MTI 427 LS2 - 554 RWHP & 535 RWTQ, Long Read
04-22-2005, 10:35 AM
#1
MTI 427 LS2 - 554 RWHP & 535 RWTQ, Long Read Last night, I just tuned my friends 2002 Yellow Z06 Vette, damn what a car this is!!!
Yep that's right, 554 RWHP & 535 RWTQ!!!
Ok, story time.....
A little over a week ago is when all the fun began for me. My friend that lives in Columbus, OH had his MTI 427 LS2 long block installed by a friend of ours in Dayton, OH (Ohio Boys Racing). Once the car was all put together it wouldn't run at all on the MTI mail order tune. No big deal since I was going to do a full tune anyways on the C5. Since it wouldn't run, we decided to have the car flatbed to my house to the east side of Columbus.
Once I got the file downloaded I started going through it and made a few changes here and there. I uploaded the new file and started the car. The car ran like azz to say the least. After a few minutes of running the SES light came on so I checked the code. I got a "Cam Sensor Low Input Signal" code. After doing some checking on the car and then did a post on LS1tech.com, I found out that when you install a LS2 block in your LS1 car and extend the wires for the front mounted Cam sensor, you have to swap the 2 outer wires for it to work. It was wired straight, but not the fault of the installer; I would have done the same thing.
Once those wires got swapped, the car ran a lot better but had surging and died from time to time. I decided to look at the tune again and found a few things.
First, I had to add more to the Idle Air table and then I noticed the IFR table was a little on the low side. I pulled the fuel rail cover and saw that MTI put SVO 30lb injectors in this 427 LS2. I was like WTF, that's way to small of an injector for this engine. Long story short after talking to many people we all agreed that SVO 42lb green tops would be a lot better choice for this engine combo. My other friend that owns the dyno had a very slightly used set of 42lb injectors for sale so we bought them and installed them. I know that the injectors wouldn't help it idle better but they need to be in there anyways for the HP this engine was going to make.
I kept trying to get the car to idle and run and ended up calling MTI to see if they could help out some. Called them up and they asked if the throttle body blade had a hole in it and I said no, they said, it needs at least a 7/32" hole in it to make it idle. I never thought about that since it's a drive by wire and I thought I could tune for it. No matter what I did to the tables I couldn't get it. I drilled the hole and the car started right up and held idle fine. I started driving the car some but it had some surging and it would die at times, so I went to a 1/4" hole in the blade, which helped a lot more. Once in a while it had surging and it would die but was very rare.
Now that it was running good, I put some miles on it. As the miles started to add up, once in a while it started to have a squeal at idle. Now we are thinking belt, pulley, water pump. The squeal started to get worse and worse the more you drove the car. We started to get concerned so my friend took his car to a friend of his that worked at a car shop to get it checked out. He started looking into it, and when he tried to pull off the oil cap, he had a hard time getting it off, once he got it off the noise went away, put it back on noise came back. Pulled out the oil dip stick and the noise went away again. My friend was told that the PCV system was messed up. He called up MTI and told them what he found out and basically MTI forgot to send a new PCV system with this engine for the installer to put on. So MTI said they would over night the new PCV system to my friend to put on. In the mean time, MTI suggested a temporary fix by removing the current system and that worked fine. Now the car idles better and doesn't die and almost no surging.
Before I go any further I'll put up the mods:
- MTI 427 LS2 Short Block
- MTI STG 3 LS6 Heads
- S1 Cam 244 244 112lsa
- LS2 TB
- FAST Intake
- SVO 42lb Injectors
- C5 Cold Air Kit/Airbox
- 1 7/8" Kooks Headers
- Stock MAF
- Borla Catback
- Upgraded Clutch
- 3.73 Gears
- 160 Stat
- HP Tuners Tuned
- 11-1 CR
- Sunoco Ultra 94 Octane Pump Gas
We got over 500 miles on the car and changed the oil, now it's time for some dyno time. After we got the strapped down, I told the dyno operator to only take it to about 5,500 RPMS since I didn't know where the A/F was at. First pull, the tires just spun on the rollers! lol The owner of the car sat in the trunk so there would be more weight over the tires, that did the trick. That pull went to 5,550 RPMs, we got 520 HP & 501 TQ with a very rich A/F at almost 10-1. With leaning it out more and setting the timing to 25 degrees we ended up with 554 RWHP & 535 RWTQ with a A/F of about 12.2-1. Since this car doesn't have knock sensors I wanted to be a little conservative with the A/F and it will run a tad leaner on the street anyways.
