4.8 turbo choice.....
4.8 turbo choice..... 2012 RCSB, 4.8, 4L60, 4x4
Here is what I'm thinking.....
212/218 sub .600" lift on a 112 + 2
Springs - 140# seat, 375# nose
Big treadstone or similar
Single 50mm bov
Lock up Yank or circle D (3000-ish)
Pump E85
Walbro E450 & 90lbers
And here is where I need some input....the turbo choice.
This will be a t4 flange...
MP70
On3 72
Big 366
S472
S475
...?????
I really don't want to spin it above 6500. And I'd like to get after the power early and let the convertor do its magic. Looking for a fat power band from 4k to 6k.
And as far as max power is concerned, I don't have a goal, I just want to push it pretty hard (700wheel ??).
What's your thoughts and suggestions ??
Thanks.....
.
Here is what I'm thinking.....
212/218 sub .600" lift on a 112 + 2
Springs - 140# seat, 375# nose
Big treadstone or similar
Single 50mm bov
Lock up Yank or circle D (3000-ish)
Pump E85
Walbro E450 & 90lbers
And here is where I need some input....the turbo choice.
This will be a t4 flange...
MP70
On3 72
Big 366
S472
S475
...?????
I really don't want to spin it above 6500. And I'd like to get after the power early and let the convertor do its magic. Looking for a fat power band from 4k to 6k.
And as far as max power is concerned, I don't have a goal, I just want to push it pretty hard (700wheel ??).
What's your thoughts and suggestions ??
Thanks.....
.
But yes, I'm somewhat aware of the typical 4L60 short comings.
Also, the truck may end up lighter than average....sourcing some 25lb 20x9's right now. Kind of JDM...but it is what it is....I've always been function over fashion type.
Thanks for the input.
.
Last edited by LSOHOLIC; Apr 21, 2016 at 02:41 PM.
Tires are 285/50-20....
.
My plans haven't changed....
Just not a fan of having a car down for years while I "save or decide" on the direction. Rather enjoy it while moving in a "general" direction. Which could be misinterpreted as "plans changed"...Still know one has said....
So.....if I want it all in by 6000 - 6500
What turbo ??
.
Trending Topics
If you have a weak drivetrain part, there are two big dangers when correcting for it,
1. you limit traction to some pre-set X value, i.e. you govern the resistance to some set maximum. And the force applied should be low rate of change, a gradual build, without slop or disengagement, each shift positively reinforces the previous gear in forward momentum in a gentle fashion.
2. this allow the engine to accelerate rapidly. This is the second danger. As you approach redline, you want to be limiting power output from the engine, not just the RPM at which fuel cuts, doing so will reduce the rate of change of RPM (decrease torque) to prevent catastrophic over-rev condition, and reduce computer/timing related phenomena.
For the dyno, this is not the case, no traction problems on a dyno means you can turn the boost up on the way to redline, have it raise instead of shut down to show power output potential. But I would not slam the motor against a fuel cut with such tremendous force, nor against a transmission clutch pack that I am trying to preserve.
1. you limit traction to some pre-set X value, i.e. you govern the resistance to some set maximum. And the force applied should be low rate of change, a gradual build, without slop or disengagement, each shift positively reinforces the previous gear in forward momentum in a gentle fashion.
2. this allow the engine to accelerate rapidly. This is the second danger. As you approach redline, you want to be limiting power output from the engine, not just the RPM at which fuel cuts, doing so will reduce the rate of change of RPM (decrease torque) to prevent catastrophic over-rev condition, and reduce computer/timing related phenomena.
For the dyno, this is not the case, no traction problems on a dyno means you can turn the boost up on the way to redline, have it raise instead of shut down to show power output potential. But I would not slam the motor against a fuel cut with such tremendous force, nor against a transmission clutch pack that I am trying to preserve.
Last edited by kingtal0n; Apr 21, 2016 at 02:12 PM.
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Verdad Gallardo Lol...OK. what is "yours" ??
My plans haven't changed.... Just not a fan of having a car down for years while I "save or decide" on the direction. Rather enjoy it while moving in a "general" direction. Which could be misinterpreted as "plans changed"...
Still know one has said....
So.....if I want it all in by 6000 - 6500
What turbo ??
.
My plans haven't changed....
