Built LSX 427ci Troubles
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Joined: May 2012
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Built LSX 427ci Troubles Hi guys,
Just seeing if someone might be able to help me or point me in the right direction. I had an RHS Blocked LSX 427ci built in the US to go in place of an LS1. It just won't make any power. I mean 418whp (Dyno Dynamics) is all it will get. It sounds healthy will hold the power it does make to 7000rpm.
To give a bit of a comparison it local horsepower figures, an LS2 with a cam, valve springs, exhaust, intake, tune will make around the 420-430whp. An LS7 Corvette with a cam, shaved heads to 11.5:1 comp, exhaust, intake tune will make around the 560-570whp.
Anyway this engine is way off what it should make. I think I should be seeing around 550-600whp. It's also running E85.
Well these are the specs:
11.2:1 comp
RHS Block
4.125 bore
4.000 stroke
Callies Crank
Oliver Rods
Diamond Pistons
Brodix BR7 STS heads
1.8 Harland Sharp Rockers
Fast LSXR Intake
Fast 102mm TB
1 7/8 Headers 4-1's dual 3 inch exhaust
Comp Cam Specs are:
Valve Timing @ .50 int. open 12 BTDC close 58 ATDC
exh. open 64 BTDC close 18 ATDC
Gross Valve Lift .660 intake .660 exhaust
Duration @ .050 251 intake 262 exhaust
Lobe lift .3670 intake .3670 exhaust
Lobe separation 113.0
I have checked everything I could think of that could of been stuffed up for it not to make power. Checked cam timing, checked wiring, checked 100% throttle. Now I'm stuck. Either these cam specs are way off for what it needs or I am just jinxed.
If anyone could suggest anything it would be appreciated.
Just seeing if someone might be able to help me or point me in the right direction. I had an RHS Blocked LSX 427ci built in the US to go in place of an LS1. It just won't make any power. I mean 418whp (Dyno Dynamics) is all it will get. It sounds healthy will hold the power it does make to 7000rpm.
To give a bit of a comparison it local horsepower figures, an LS2 with a cam, valve springs, exhaust, intake, tune will make around the 420-430whp. An LS7 Corvette with a cam, shaved heads to 11.5:1 comp, exhaust, intake tune will make around the 560-570whp.
Anyway this engine is way off what it should make. I think I should be seeing around 550-600whp. It's also running E85.
Well these are the specs:
11.2:1 comp
RHS Block
4.125 bore
4.000 stroke
Callies Crank
Oliver Rods
Diamond Pistons
Brodix BR7 STS heads
1.8 Harland Sharp Rockers
Fast LSXR Intake
Fast 102mm TB
1 7/8 Headers 4-1's dual 3 inch exhaust
Comp Cam Specs are:
Valve Timing @ .50 int. open 12 BTDC close 58 ATDC
exh. open 64 BTDC close 18 ATDC
Gross Valve Lift .660 intake .660 exhaust
Duration @ .050 251 intake 262 exhaust
Lobe lift .3670 intake .3670 exhaust
Lobe separation 113.0
I have checked everything I could think of that could of been stuffed up for it not to make power. Checked cam timing, checked wiring, checked 100% throttle. Now I'm stuck. Either these cam specs are way off for what it needs or I am just jinxed.
If anyone could suggest anything it would be appreciated.
Im thinking cam as well. maybe your valves are not opening all the way. try putting the stock rockers back on it. 1.7 and re-size your push-rods with .080 preload. see if that helps. you can contact Patric G here on the forum for more info on this.
Have you done a leak down and compression test on the motor? The motor is cammed and headed to make 630+ Easy, and more like 650+ wheel. If compression and leak down look good, I'd look to the rockers and possibly going either to jesel's or reguiding your heads and going to stock LS7's w/ upgraded trunnions. Being that power is that low, I'd bet you find a weak cylinder or 2 during the leak down and compression test.
You might be slipping a clutch,if it flat lines at 418 and keeps it all they way up
CP and Leak down ect.. will help tell if the motor is good
With only 11,2:1 CP and fast 102mm it will be making 600-650rwhp not much more then that,cam is ok from the specs will not cause it to loose 200hp
No reason to use E85 on it,might loose power using it
CP and Leak down ect.. will help tell if the motor is good
With only 11,2:1 CP and fast 102mm it will be making 600-650rwhp not much more then that,cam is ok from the specs will not cause it to loose 200hp
No reason to use E85 on it,might loose power using it
My 408 pulled like a freight train way past 6300 making more and more power all the way to 7k.
I'm betting on pushrod length.
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What is the full drive train info? certain combos eat power or mess with the numbers, I had a 2001 Z28 that only put down 400rwhp but ran mid 10's on motor, the drive train combination messed with the dyno numbers bad !. How does it feel to drive ? like 400rwhp or 500rwhp ?
http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent
i think it's because you're running E85. it has lower energy output by around 30% compared to gasoline and also a much lower air-fuel ratio around 7-10 i believe which means to make the equivalent amount of power you need to force much more air into the engine. you're naturally aspirated, you say you make only 430 hp and expect to be around 630 hp. hey 30% whadya know. higher octane rating does not equal more power, not when other variables such as AFR and the energy content change.
what you're doing (in my opinion) is like running a diesel engine naturally aspirated without any kind of forced induction... your compression ratio can be up there at 20:1 however there's not enough air making it into the cylinder for the fuel to make the expected amount of power. if you want to run E85 then you need some kind of forced induction to get the necessary amount of air into the cylinder, it won't happen unassisted.