The owner on the Z06 wants to put it back on the dyno in a few weeks to see if more miles will loosen it up a tad and make more HP. He told me last night that if he hit 525 at the wheels, he would be very happy. Let's just say he has a very big smile on his face right now.
I have tuned many LS1/LS6 cars over the past 2 years but this is my first 427 LS2 that I have ever tuned and I am in awe over the power this car makes. I'm not a shop just an individual that helps guys get an affordable tune in Central Ohio and surrounding areas. Within the next month, I have 2 other Z06 cars with pretty much the same set up that I have to tune. It's starting to look like Columbus, is going to start being like Houston, TX with a lot of high HP cars on the street and I'm glad that I can help make that happen! Thanks for reading all of this and please make note of all the issues I went through to get the 427 LS2 to work/run in an LS1 car. What an exciting time this is for the LSx based engines!
Bill
Yep that's right, 554 RWHP & 535 RWTQ!!!
Ok, story time.....
A little over a week ago is when all the fun began for me. My friend that lives in Columbus, OH had his MTI 427 LS2 long block installed by a friend of ours in Dayton, OH (Ohio Boys Racing). Once the car was all put together it wouldn't run at all on the MTI mail order tune. No big deal since I was going to do a full tune anyways on the C5. Since it wouldn't run, we decided to have the car flatbed to my house to the east side of Columbus.
Once I got the file downloaded I started going through it and made a few changes here and there. I uploaded the new file and started the car. The car ran like azz to say the least. After a few minutes of running the SES light came on so I checked the code. I got a "Cam Sensor Low Input Signal" code. After doing some checking on the car and then did a post on LS1tech.com, I found out that when you install a LS2 block in your LS1 car and extend the wires for the front mounted Cam sensor, you have to swap the 2 outer wires for it to work. It was wired straight, but not the fault of the installer; I would have done the same thing.
Once those wires got swapped, the car ran a lot better but had surging and died from time to time. I decided to look at the tune again and found a few things.
First, I had to add more to the Idle Air table and then I noticed the IFR table was a little on the low side. I pulled the fuel rail cover and saw that MTI put SVO 30lb injectors in this 427 LS2. I was like WTF, that's way to small of an injector for this engine. Long story short after talking to many people we all agreed that SVO 42lb green tops would be a lot better choice for this engine combo. My other friend that owns the dyno had a very slightly used set of 42lb injectors for sale so we bought them and installed them. I know that the injectors wouldn't help it idle better but they need to be in there anyways for the HP this engine was going to make.
I kept trying to get the car to idle and run and ended up calling MTI to see if they could help out some. Called them up and they asked if the throttle body blade had a hole in it and I said no, they said, it needs at least a 7/32" hole in it to make it idle. I never thought about that since it's a drive by wire and I thought I could tune for it. No matter what I did to the tables I couldn't get it. I drilled the hole and the car started right up and held idle fine. I started driving the car some but it had some surging and it would die at times, so I went to a 1/4" hole in the blade, which helped a lot more. Once in a while it had surging and it would die but was very rare.
Now that it was running good, I put some miles on it. As the miles started to add up, once in a while it started to have a squeal at idle. Now we are thinking belt, pulley, water pump. The squeal started to get worse and worse the more you drove the car. We started to get concerned so my friend took his car to a friend of his that worked at a car shop to get it checked out. He started looking into it, and when he tried to pull off the oil cap, he had a hard time getting it off, once he got it off the noise went away, put it back on noise came back. Pulled out the oil dip stick and the noise went away again. My friend was told that the PCV system was messed up. He called up MTI and told them what he found out and basically MTI forgot to send a new PCV system with this engine for the installer to put on. So MTI said they would over night the new PCV system to my friend to put on. In the mean time, MTI suggested a temporary fix by removing the current system and that worked fine. Now the car idles better and doesn't die and almost no surging.