Just not a fan of having a car down for years while I "save or decide" on the direction. Rather enjoy it while moving in a "general" direction. Which could be misinterpreted as "plans changed"...Still know one has said....
So.....if I want it all in by 6000 - 6500
What turbo ??
.
If you have a weak drivetrain part, there are two big dangers when correcting for it,
1. you limit traction to some pre-set X value, i.e. you govern the resistance to some set maximum. And the force applied should be low rate of change, a gradual build, without slop or disengagement, each shift positively reinforces the previous gear in forward momentum in a gentle fashion.
2. this allow the engine to accelerate rapidly. This is the second danger. As you approach redline, you want to be limiting power output from the engine, not just the RPM at which fuel cuts, doing so will reduce the rate of change of RPM (decrease torque) to prevent catastrophic over-rev condition, and reduce computer/timing related phenomena.
For the dyno, this is not the case, no traction problems on a dyno means you can turn the boost up on the way to redline, have it raise instead of shut down to show power output potential. But I would not slam the motor against a fuel cut with such tremendous force, nor against a transmission clutch pack that I am trying to preserve.
1. you limit traction to some pre-set X value, i.e. you govern the resistance to some set maximum. And the force applied should be low rate of change, a gradual build, without slop or disengagement, each shift positively reinforces the previous gear in forward momentum in a gentle fashion.
2. this allow the engine to accelerate rapidly. This is the second danger. As you approach redline, you want to be limiting power output from the engine, not just the RPM at which fuel cuts, doing so will reduce the rate of change of RPM (decrease torque) to prevent catastrophic over-rev condition, and reduce computer/timing related phenomena.
For the dyno, this is not the case, no traction problems on a dyno means you can turn the boost up on the way to redline, have it raise instead of shut down to show power output potential. But I would not slam the motor against a fuel cut with such tremendous force, nor against a transmission clutch pack that I am trying to preserve.
All very thought provoking.......and I was thinking more in the lines of a ignition cut (tq cut) at the shift point...talking in the 40ms range.
But, just got off the phone with the trans guy I've always used (he has several 8 second 4L60's and his personal 9 second 4L60 with over 50k on that build) He said he didn't think a clutch pack and ignition cut would last long.
So...he will go through it...he mentioned lots of hard parts...
Not to de-rail this deal.....what turbo ??
That "one guy" had very good luck with that larger bw366 (82/73) turbine wheel on a 4.8.
.
Would like it to begin falling around 6k
And a single is the only option...
Thanks.....
.
fuel cut is for longevity. Ignition cut is for racing applications where engine longevity is of no concern. when fuel is allowed to react in the exhaust system (as when we cut ignition) the pressure spike can move valves from their seats, floating them open and potentially bending them as the lobe/camshaft/pushrod become unpredictable with respect to contact with each other.
The pressure can help move a turbine, thus "boost building" is a feature of ignition cut, with emphasis on possible catastrophic destruction if the motor is not equipped for it. In a street app, fuel cut is the OEM/desired way to limit rpm in the case of an accidental over-rev. In fact, in my street car that I daily, I have the fuel cut RPM approx 800rpm before the natural OEM limit of the engine (about 6,400rpm in my app, OEM is 7200) this way missing shifts and accidental rear tire spins that peg the limiter are of no consequence, the engine just laughs. Naturally I would raise it on-the-fly if I wanted to dyno or race the car, its just a temporary safety net for solid reliability.
The pressure can help move a turbine, thus "boost building" is a feature of ignition cut, with emphasis on possible catastrophic destruction if the motor is not equipped for it. In a street app, fuel cut is the OEM/desired way to limit rpm in the case of an accidental over-rev. In fact, in my street car that I daily, I have the fuel cut RPM approx 800rpm before the natural OEM limit of the engine (about 6,400rpm in my app, OEM is 7200) this way missing shifts and accidental rear tire spins that peg the limiter are of no consequence, the engine just laughs. Naturally I would raise it on-the-fly if I wanted to dyno or race the car, its just a temporary safety net for solid reliability.
fuel cut is for longevity. Ignition cut is for racing applications where engine longevity is of no concern. when fuel is allowed to react in the exhaust system (as when we cut ignition) the pressure spike can move valves from their seats, floating them open and potentially bending them as the lobe/camshaft/pushrod become unpredictable with respect to contact with each other.
