Turbo Stroker DD going for economy
Posted: August 9th, 2015, 6:54 am
i'm in the middle of selling off my truck to down size to a Cherokee. the one i'm looking at needs an engine build and i have a plan. but have a few questions for the guru's out there
Engine outline
4.6L
96 block
Scat crank and Rods
Edelbrock head ported
Pistons to optimize head
9.5-10.2 SCR
Harland Sharp rockers (was considering trying to find 1.7 rockers??????)
Comp 68-231-4 or 68-232-4 cam or 68-235-4 (help)
Turbo
maybe water/meth but rather knock down CR
intended use as a casual off road/expedition vehicle and daily driver. so idle to 5000 rpm. looking to build a capable stroker thats efficient.
here are the issues i'm running into and need help with:
Turbo i've looked at several turbos T3/T04E ,GTX3576R, T3/60-1, T3/61, AGP Delta 52 and they all could work. i'm aiming for 10-12lb boost max but dont want to settle for 5-6.
http://turbocharged.com/catalog/compmaps/fig1.html
http://www.full-race.com/store/turbos/garrett-t-series/
http://www.agpturbo.com/agp-turbos/
https://www.turbobygarrett.com/turbobyg ... R&panel1-1
above are sources for the turbos i've been looking at. i'm not afraid to spend money on a turbo but if i can get the job done for less why not? realistically any of these turbos would work. my issue comes in when you start selecting the turbine housing. i've seen people use a .63AR or .83AR housing on 4.0L or 4.2L. last thing i want is a restrictive turbo that isnt doing its job efficiently. an option i was looking at was twin scroll housings. from what i've read they spool faster or more efficiently. if that's an option i can find .75 or 1.0 T3 twin scroll housings. i'm confident 1.0AR is way too big fro my application but think 0.75 might work.
help?
next point is cam selection.
when in a turbo application as long as you have an efficient turbo you shouldnt need extra exhaust duration. pressure on the intake should be close to the pressure on the exhaust side. but given how the head flows do i need that extra duration? if i was going to be normally aspirated i would probably pick comp 68-235-4 for the added duration and lift. i like the bigger lobe separation of the 231 and 232 and they have less overlap than the rest of the options with comparable lift.
whats a good turbo cam? do i need that added duration of the 235? what about 1.7 rockers?
head options.
from what i've read the edelbrock head is a blingy chunk of aluminum that flows comparable to a ported iron head.... what i like is the combustion chamber and would like to see if it will help with my goal for efficiency. i also like that its aluminum and will help me run a higher CR and try avoiding detonation issues (how high of a DCR can i run and still use pump gas?)
head question:
given this will be a turbo build is it worth just porting the head? port the head and bigger valves? or just port the head and only upgrade the exhaust valve to help get the gasses out of there? considering this engine isnt going to be a power monster or a screamer do i need to go with the bigger valves? my understanding is that flow is great but you still need velocity to atomize fuel and get the distribution for an even burn.
so to summarize...
what turbos have people used?
what turbine size are people using?
for a DD turbo stroker what cam have people used?
is porting the head and going with larger valves worth it in my application?
with an aluminum head how high can i go with my DCR on pump gas?
help...
i hope this all makes sense and we get some good information sharing. engine will hopefully get built this winter.
Engine outline
4.6L
96 block
Scat crank and Rods
Edelbrock head ported
Pistons to optimize head
9.5-10.2 SCR
Harland Sharp rockers (was considering trying to find 1.7 rockers??????)
Comp 68-231-4 or 68-232-4 cam or 68-235-4 (help)
Turbo
maybe water/meth but rather knock down CR
intended use as a casual off road/expedition vehicle and daily driver. so idle to 5000 rpm. looking to build a capable stroker thats efficient.
here are the issues i'm running into and need help with:
Turbo i've looked at several turbos T3/T04E ,GTX3576R, T3/60-1, T3/61, AGP Delta 52 and they all could work. i'm aiming for 10-12lb boost max but dont want to settle for 5-6.
http://turbocharged.com/catalog/compmaps/fig1.html
http://www.full-race.com/store/turbos/garrett-t-series/
http://www.agpturbo.com/agp-turbos/
https://www.turbobygarrett.com/turbobyg ... R&panel1-1
above are sources for the turbos i've been looking at. i'm not afraid to spend money on a turbo but if i can get the job done for less why not? realistically any of these turbos would work. my issue comes in when you start selecting the turbine housing. i've seen people use a .63AR or .83AR housing on 4.0L or 4.2L. last thing i want is a restrictive turbo that isnt doing its job efficiently. an option i was looking at was twin scroll housings. from what i've read they spool faster or more efficiently. if that's an option i can find .75 or 1.0 T3 twin scroll housings. i'm confident 1.0AR is way too big fro my application but think 0.75 might work.
help?
next point is cam selection.
when in a turbo application as long as you have an efficient turbo you shouldnt need extra exhaust duration. pressure on the intake should be close to the pressure on the exhaust side. but given how the head flows do i need that extra duration? if i was going to be normally aspirated i would probably pick comp 68-235-4 for the added duration and lift. i like the bigger lobe separation of the 231 and 232 and they have less overlap than the rest of the options with comparable lift.
whats a good turbo cam? do i need that added duration of the 235? what about 1.7 rockers?
head options.
from what i've read the edelbrock head is a blingy chunk of aluminum that flows comparable to a ported iron head.... what i like is the combustion chamber and would like to see if it will help with my goal for efficiency. i also like that its aluminum and will help me run a higher CR and try avoiding detonation issues (how high of a DCR can i run and still use pump gas?)
head question:
given this will be a turbo build is it worth just porting the head? port the head and bigger valves? or just port the head and only upgrade the exhaust valve to help get the gasses out of there? considering this engine isnt going to be a power monster or a screamer do i need to go with the bigger valves? my understanding is that flow is great but you still need velocity to atomize fuel and get the distribution for an even burn.
so to summarize...
what turbos have people used?
what turbine size are people using?
for a DD turbo stroker what cam have people used?
is porting the head and going with larger valves worth it in my application?
with an aluminum head how high can i go with my DCR on pump gas?
help...
i hope this all makes sense and we get some good information sharing. engine will hopefully get built this winter.