i think it's because you're running E85. it has lower energy output by around 30% compared to gasoline and also a much lower air-fuel ratio around 7-10 i believe which means to make the equivalent amount of power you need to force much more air into the engine. you're naturally aspirated, you say you make only 430 hp and expect to be around 630 hp. hey 30% whadya know. higher octane rating does not equal more power, not when other variables such as AFR and the energy content change.
what you're doing (in my opinion) is like running a diesel engine naturally aspirated without any kind of forced induction... your compression ratio can be up there at 20:1 however there's not enough air making it into the cylinder for the fuel to make the expected amount of power. if you want to run E85 then you need some kind of forced induction to get the necessary amount of air into the cylinder, it won't happen unassisted.
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From: Naples Fl.
Gasoline gallon equivalent - Wikipedia, the free encyclopedia
i think it's because you're running E85. it has lower energy output by around 30% compared to gasoline and also a much lower air-fuel ratio around 7-10 i believe which means to make the equivalent amount of power you need to force much more air into the engine. you're naturally aspirated, you say you make only 430 hp and expect to be around 630 hp. hey 30% whadya know. higher octane rating does not equal more power, not when other variables such as AFR and the energy content change.
what you're doing (in my opinion) is like running a diesel engine naturally aspirated without any kind of forced induction... your compression ratio can be up there at 20:1 however there's not enough air making it into the cylinder for the fuel to make the expected amount of power. if you want to run E85 then you need some kind of forced induction to get the necessary amount of air into the cylinder, it won't happen unassisted.
i think it's because you're running E85. it has lower energy output by around 30% compared to gasoline and also a much lower air-fuel ratio around 7-10 i believe which means to make the equivalent amount of power you need to force much more air into the engine. you're naturally aspirated, you say you make only 430 hp and expect to be around 630 hp. hey 30% whadya know. higher octane rating does not equal more power, not when other variables such as AFR and the energy content change.
what you're doing (in my opinion) is like running a diesel engine naturally aspirated without any kind of forced induction... your compression ratio can be up there at 20:1 however there's not enough air making it into the cylinder for the fuel to make the expected amount of power. if you want to run E85 then you need some kind of forced induction to get the necessary amount of air into the cylinder, it won't happen unassisted.
Right on it E85 makes more power then gasoline, all else being equal. I'm looking at PR length and the rocker arms for possible power loss sources, however this isn't a 600rwhp motor combination to begin with
if all else were equal then when i put E10 in any of my vehicles I would not get less fuel mileage then when using straight gas with no ethanol.
using E85 it just gets worse unless the motor was built to use it, and then you will be using more ethanol based fuel to make that power compared to gasoline because of ethanols lower energy content and lower AFR.
"Built to use it," lol that gave me a good laugh.
Fuel is fuel, and you're going to be slow forever with your train of thought. E85 will always make more power then pump gasoline. In some cases, it will make a LOT more power then pump gasoline.
93 octane has lower energy then 87 octane, but people don't slow down using it. Use your brain, and stay in school, kids.
Fuel is fuel, and you're going to be slow forever with your train of thought. E85 will always make more power then pump gasoline. In some cases, it will make a LOT more power then pump gasoline.
93 octane has lower energy then 87 octane, but people don't slow down using it. Use your brain, and stay in school, kids.
i disagree, E85 can make more power with all else being not equal.
if all else were equal then when i put E10 in any of my vehicles I would not get less fuel mileage then when using straight gas with no ethanol.
using E85 it just gets worse unless the motor was built to use it, and then you will be using more ethanol based fuel to make that power compared to gasoline because of ethanols lower energy content and lower AFR.
if all else were equal then when i put E10 in any of my vehicles I would not get less fuel mileage then when using straight gas with no ethanol.
using E85 it just gets worse unless the motor was built to use it, and then you will be using more ethanol based fuel to make that power compared to gasoline because of ethanols lower energy content and lower AFR.
Your energy figures are based on a per volume basis, but keep in mind to run where e85 wants to be in terms of air-fuel ratio, it will have more power than gasoline.
I actually ran the numbers once for fun, percentages are in terms of power.
Using straight 93 as the baseline
Straight 93@0.78 = 100%
93/meth = 99.5%
e85@0.78 = 104.2%
e85@0.73 = 111.4%
Fuel consumption for the e85 is about 30% more at the same equivalence ratio as compared to 93. Short story, you use 30% more fuel to gain 11% more power. Keep in mind this is just looking at the fuel and does not even touch the engine.
Anyway, this is getting a bit off topic. I would like to see the dyno graph of the car or even better a trap speed from a track.
I actually ran the numbers once for fun, percentages are in terms of power.
Using straight 93 as the baseline
Straight 93@0.78 = 100%
93/meth = 99.5%
e85@0.78 = 104.2%
e85@0.73 = 111.4%
Fuel consumption for the e85 is about 30% more at the same equivalence ratio as compared to 93. Short story, you use 30% more fuel to gain 11% more power. Keep in mind this is just looking at the fuel and does not even touch the engine.
Anyway, this is getting a bit off topic. I would like to see the dyno graph of the car or even better a trap speed from a track.
Chassis dyno? If it's a auto could be a very loose torque converter. Did you buy the engine assembled including heads and valve train? Also do you have a experienced tuner could be as simple as running out of fuel.