a decent electronic controller would hold and build boost more reliably.As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
The cams are original still yes. I'll maybe look into aftermarket options from Japan.
The graph is pretty badly labeled I agree! The pink line you can see if boost which is sitting around 1 bar ish...
clemdobain said:
I should of mentioned, i'm using a fairly basic manual boost controller. It's good as far as manual controllers go as its a spring and ball type as apposed to a bleed valve. No doubt a decent electronic controller would hold and build boost more reliably.
No it wouldn't. B&S are basic, some are difficult to adjust precisely and can stick shut, but they have no problem holding or letting the boost build.So i'm going to look into getting some porting work done to open up the head as much as possible. The rev limit does need to be quite high due to gearing although if the boost came on earlier this could be dropped. The car drives amazingly just now and is ideally suited to track use where it will be used quite a lot, I don't want to push it beyond the realms of reliability as its not skipped a beat since the work was done but I would like a little more power if its not going to break the bank....
There's lots of info on engine tuning in general and some turbo specific stuff you should find of interest if you work your way through the archive of my old website.
https://web.archive.org/web/20110902010921/http://...
https://web.archive.org/web/20110902010921/http://...
clemdobain said:
Max_Torque said:
What type of boost control are you using?
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
I should of mentioned, i'm using a fairly basic manual boost controller. It's good as far as manual controllers go as its a spring and ball type as apposed to a bleed valve.As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
Max_Torque said:
clemdobain said:
Max_Torque said:
What type of boost control are you using?
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
I should of mentioned, i'm using a fairly basic manual boost controller. It's good as far as manual controllers go as its a spring and ball type as apposed to a bleed valve.As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
227bhp said:
Max_Torque said:
clemdobain said:
Max_Torque said:
What type of boost control are you using?
As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
I should of mentioned, i'm using a fairly basic manual boost controller. It's good as far as manual controllers go as its a spring and ball type as apposed to a bleed valve.As rpm and hence massflow increases, preturbine EBP increases, which blows open the wastegate, reducing boost pressure for a given actuator capsule pressure. Also, post turbine EBP increases, resulting in falling turbine efficiency and hence less compressor work.
As engine speed increases, and intake massflow increases, then the pre-turbine pressure increases (because more exhaust gas is trying to get out through the turbine). And, if the air capsule pressure is fixed (which it is with a dumb bleed type boost valve) then that rising pressure with engine speed must also act to make boost pressure fall!
Max_Torque said:
Typically a wastegate is a mechanically sprung penny valve. It is held shut by spring pressure and pushed open by both plenum air intake pressure AND preturbine exhaust backpressure. The minimum boost line is set (for any given spring preload) by applying all the plenum air pressure to the air capsule, so the valve is pushed open as early and as much as possible. A "boost controller" works by bleeding off some of that air pressure, so there is less force applied by the air capsule to open the valve. Hence the Max boost line is effectively just the pre-turbine EBP pushing the valve open.
As engine speed increases, and intake massflow increases, then the pre-turbine pressure increases (because more exhaust gas is trying to get out through the turbine). And, if the air capsule pressure is fixed (which it is with a dumb bleed type boost valve) then that rising pressure with engine speed must also act to make boost pressure fall!
So by 'Air capsule' you mean wastegate actuator (WGA) ?As engine speed increases, and intake massflow increases, then the pre-turbine pressure increases (because more exhaust gas is trying to get out through the turbine). And, if the air capsule pressure is fixed (which it is with a dumb bleed type boost valve) then that rising pressure with engine speed must also act to make boost pressure fall!
The WG is held shut by a spring in the WGA, if it is being forced open then it is the WGA which is too weak, not the boost controller, no?
You state that the type of boost controller in question somehow bleeds air off, but I can't see how this is possible as it only has two ports, neither of which is vented to atmos.
227bhp said:
So by 'Air capsule' you mean wastegate actuator (WGA) ?
The WG is held shut by a spring in the WGA, if it is being forced open then it is the WGA which is too weak, not the boost controller, no?
You state that the type of boost controller in question somehow bleeds air off, but I can't see how this is possible as it only has two ports, neither of which is vented to atmos.
You have drawn it without a vent, that doesnt mean they do not have a vent, which they doThe WG is held shut by a spring in the WGA, if it is being forced open then it is the WGA which is too weak, not the boost controller, no?
