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| 250 WHP Supernatural 3.4 Build (Page 22/47) |
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FieroWannaBe
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MAY 08, 09:53 AM
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| quote | Originally posted by La fiera:
Electric water pump set up will be next.
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For sustained RPM usage keep this in mind:
Following the 1/3,1/3,1/3 rule ( of total chemical power, 1/3 goes to the shaft, 1/3 goes to the exhaust, 1/3 goes to the coolant), this is often a typical starting point for system sizing. And 20 Deg F is the usual temp rise across an engine.
250 HP = 10602 BTU/Min
Flow (GPM) = Heat Rejection (BTU/Min) / [ Delta T (F) x Specific Heat (BTU/lb*F) x Density (lb/gal) ]
72 GPM = 10602 BTU/Min / [ 20F x .85 BTU/lb*F x 8.6 lb/gal ] (this is for 50/50 glycol/water)
Don't expect any electric water pump to cool very well at sustained high RPM circuit driving.
A standard 55GPM remote pump is capable of cooling an average sustained power level of 189 HP[This message has been edited by FieroWannaBe (edited 05-08-2018).]
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La fiera
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MAY 08, 12:55 PM
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| quote | Originally posted by FieroWannaBe:
For sustained RPM usage keep this in mind:
Following the 1/3,1/3,1/3 rule ( of total chemical power, 1/3 goes to the shaft, 1/3 goes to the exhaust, 1/3 goes to the coolant), this is often a typical starting point for system sizing. And 20 Deg F is the usual temp rise across an engine.
250 HP = 10602 BTU/Min
Flow (GPM) = Heat Rejection (BTU/Min) / [ Delta T (F) x Specific Heat (BTU/lb*F) x Density (lb/gal) ]
72 GPM = 10602 BTU/Min / [ 20F x .85 BTU/lb*F x 8.6 lb/gal ] (this is for 50/50 glycol/water)
Don't expect any electric water pump to cool very well at sustained high RPM circuit driving.
A standard 55GPM remote pump is capable of cooling an average sustained power level of 189 HP
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Straight water has nearly TWICE the heat transfer capacity as glycol-based antifreeze, and nearly 50% more heat transfer capacity than a 50/50 mix. This causes cooling systems containing glycol to run hotter. Heat is transferred from engine cylinder heads to coolant, and then from coolant to the external environment via the radiator.
That formula completely changes if straight water with a good anticorrosive additive is us used and add to that an oversized heat exchanger.
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FieroWannaBe
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MAY 08, 02:14 PM
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| quote | Originally posted by La fiera:
Straight water has nearly TWICE the heat transfer capacity as glycol-based antifreeze, and nearly 50% more heat transfer capacity than a 50/50 mix. This causes cooling systems containing glycol to run hotter. Heat is transferred from engine cylinder heads to coolant, and then from coolant to the external environment via the radiator.
That formula completely changes if straight water with a good anticorrosive additive is us used and add to that an oversized heat exchanger.
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That's just not true.
These all vary by temperature, but on average, for the ranges that concern us currently:
-Straight water has a specific heat of 1 BTU/lbF
-50/50 Glycol mix has a specific hear of 0.85 BTU/lbF
That is 15% less heat capacity, not 50%.
-The density of straight water is 8.1 lb/Gal
-The density of 50/50 is 8.6 lb/Gal
The volumetric heat capacity:
-Water: 8.1 BTU/GalF
-50/50: 7.31 BTU/GalF
That is a 10% difference in heat capacity by volume
Straight water:
65.4GPM needed flow for 250HP.
I edited this to remove my slightly complex response.
A radiator helps, but isn't the cure for a insufficient pump, which is most critical when duty cycle increases.[This message has been edited by FieroWannaBe (edited 05-08-2018).]
