New remote turbo thread
#166
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He was running 14lbs of boost on the 612 hp run. He also did some pulls at 7 lbs and those numbers look really good too. I think eventually his goal is to set the car up at 10 to 11 lbs and then start enjoying the car...
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Later,
Tom
89GT
82 Track Car in progress
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Later,
Tom
89GT
82 Track Car in progress
#167
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JT,
How much boost are you running and do you have a before dyno readout? Those are great numbers!
Dennis
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78 928 US 5 speed
78 928 Euro AT
81 931 5 speed
How much boost are you running and do you have a before dyno readout? Those are great numbers!
Dennis
__________________
78 928 US 5 speed
78 928 Euro AT
81 931 5 speed
10 lbs - 476 HP/ 526 torq
15 lbs - 612 HP/ 565 torq
Still lots of tuning to do with the ST both to optimize and protect....I agree with Louie on this for any forced air induction car, that ST tuning is necessary.
After the rebuild, the car (with 9:1 CR), pulled a fairly normal 270HP without the Rear Mounted Turbo
#168
Drifting
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Very impressive but the math is not coming out right, you are getting approx. 24.5hp per # of boost up to 7psi, then 11.3hp per # of boost up to 10psi and then 27.2hp per # of boost to 15psi? You might want to check your gauge as it may be reading high at midrange. I am usually seeing 500+ish rwhp at 10psi.
Overall you are getting approx. 22.8hp per # of boost which is what I would expect out of a well designed boost system.
Overall you are getting approx. 22.8hp per # of boost which is what I would expect out of a well designed boost system.
#169
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Meant to say this earlier... what a freaking awesome showing!
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So what was the A/R at 15 lbs of boost at max HP? The last 750 rpm was foregone because the A/R was leaning out, right? Also, can you measure the charge air temp? If it's super heated, water injection would be good for another 50+ hp.
The CR change makes a huge difference. Performance-wise, 7 lbs at 10:1 is about the same as 14 lbs at 9:1; at least it is in Saab-turbo-land. (I run 25 psi in my 9:1 SPG; custom turbo. My brother runs 11 psi in his 10:1 sleeper, using a stock mitsubishi TE05. The cars are nearly identically fast up to about 100 mph, and then I can pull away). Can't expect to run 15 psi on a 10:1 motor; not without water injection, the perfect turbo, and metal head gaskets anyway.
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So what was the A/R at 15 lbs of boost at max HP? The last 750 rpm was foregone because the A/R was leaning out, right? Also, can you measure the charge air temp? If it's super heated, water injection would be good for another 50+ hp.
The CR change makes a huge difference. Performance-wise, 7 lbs at 10:1 is about the same as 14 lbs at 9:1; at least it is in Saab-turbo-land. (I run 25 psi in my 9:1 SPG; custom turbo. My brother runs 11 psi in his 10:1 sleeper, using a stock mitsubishi TE05. The cars are nearly identically fast up to about 100 mph, and then I can pull away). Can't expect to run 15 psi on a 10:1 motor; not without water injection, the perfect turbo, and metal head gaskets anyway.
#170
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JT,
Are you using an intercooler? With the methanol and heat loss due to rear mount it may not be required. It is confusing that at 7 and 15 lbs you have gains of 9% per pound of boost, yet the 10 lbs run had less than 8% gain. Too much methanol?
Dennis
Are you using an intercooler? With the methanol and heat loss due to rear mount it may not be required. It is confusing that at 7 and 15 lbs you have gains of 9% per pound of boost, yet the 10 lbs run had less than 8% gain. Too much methanol?
Dennis
#171
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#172
Rennlist Member
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Seriously, though, what turbo is on there? No such thing as a perfect turbo... (one that generates no heat with its charge air and has no lag) but the variable vanes are purty durn close.
#173
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Very impressive but the math is not coming out right, you are getting approx. 24.5hp per # of boost up to 7psi, then 11.3hp per # of boost up to 10psi and then 27.2hp per # of boost to 15psi? You might want to check your gauge as it may be reading high at midrange. I am usually seeing 500+ish rwhp at 10psi.
Overall you are getting approx. 22.8hp per # of boost which is what I would expect out of a well designed boost system.
Overall you are getting approx. 22.8hp per # of boost which is what I would expect out of a well designed boost system.
#175
Official Bay Area Patriot
Fuse 24 Assassin
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Fuse 24 Assassin
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We have a standard 7 1/2 lb spring in the waistgate, with a dial up boost controller. With the boost control off at 7lbs we made 442.9 HP and just under 500 ftlbs torqe (4200rpm) and was also at 12.25 AFR we crossed to 11.8 AFR at 4600rpm and continued rich to 10.5 AFR into 6000rpm. With future tuning, we think we should be able to pull another 20-25 hp.
With that lower boost, is methanol injection still necessary to cool the charge air to avoid an overly lean state?
#176
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Andy,
He would probably be safe without methanol at 7.5 Lbs, but since he has a 9 to 1 CR any higher would be stretching it. My 931 has an 8.5 to 1 CR with a 1 bar boost and no IC or methanol and I have to be very careful to not run too lean. This happened 2 years ago when it developed a bad connection on the DITC and it cost more than $1,500 in repairs. i.e. I would consider the methanol cheap insurance.
Dennis
He would probably be safe without methanol at 7.5 Lbs, but since he has a 9 to 1 CR any higher would be stretching it. My 931 has an 8.5 to 1 CR with a 1 bar boost and no IC or methanol and I have to be very careful to not run too lean. This happened 2 years ago when it developed a bad connection on the DITC and it cost more than $1,500 in repairs. i.e. I would consider the methanol cheap insurance.
Dennis
#177
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FYI..ive got a snow perfromance kit just sitting on the bench here. Pump, resivour, 2 nozzles and a MAF controller. YOU would need new hose line and some of the nit picky hardware however.
$200
http://www.snowperformance.net/product.php?pk=9
$200
http://www.snowperformance.net/product.php?pk=9
#178
Supercharged
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Andy,
He would probably be safe without methanol at 7.5 Lbs, but since he has a 9 to 1 CR any higher would be stretching it. My 931 has an 8.5 to 1 CR with a 1 bar boost and no IC or methanol and I have to be very careful to not run too lean. This happened 2 years ago when it developed a bad connection on the DITC and it cost more than $1,500 in repairs. i.e. I would consider the methanol cheap insurance.
Dennis
He would probably be safe without methanol at 7.5 Lbs, but since he has a 9 to 1 CR any higher would be stretching it. My 931 has an 8.5 to 1 CR with a 1 bar boost and no IC or methanol and I have to be very careful to not run too lean. This happened 2 years ago when it developed a bad connection on the DITC and it cost more than $1,500 in repairs. i.e. I would consider the methanol cheap insurance.
Dennis
Theoretically, if you could control detonation reliably, you could run up to 30~40 psi of boost without issue. But if the motor started knocking at those pressures, something's gonna give and it won't be pretty.
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#180
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Andrew,
Besides detonation (fuel and ignition) running too high of boost on engines like our 928's can cause problems with head gaskets, pistons, rods and head studs. Too much boost with a standard compression ratio will cause the fuel to ignite without the ignition. i.e. you have a diesel. Even the standard 931 had beefed up components and they only ran 10 to 12 lbs of boost.
Dennis
Besides detonation (fuel and ignition) running too high of boost on engines like our 928's can cause problems with head gaskets, pistons, rods and head studs. Too much boost with a standard compression ratio will cause the fuel to ignite without the ignition. i.e. you have a diesel. Even the standard 931 had beefed up components and they only ran 10 to 12 lbs of boost.
Dennis