BIG build

[futurevr4man]

well here is my thread about my build. im gonna try and keep it fairly updated, but no promises.

my current build:
3.1L forged pistons, rods, and crank
19t's
550cc's
blow through with 3.75" z06 maf
tuning with maf-t and safcII
built transmission
spec stage 5 clutch


what my plans are:
6g74 block
6g75 crank
forged pistons
forged rods
i m going dual 20g's hopefully full boost before 4k rpm's
my heads will not be stage 3 but they will be ported and polished with 272 cams
fuel will be my limiting factor because i will be out of money im sure. ill probably run my 550's at wastegate boost (12psi) for a while until i figure out what i wanna do

if you all have questions feel free to ask. i will update this post in the future to keep the info current. my goal is to have this done by winter of 2011.

go big or go home.

*edit* my "goal" was to have a 4L engine. after talking to ray about it, some things were not realistically doable for me, and other things were not reasonable financially. ill live with my 3.7L

[futurevr4man]

im going to preface this update: i am not sure how much attention this is getting, and im not really concerned. this is more for me than anything. with that being said, i am also hoping if i get some great results people can mimic what i have done and get some good results too. if i dont, then i guess you all will know what NOT to do lol

i did a lot of reading and nit-picking brains today. going to do more of it later, but i think i already have my answer.
gonna have the crank offset ground (like john monnin says to do on his website) down to 50mm bearings. this will serve 2 purposes:
1) give me 5 more mm of stroke thus another .2L (brings me a 4.04L engine)
2) make the bearing surface and bearing speed smaller. our engines already have issues with spinning bearings, i dont wanna cause more trouble for myself than necessary. also, i think the forged crank will be plenty strong with 50mm journals (stock 6g72tt size)

another benefit of this (and this is more theoretical than anything) is i will have a "square" engine. im not saying this is true or not, but all i know is some square engines in this world make some of the best power out of any of the engines ever made... examples:
- 2jztt
- W16 (in the veyron)
- SR20DE
- BMW S70/2 (in the mclaren F1)

so maybe there is something to it? you never know until you try.

what i think my specs will look like (this is without moving my piston wrist pin up at all)
95mm bore
95mm stroke (75 crank offset ground down to 50mm)
143mm connecting rods
probably aiming for 8.5:1 CR. might go to 9:1. more on that later

i would like to get my rods a bit longer.... the more piston speed i can slow down the better. its my #1 concern right now... im afraid it will put too much stress on the bearings.

-nate-

[eengler2]

What rods and pistons will you be using? I assume both will have to be custom for your build, correct?

[futurevr4man]

correct. its no more expensive to get them custom made as compared to buying forged ones anyhow though.

[Devilmightcry]

actually Over square engines make better HP but less TQ than under square engines with them same displacement. like f1 engines. 2jz will go under square when they stroke the engine.

[JasonY]

I'd personally stick with the 72 block and run the 74 crank instead or the 74/75 combo.

Jason

[futurevr4man]

Originally Posted by Devilmightcry

actually Over square engines make better HP but less TQ than under square engines with them same displacement. like f1 engines. 2jz will go under square when they stroke the engine.

right, i understand that. but considering we have understroked (over bored) engines from factory, it will be really interesting to see what happens when you stroke it this much.

Originally Posted by JasonY

I'd personally stick with the 72 block and run the 74 crank instead or the 74/75 combo.

Jason

with all due respect (and i really dont wanna come off snobby, thats not my intention) why the heck would you say that? what i am doing will:
1) not cost any more to do than the 72/74 combo
2) have a lot more displacement to play with
3) assuming it works, it will help people see another option with their engine

everyone talks about the build im doing, how many have actually done it? i know of 2, nelson and italo grasso... both of which make insane power. why would i not do it? i got a good deal on my turbos, block, and crank. the machine work will cost the same either way i go (more or less) as will the rods and pistons. im not afraid of it being a 74 and not dropping in, it wont be that hard.

thats my thought on it at least. i am legitimately curious if you disagree with that logic

-nate-

[Devilmightcry]

75 crank is not as strong as 74 so i'm not sure if it's good idea to cut 75 crank.

[MichaelMR2]

no it's fine

when it snaps, he can buy the 6g75 block in the holy grail thread, AND ray's stroker and make the first 4.2L V6 in 3000gt (AWD)

I'm curious to see new and interesting stuff no matter what results

[futurevr4man]

devilmightcry, you are basing that information off of what? trevors crank? how many 6g75 cranks have you ever even had in your hands? again, not trying to be rude, im just saying... you cant throw info like that around without something to back it up.

cutting the 75 crank journals will not affect the strength of it. trevor said his crank was flexing under the torque (came to that conclusion from the bearing wear)... he also said he was afraid of bad machine shop work (also because of the bearing wear). i have read through all of the threads about 75 cranks. no one, and i mean NO ONE knows how strong or weak they are. PLUS itallo grasso put down almost 800 ft-lbs on his with no issue...

its an awfully bold statement to tell someone that the #1 key part to their build is going to be too weak... can you back up your opinion with facts, examples, or even some thoughts on the matter? i am ginuinely curious... for all i know you are a master tech for mitsubishi or something


and MR2 W T F dude!! i need support here! it wont snap!