The pressure can help move a turbine, thus "boost building" is a feature of ignition cut, with emphasis on possible catastrophic destruction if the motor is not equipped for it. In a street app, fuel cut is the OEM/desired way to limit rpm in the case of an accidental over-rev. In fact, in my street car that I daily, I have the fuel cut RPM approx 800rpm before the natural OEM limit of the engine (about 6,400rpm in my app, OEM is 7200) this way missing shifts and accidental rear tire spins that peg the limiter are of no consequence, the engine just laughs. Naturally I would raise it on-the-fly if I wanted to dyno or race the car, its just a temporary safety net for solid reliability.
The pressure can help move a turbine, thus "boost building" is a feature of ignition cut, with emphasis on possible catastrophic destruction if the motor is not equipped for it. In a street app, fuel cut is the OEM/desired way to limit rpm in the case of an accidental over-rev. In fact, in my street car that I daily, I have the fuel cut RPM approx 800rpm before the natural OEM limit of the engine (about 6,400rpm in my app, OEM is 7200) this way missing shifts and accidental rear tire spins that peg the limiter are of no consequence, the engine just laughs. Naturally I would raise it on-the-fly if I wanted to dyno or race the car, its just a temporary safety net for solid reliability.
And all the street driving.....I have it setup to power the cut box anything over 5 mph. It is a manual gear box.
But been that way for 4 years....absolutely zero issues. Matter of fact, I love it.
What are you saying the durability issues with ignition cut are ??
.
Here is what I'm envisioning......
10psi = 500wheel @ 11.0x
20psi = 750wheel @ 10.4x
This would be in 4hi, thinking 1.5x sixties are manageable.
This thing should be under 4500lbs with me.
Lots of variables of course......
Would ultimately like the ivc and turbine side to max around 6k. With a 3.267 stroke and an ivc in the 36 - 38 range I feel 6k is on par. Now I need to find a turbine section that is on the same page.
.
10psi = 500wheel @ 11.0x
20psi = 750wheel @ 10.4x
This would be in 4hi, thinking 1.5x sixties are manageable.
This thing should be under 4500lbs with me.
Lots of variables of course......
Would ultimately like the ivc and turbine side to max around 6k. With a 3.267 stroke and an ivc in the 36 - 38 range I feel 6k is on par. Now I need to find a turbine section that is on the same page.
.
I run an ignition cut on my vette. N/A and spray.
And all the street driving.....I have it setup to power the cut box anything over 5 mph. It is a manual gear box.
But been that way for 4 years....absolutely zero issues. Matter of fact, I love it.
What are you saying the durability issues with ignition cut are ??
.
And all the street driving.....I have it setup to power the cut box anything over 5 mph. It is a manual gear box.
But been that way for 4 years....absolutely zero issues. Matter of fact, I love it.
What are you saying the durability issues with ignition cut are ??
.
I am saying that the fuel is exploding in the exhaust system, which can leverage open a valve at the wrong time. Ignition cut is notorious for floating valves on OEM spring engines. It is also additional wear and tear on turbochargers. Ignition cut is a kind of abuse, usually reserved for competition, where every ounce of energy counts, typically unacceptable rate of wear for daily driver engines. But as I have been told countless times already "most people on this forum barely drive their car 10,000miles, let alone 150k" Curious how many miles you have on the engine. Often, if an aftermarket spring is strong enough to withstand a high RPM ignition cut for years, it is also stiff enough to accelerate the wear/tear of the valvetrain beyond acceptable "daily driver" limits, facilitating "early rebuilds" and "20k mile head refurbishing" as a bland example.
Ok.....decided to give the on3 70mm a shot for this first swing.
But I would like to thank you guys for such a techy discussion...lol.
Really like the twin 118 comment.....don't let anyone tell you differently....trolling is king on this site !!
Thanks....
.
But I would like to thank you guys for such a techy discussion...lol.
Really like the twin 118 comment.....don't let anyone tell you differently....trolling is king on this site !!
Thanks....
.
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
The On3 70 should work well for your goals, should definitely get you to your 10psi/11sec goal.
The ignition cut vs fuel cut discussion is quite interesting, more research is required on my end before I can comment on either.
I second the Troll's notion for twin 118's.
The ignition cut vs fuel cut discussion is quite interesting, more research is required on my end before I can comment on either.
I second the Troll's notion for twin 118's.