What cubic inch is too large?
http://www.mastmotorsports.com/view.php?id=353&c=36&s=4
Launching!
Joined: Oct 2006
Posts: 201
Likes: 0
From: Grand Rapids, MI
Jack
then start over again..... When pushing an OEM Iron block that far I wouldn’t’ bore it at all. I’ve known many that had problems with cracking on a .030 bore with FI at lower power numbers than you are wanting. No OEM block is going to last many seasons at 1500WHP mark IMO. No reason a properly setup turbo engine needs the extra bore or stroke, just run more boost!
Fill the block. Run methanol, nice heads, and 40+psi. It'll make the numbers semi-reliably...
Fill the block. Run methanol, nice heads, and 40+psi. It'll make the numbers semi-reliably...
Last edited by Forcefed86; Dec 30, 2014 at 11:29 AM.
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I like my 370ci a lot. However the next motor I will be building will be a 427ci LSX block. I don't consider that you can go "all-out" and still have 4 bolt heads. My "all-out" will be with a 6 bolt block/head setup.
everybody is always saying to keep the Cubic inches small....but that is just plain wrong thinking....
More cubic inches always makes more power..PERIOD
the downside, is that you really need to pay attention to material between cylnders...
you really dont want to go bigger than a 4.03 bore or it starts to get kind of thin for boost
its hard to seal a head gasket if theres no meat to seal it with.
dont focus so much on the motor size, focus on how its built and how the exhaust is built to work with the turbos you want to use
a smaller cubic inch motor will want a smaller turbo
a bigger cubic inch motor will want a bigger turbo
same if you go with twins...
Twins are easier to route the downpipes as they are smaller, but they present their own challenges with physical space for the turbos themselves
a single turbo is easier to place, but the bigger down pipe makes exhaust plumbing more limited.(which often leads to fender exit exhaust)
and if somebody tells you it will be laggy...consider why...improper turbo sizing is the cause...not anything from engine size
Turbo A.R matched to the motor is what makes it work...
More cubic inches always makes more power..PERIOD
the downside, is that you really need to pay attention to material between cylnders...
you really dont want to go bigger than a 4.03 bore or it starts to get kind of thin for boost
its hard to seal a head gasket if theres no meat to seal it with.
dont focus so much on the motor size, focus on how its built and how the exhaust is built to work with the turbos you want to use
a smaller cubic inch motor will want a smaller turbo
a bigger cubic inch motor will want a bigger turbo
same if you go with twins...
Twins are easier to route the downpipes as they are smaller, but they present their own challenges with physical space for the turbos themselves
a single turbo is easier to place, but the bigger down pipe makes exhaust plumbing more limited.(which often leads to fender exit exhaust)
and if somebody tells you it will be laggy...consider why...improper turbo sizing is the cause...not anything from engine size
Turbo A.R matched to the motor is what makes it work...
I went 4.125 x 3.75 for 400 cu in. Wanted to go with a shorter stroke, but didn't want to wait 3 months for a 3.27" crank shaft. Now that it's taken 7 months to get the heads done, I wish I'd have waited.
But in a lot of classes especially 275, most guys run more than a 400ci. Thats why I was asking in the first place.
But so far im pretty convinced that I will need an aftermarket block, so I might as well get the most ci and best stroke for my app.
But I see the norm always say that "more cubes makes more hp but is not really worth the money". The way I see it for example, if I spend $1k to gain only 25hp, thats still more usable hp IMO.
Correct me if Im wrong, I like learning.....
I think if i wanted to go "all out" on a production block a 4.030 bore and 3.900 stroke. Partial fill, 1/2 studs and LSA heads... anything more than that gets into aftermarket parts cost, and why go aftermarket head for deck thickness/sealing and not get 6 bolt, then you need a block to mate.
ok u can run 24lbs onna 364 or run 16lbs onna 416 and make the same power.. i rather make the same power and have less lag, boost #'s dont matter... HP does, and a 400+ cubic inch will eat 16lbs all day, everyone acts like your gunna have to run the same boost on a larger engine and you need beefier walls, but it doesnt matter especially a stroked motor, keep the beefy walls and more cubic inch and more power.. in the end they all work, but it seems no1 goes over a 427 onna repro block, so i guess that may be considered the biggest to go? Just build exactly what u want to meet your needs, a 4.8 will meet ur needs if you dont care about lag, just depends what you want
everybody is always saying to keep the Cubic inches small....but that is just plain wrong thinking....
More cubic inches always makes more power..PERIOD
the downside, is that you really need to pay attention to material between cylnders...
you really dont want to go bigger than a 4.03 bore or it starts to get kind of thin for boost
its hard to seal a head gasket if theres no meat to seal it with.
dont focus so much on the motor size, focus on how its built and how the exhaust is built to work with the turbos you want to use
a smaller cubic inch motor will want a smaller turbo
a bigger cubic inch motor will want a bigger turbo
same if you go with twins...
Twins are easier to route the downpipes as they are smaller, but they present their own challenges with physical space for the turbos themselves
a single turbo is easier to place, but the bigger down pipe makes exhaust plumbing more limited.(which often leads to fender exit exhaust)
and if somebody tells you it will be laggy...consider why...improper turbo sizing is the cause...not anything from engine size
Turbo A.R matched to the motor is what makes it work...
More cubic inches always makes more power..PERIOD
the downside, is that you really need to pay attention to material between cylnders...
you really dont want to go bigger than a 4.03 bore or it starts to get kind of thin for boost
its hard to seal a head gasket if theres no meat to seal it with.
dont focus so much on the motor size, focus on how its built and how the exhaust is built to work with the turbos you want to use
a smaller cubic inch motor will want a smaller turbo
a bigger cubic inch motor will want a bigger turbo
same if you go with twins...
Twins are easier to route the downpipes as they are smaller, but they present their own challenges with physical space for the turbos themselves
a single turbo is easier to place, but the bigger down pipe makes exhaust plumbing more limited.(which often leads to fender exit exhaust)
and if somebody tells you it will be laggy...consider why...improper turbo sizing is the cause...not anything from engine size
Turbo A.R matched to the motor is what makes it work...