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Dennis LaGrua
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MAY 08, 03:41 PM
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| quote | Originally posted by La fiera:
I took the cover off my Fiero to look at how much space I have to see if I can pull the trans from the top and leave the engine in place, and while measuring I found this crack on the other side of the trans that I didn't see before! This means that the crack went all around! I'm thankful it didn't completely came apart while I was driving! |
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If you are making more than 200 ft lbs of torque you exceed the design limits of a Fiero manual transmission. I've seen many a Getrag and 4 speed blown in high demand applications. Also consider those boxes are 30+ years old. You can drop the trans leaving the engine in place and without dropping the entire cradle. You remove the tire and left strut, support the engine with a jack and hold in place w a 2 x 4 piece of wood, unbolt trans mounts, lower the rear of the cradle down just enough with a floor jack, disconnect clutch cylinder and shift linkage, remove trans bolts and pull the unit out of the left wheel house.------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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La fiera
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MAY 08, 04:49 PM
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| quote | Originally posted by Dennis LaGrua:
If you are making more than 200 ft lbs of torque you exceed the design limits of a Fiero manual transmission. I've seen many a Getrag and 4 speed blown in high demand applications. Also consider those boxes are 30+ years old. You can drop the trans leaving the engine in place and without dropping the entire cradle. You remove the tire and left strut, support the engine with a jack and hold in place w a 2 x 4 piece of wood, unbolt trans mounts, lower the rear of the cradle down just enough with a floor jack, disconnect clutch cylinder and shift linkage, remove trans bolts and pull the unit out of the left wheel house.
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Thanks Dennis
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Blacktree
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MAY 08, 05:24 PM
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I would not trust a 2x4 to hold up the engine. I would suggest 2x6 minimum.
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pmbrunelle
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MAY 08, 07:52 PM
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| quote | Originally posted by Blacktree:
I would not trust a 2x4 to hold up the engine. I would suggest 2x6 minimum. |
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A good quality 2x6 should be ok (good grade without knots), but it must be held vertically.
Using a square 6x6 would easily resolve the issue of having the 2x6 fall over on its side.
There must be electric water pumps that are big enough to meet the needs of track driving, no?
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La fiera
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MAY 08, 08:42 PM
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| quote | Originally posted by FieroWannaBe:
That's just not true.
These all vary by temperature, but on average, for the ranges that concern us currently:
-Straight water has a specific heat of 1 BTU/lbF
-50/50 Glycol mix has a specific hear of 0.85 BTU/lbF
That is 15% less heat capacity, not 50%.
-The density of straight water is 8.1 lb/Gal
-The density of 50/50 is 8.6 lb/Gal
The volumetric heat capacity:
-Water: 8.1 BTU/GalF
-50/50: 7.31 BTU/GalF
That is a 10% difference in heat capacity by volume
Straight water:
65.4GPM needed flow for 250HP.
I edited this to remove my slightly complex response.
A radiator helps, but isn't the cure for a insufficient pump, which is most critical when duty cycle increases.
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Your calculations are very good! In paper they look good with fixed variables, but if I change some fixed variables like a bigger radiator and oil cooler it's like changing the fixed variable "speed of light" in "c" in the E=mc2 formula and then everything changes.
I don't think I'll have a problem because the same electric pump I'll be using has been tried in another 240WHP turbo Time Attack car and the Aussie never had a problem.
But but if I do, which could happened because I can be wrong, I'll pull out the big guns. I'll increase the radiator capacity by tripling it with this radiator and a bigger oil cooler. This is a radiator from a 850HP Nascar, specifically from Kyle Bush's car. (I don't like him).
Got it for free from a friend that works for him as a fabricator. I'll also run the system in a "reverse flow" for better efficiency.
By the way, I tried the bigger pulley on the alternator and holy moly!!!! The engine revs so fast that my cheap tach can't react fast enough, it reads to 5000rpm and it misses.
As I looked at the MegaSquirt tach on the laptop it hits 7000rpm and misses. That miss is the rev limiter cutting spark and fuel!
Also it went from idling at 1100rpm to 1500rpm, definitely an increase in power.
The alt volts at 1500rpm are 12.5 but as soon as I touch the throttle pedal it jumps to 14.7 past 3000rpm. I snap the throttle half way and it hits the rev limiter! 
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La fiera
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MAY 16, 10:45 PM
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Some progress. New size battery installed!
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La fiera
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MAY 22, 06:33 PM
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My limited slip came today! 
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