Before I go any further I'll put up the mods:
- MTI 427 LS2 Short Block
- MTI STG 3 LS6 Heads
- S1 Cam 244 244 112lsa
- LS2 TB
- FAST Intake
- SVO 42lb Injectors
- C5 Cold Air Kit/Airbox
- 1 7/8" Kooks Headers
- Stock MAF
- Borla Catback
- Upgraded Clutch
- 3.73 Gears
- 160 Stat
- HP Tuners Tuned
- 11-1 CR
- Sunoco Ultra 94 Octane Pump Gas
We got over 500 miles on the car and changed the oil, now it's time for some dyno time. After we got the strapped down, I told the dyno operator to only take it to about 5,500 RPMS since I didn't know where the A/F was at. First pull, the tires just spun on the rollers! lol The owner of the car sat in the trunk so there would be more weight over the tires, that did the trick. That pull went to 5,550 RPMs, we got 520 HP & 501 TQ with a very rich A/F at almost 10-1. With leaning it out more and setting the timing to 25 degrees we ended up with 554 RWHP & 535 RWTQ with a A/F of about 12.2-1. Since this car doesn't have knock sensors I wanted to be a little conservative with the A/F and it will run a tad leaner on the street anyways.
The owner on the Z06 wants to put it back on the dyno in a few weeks to see if more miles will loosen it up a tad and make more HP. He told me last night that if he hit 525 at the wheels, he would be very happy. Let's just say he has a very big smile on his face right now.
I have tuned many LS1/LS6 cars over the past 2 years but this is my first 427 LS2 that I have ever tuned and I am in awe over the power this car makes. I'm not a shop just an individual that helps guys get an affordable tune in Central Ohio and surrounding areas. Within the next month, I have 2 other Z06 cars with pretty much the same set up that I have to tune. It's starting to look like Columbus, is going to start being like Houston, TX with a lot of high HP cars on the street and I'm glad that I can help make that happen! Thanks for reading all of this and please make note of all the issues I went through to get the 427 LS2 to work/run in an LS1 car. What an exciting time this is for the LSx based engines!
Bill
04-22-2005, 11:24 AM
#3
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Originally Posted by Good Doctor
30#ers in a 427 are plenty.
Those are killer numbers. Nice job.
04-22-2005, 12:08 PM
#4
Originally Posted by Good Doctor
30#ers in a 427 are plenty.
...Whether 30lb injectors (actually 34.6 with 58psi) are enough for a 427 is not the question. They are not enough for 554rwhp!!! I am only making 423rwhp and my injector duty cycle runs as high as 75%, NO WAY you can support an extra 130rwhp with that duty cycle...
Here is a good link giving a detailed java-based calculator to figure out injector limits...
http://www.rceng.com/technical.htm
#42 are (48 with 58psi) right were he needs to be, at 80% duty cycle
04-22-2005, 12:16 PM
#6
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I wouldn't say plenty more like maxed at 550rwhp assuming the fuel pressure is a constant 58 psi (which it is not).
I have mine with Racetronix PnP (255) + harness, Fuel pressure at 62 psi and i get lean at 550rwhp on N2O.
I have mine with Racetronix PnP (255) + harness, Fuel pressure at 62 psi and i get lean at 550rwhp on N2O.
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04-22-2005, 01:08 PM
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WOW, nice numbers!! Glad you got things worked out! Don't you think the 3KRPM and below is a little lean? Couldn't you pick up some power by adding a little fuel down low? Is that jagged line in that area detonation/knock? Either way, looks KILLER!
04-22-2005, 01:20 PM
#9
Originally Posted by Louis
RPM has more of a deciding factor than hp on injector.
With a 427, there is no reason to spin it to 7 like a 346.
30#ers would have been fine, 36#ers to be more than safe. 42#ers are overkill.
Regardless of how you did it, Good job
With a 427, there is no reason to spin it to 7 like a 346.
30#ers would have been fine, 36#ers to be more than safe. 42#ers are overkill.
Regardless of how you did it, Good job
554rwhp (652ish fwhp)?? At 110% possible duty cycle, sure.... I am using a B.S.F.C. of .47. Most NA motors are between .45 and .50...
Last edited by SideStep; 04-22-2005 at 01:29 PM.