You state that the type of boost controller in question somehow bleeds air off, but I can't see how this is possible as it only has two ports, neither of which is vented to atmos.
227bhp said:
Max_Torque said:
Typically a wastegate is a mechanically sprung penny valve. It is held shut by spring pressure and pushed open by both plenum air intake pressure AND preturbine exhaust backpressure. The minimum boost line is set (for any given spring preload) by applying all the plenum air pressure to the air capsule, so the valve is pushed open as early and as much as possible. A "boost controller" works by bleeding off some of that air pressure, so there is less force applied by the air capsule to open the valve. Hence the Max boost line is effectively just the pre-turbine EBP pushing the valve open.
As engine speed increases, and intake massflow increases, then the pre-turbine pressure increases (because more exhaust gas is trying to get out through the turbine). And, if the air capsule pressure is fixed (which it is with a dumb bleed type boost valve) then that rising pressure with engine speed must also act to make boost pressure fall!
So by 'Air capsule' you mean wastegate actuator (WGA) ?As engine speed increases, and intake massflow increases, then the pre-turbine pressure increases (because more exhaust gas is trying to get out through the turbine). And, if the air capsule pressure is fixed (which it is with a dumb bleed type boost valve) then that rising pressure with engine speed must also act to make boost pressure fall!
The WG is held shut by a spring in the WGA, if it is being forced open then it is the WGA which is too weak, not the boost controller, no?
You state that the type of boost controller in question somehow bleeds air off, but I can't see how this is possible as it only has two ports, neither of which is vented to atmos.
1) any positive pressure in the wastegate capsule
2) any positive pressure in the exhaust manifold
With a manual boost "control" system, there is no way of compensating for the increasing exhaust manifold pressure (as engine speed increases) so boost will ALWAYS fall with speed when compared to the boost that can be made at a lower rpm.
Interesting reading! So I assume a electronic or "smart" boost controller would compensate for engine speed and regulate the amount of pressure applied to WGA? Any recommendations for a good controller and most importantly, what differences would I expect to see if the controller did allow boost to be held at higher rpm? Is the engine still at its peak at ~7k rpm or is it not making more power simply because its not able to hold full boost in the higher RPMs?
clemdobain said:
Interesting reading! So I assume a electronic or "smart" boost controller would compensate for engine speed and regulate the amount of pressure applied to WGA? Any recommendations for a good controller and most importantly, what differences would I expect to see if the controller did allow boost to be held at higher rpm? Is the engine still at its peak at ~7k rpm or is it not making more power simply because its not able to hold full boost in the higher RPMs?
Really depends on the sort of money you want to spend on a controller.All of these are decent, some more expensive than others obviously with different features and control options
http://gb-ent.com/gizzmo-electronics/gizzmo-ibc-r-...
http://gb-ent.com/gizzmo-electronics/gizzmo-ibc-r-...
http://shop.motorsport-developments.co.uk/gizzmo-m...
http://www.nengun.com/greddy/profec-oled
http://shop.motorsport-developments.co.uk/turbosma...
http://shop.motorsport-developments.co.uk/turbosma...
http://plex-tuning.com/products/pbc-pro-boost-cont...
I think ypu've already got the gist but I would also highly recommend using a good electronic boost control.
I used to use a 'Gizzmo' IBC - very good bit if kit, easy to setup and adjust, can run multiple boost levels etc, it worked really well.
I now have an ECU capable of controlling the boost, which is even better, can be tuned to give boost that rises with with rpm (making the engine feel like a big NA engine) or boost by gear to limit traction problems.
Final suggestion - make sure you set the boost controller up with the REFERENCE taken after any intercooler etc, but the FEED for the control solenoid taken from straight off your compressor housing.
I used to use a 'Gizzmo' IBC - very good bit if kit, easy to setup and adjust, can run multiple boost levels etc, it worked really well.
I now have an ECU capable of controlling the boost, which is even better, can be tuned to give boost that rises with with rpm (making the engine feel like a big NA engine) or boost by gear to limit traction problems.
Final suggestion - make sure you set the boost controller up with the REFERENCE taken after any intercooler etc, but the FEED for the control solenoid taken from straight off your compressor housing.
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