Tuning for faster spool
Jan 11, 2010, 02:13 AM
#91
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With regards to WRC, realize they are using a system that doesn't really work for normal driving and really can't compare to what we are doing.
They use a diverter valve that directs air from the compressor outlet to the turbine inlet. The ECU then dumps in extra fuel and retards the ignition advance. Rich mixture + late flame front + extra air in the exhaust manifold = full blown combustion in the exhaust manifold.
You ever see those jet engines made from turbochargers... Same idea.
They don't really have instant spool because of "tuning," they just never let the turbocharger shaft speed drop. It's always high and it's just a mater of closing that diverter valve to have full boost.
They use a diverter valve that directs air from the compressor outlet to the turbine inlet. The ECU then dumps in extra fuel and retards the ignition advance. Rich mixture + late flame front + extra air in the exhaust manifold = full blown combustion in the exhaust manifold.
You ever see those jet engines made from turbochargers... Same idea.
They don't really have instant spool because of "tuning," they just never let the turbocharger shaft speed drop. It's always high and it's just a mater of closing that diverter valve to have full boost.
the system works obviously well but costs much fuel and consumes parts fast. but who cares in a WRC car.
Jan 11, 2010, 05:46 AM
#92
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With regards to WRC, realize they are using a system that doesn't really work for normal driving and really can't compare to what we are doing.
They use a diverter valve that directs air from the compressor outlet to the turbine inlet. The ECU then dumps in extra fuel and retards the ignition advance. Rich mixture + late flame front + extra air in the exhaust manifold = full blown combustion in the exhaust manifold.
You ever see those jet engines made from turbochargers... Same idea.
They don't really have instant spool because of "tuning," they just never let the turbocharger shaft speed drop. It's always high and it's just a mater of closing that diverter valve to have full boost.
They use a diverter valve that directs air from the compressor outlet to the turbine inlet. The ECU then dumps in extra fuel and retards the ignition advance. Rich mixture + late flame front + extra air in the exhaust manifold = full blown combustion in the exhaust manifold.
You ever see those jet engines made from turbochargers... Same idea.
They don't really have instant spool because of "tuning," they just never let the turbocharger shaft speed drop. It's always high and it's just a mater of closing that diverter valve to have full boost.
Jan 11, 2010, 09:50 AM
#93
I beleive you can get the hardware components to pull it off using some EDM or JDM EVO 6.5 parts?
Like I said though, not too useful for a street car as I would imagine it's hard on parts.
I have to wonder if the "anti-lag" most of us use is worse though, considering it creates a lot of pressure surges where the other system is a bit smoother and probably keep the shaft acceleration rates lower.
Like I said though, not too useful for a street car as I would imagine it's hard on parts.
I have to wonder if the "anti-lag" most of us use is worse though, considering it creates a lot of pressure surges where the other system is a bit smoother and probably keep the shaft acceleration rates lower.
Jan 11, 2010, 09:53 AM
#94
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I don't think the "anti-lag" we use is actually for that purpose. As I am sure you are aware...it can add a margin of safety to an otherwise crappy tune.
Jan 11, 2010, 02:58 PM
#95
Are you talking about lean spool or anti-lag? The anti-lag we use would be the tephra launch control and it's fuel cut based.
The anti-lag I'm talking about I think there is a thread on it with a bunch of dissassembly. Never read it though as I have no interest in anti-lag on a street car. It actually allows the turbo to stay spooled even while the throttle is closed.
The anti-lag I'm talking about I think there is a thread on it with a bunch of dissassembly. Never read it though as I have no interest in anti-lag on a street car. It actually allows the turbo to stay spooled even while the throttle is closed.
Jan 11, 2010, 03:05 PM
#96
UK cars have the valve that sends air in the manifold, injectors can be tuned to send fuel thus creating ALS.
I have removed the OEM turbo setup for AMS thus removing the ALS valves etc; I have found retarding timing like I mentioned earlier gives the same results, turbo stays spooled and spools quicker.
Don't knock it until you have tried it.
I have removed the OEM turbo setup for AMS thus removing the ALS valves etc; I have found retarding timing like I mentioned earlier gives the same results, turbo stays spooled and spools quicker.
Don't knock it until you have tried it.
Jan 11, 2010, 03:16 PM
#97
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i could see low timing and more fuel for in between shifts could keep the turbo spooled thus full spool after a shift would be quicker. But on initial spool up you want more timing.
Jan 11, 2010, 03:56 PM
#99
One idea I've been toying with is a side by side intercooler and dual pass radiator setup. Half to reduce weight and polar moment, the other half just to improve overall cooling efficiency.
Garrett makes a 16"x12"x3" intercooler rated to 650 HP. While not the biggest thing out there, my power goals are well below 650 HP and it would leave just about the right amount of room for a cross flow dual pass radiator I came across. The advantage being that the lower IC pipe would be about a 6" long 45 degree bend into a low volume endtank. The intercooler is also smaller to reduce volume but still should provide good cooling. The outlet endtank would also be very low volume and the upper IC pipe would be about 2 1/2' long with a single 90 degree bend.
Garrett makes a 16"x12"x3" intercooler rated to 650 HP. While not the biggest thing out there, my power goals are well below 650 HP and it would leave just about the right amount of room for a cross flow dual pass radiator I came across. The advantage being that the lower IC pipe would be about a 6" long 45 degree bend into a low volume endtank. The intercooler is also smaller to reduce volume but still should provide good cooling. The outlet endtank would also be very low volume and the upper IC pipe would be about 2 1/2' long with a single 90 degree bend.
Jan 11, 2010, 08:48 PM
#101
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I've heard this -->http://www.bloxracing.com/product_in...products_id=21 helps. Probably going to pick one up and play with it.
Jan 11, 2010, 10:21 PM
#103
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There is a point of too little timing for spool too though (I think). Too much EGT and things start to melt.
The goal is to find the turbo's "happy place" where it spools quickly and early then hold boost to redline.
Maybe some others can post their examples of what they have done to tune for better spool and low end torque.
The goal is to find the turbo's "happy place" where it spools quickly and early then hold boost to redline.
Maybe some others can post their examples of what they have done to tune for better spool and low end torque.
Jan 11, 2010, 10:39 PM
#104
There is a point of too little timing for spool too though (I think). Too much EGT and things start to melt.
The goal is to find the turbo's "happy place" where it spools quickly and early then hold boost to redline.
Maybe some others can post their examples of what they have done to tune for better spool and low end torque.
The goal is to find the turbo's "happy place" where it spools quickly and early then hold boost to redline.
Maybe some others can post their examples of what they have done to tune for better spool and low end torque.
Jan 12, 2010, 04:11 AM
#105
Did anyone mention advanced intake cam/ retard exhaust cam timing? The turbo wants to be able to suck air in quick and exhaust it quickly with as little effort as possible. The hotter the exhaust gases the more volume they will consume allowing to move the exhaust wheel more efficiently. The trick is finding/creating that volume with EGTs in mind.