04-22-2005, 03:18 PM
#13
I'm a little on the conservative side when it comes to things. As of right now, the LS2 knock sensors won't work with the LS1 PCM so I turned them off, that's why I am at 25 degrees of timing and a 12.2-1 A/F. It's really no different than the cars from the 60's and 70's, they didn't have knock sensors or Wideband O2s to use.
The lean spot you are seeing is just when you floor it, the air pump from the Wideband O2 has to catch up, all the cars that I have ever dyno'd, even stock cars show that on the graph.
Why go cheap on injectors? The above formula in that link is what I use to figure out what I really need. I have tuned a bunch of cars with SVO 42lb green tops and they work fine. When you have a $10,000+ brand new engine, why take the chance of an injector locking up because it reached 100% duty cycle. Better safe than sorry.
I forgot to add that he has a 255L in tank pump. His fuel pressure is rock solid, a little twitch when you get on it though, maybe 1-2lbs.
The lean spot you are seeing is just when you floor it, the air pump from the Wideband O2 has to catch up, all the cars that I have ever dyno'd, even stock cars show that on the graph.
Why go cheap on injectors? The above formula in that link is what I use to figure out what I really need. I have tuned a bunch of cars with SVO 42lb green tops and they work fine. When you have a $10,000+ brand new engine, why take the chance of an injector locking up because it reached 100% duty cycle. Better safe than sorry.
I forgot to add that he has a 255L in tank pump. His fuel pressure is rock solid, a little twitch when you get on it though, maybe 1-2lbs.
04-22-2005, 05:50 PM
#14
Originally Posted by Louis
Tell me then, what does your calculations say for a stock, 28# injector as the max?
http://www.rceng.com/technical.htm
This is a pretty funny thread considering it was Lou that recommended I go to 30# (34.6#) months ago when I bought my headers there... "keep your duty cycle below 80%" if I remember correctly... it is now 74-75% at the worst...
Originally Posted by Billiumss
Why go cheap on injectors? The above formula in that link is what I use to figure out what I really need. I have tuned a bunch of cars with SVO 42lb green tops and they work fine. When you have a $10,000+ brand new engine, why take the chance of an injector locking up because it reached 100% duty cycle. Better safe than sorry.
My apologies. Whats current IDC with the powerlevel now?
04-23-2005, 01:55 AM
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actually its not physically possible to have a injectors go past 100% since that is full open, when you datalog with EFIlive, and see over a 100 its a theoretical number that the program produces based on a formula.
BTW I am at 520 rwhp SAE(~537 uncorrected that day) and my IDC is about 78-80% at 12.5:1 AFR, SVO green top 42s.
can you use 30s with at car making 550 rwhp NA?, sure, how long will it last or how safe it will be is a different question.
Great numbers on the motor, thats is truly awesome power!
BTW I am at 520 rwhp SAE(~537 uncorrected that day) and my IDC is about 78-80% at 12.5:1 AFR, SVO green top 42s.
can you use 30s with at car making 550 rwhp NA?, sure, how long will it last or how safe it will be is a different question.
Great numbers on the motor, thats is truly awesome power!
04-23-2005, 06:05 AM
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427 Why would you go with a ls2 427
It has to be sleeved ,correct
A ls1 also has to be sleeved ?
c5r block no additional sleeves
I would think a 402 in an ls2 would make sense /no sleeves
This is just a question , and it refers to budget.
Mti c5r or 402 would seem to be more like stock bore
as in a 383 ls1 .
I guess I am not convinced on aftermarket sleeves
It has to be sleeved ,correct
A ls1 also has to be sleeved ?
c5r block no additional sleeves
I would think a 402 in an ls2 would make sense /no sleeves
This is just a question , and it refers to budget.
Mti c5r or 402 would seem to be more like stock bore
as in a 383 ls1 .
I guess I am not convinced on aftermarket sleeves
04-23-2005, 07:11 AM
#18
Originally Posted by Blktie8
Why would you go with a ls2 427
It has to be sleeved ,correct
It has to be sleeved ,correct
Jason at MTI told me there is a lot more aluminum around the iron sleeves and they can "scallop" the bottom of the new sleeves so the skirt of the piston does come out as far from the sleeve when it's at the bottom of the stroke, less piston rock.
Bill
but id much rather have the bigger bore (4.125) with a 4" stroke.....