Welcome to Modern Mopar Forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.

Sign In Sign Up

Archived

This topic is now archived and is closed to further replies.

Rat Patrol

Turbo 6.4 Vs Turbo 6.1 - One For The Gurus

Started by Rat Patrol,

27 posts in this topic

Posted · Report post

A friend of mine down under is considering building a turbo gen 3.

He's unsure on whether to use a 6.1 or 6.4 but would like to know what differences ( if any) he can expect to find when using either long motor.

Cost will obviously swing in favour of a 6.1....but can we leave the initial purchase cost out of the deliberations.

Could you please advise on any significant differences he might encounter in building a 10 second 3600lb 6.1 vs a 6.4?

Comments appreciated on the folllowing:

Respective Block strength

Rotating assembly changes 6.1 vs 6.4

Cam selection 6.1 vs 6.4

Valve train specs and issues

Commercially available kits?

Best choice turbos?

Best cost effective EFI AND spark controllers

I believe he intends to retain the factory EFI hardware.

Your input is appreciated.

0

Share this post

Link to post
Share on other sites

Posted · Report post

This is what we need to know - do we empty both motors out over a bin and start again, or which parts are viable using FI?

For example...are the rods stronger in a 6.4 than a 6.1 and if so, will they stand up to FI use?

Are there issues with either motors slugs?

What about VVT and what is the problem when using FI?

Are the factory dampers up to the job?

Pretty clear on 6.1 valve springs and pushrods...but what about 6.4?

Oiling mods that would be necessary in either motor?

As you can see, we really need a primer on what can be used and what needs replacing / modding from the pan to the Throttle body....

0

Share this post

Link to post
Share on other sites

Posted · Report post

This is what we need to know - do we empty both motors out over a bin and start again, or which parts are viable using FI?

For example...are the rods stronger in a 6.4 than a 6.1 and if so, will they stand up to FI use?

Are there issues with either motors slugs?

What about VVT and what is the problem when using FI?

Are the factory dampers up to the job?

Pretty clear on 6.1 valve springs and pushrods...but what about 6.4?

Oiling mods that would be necessary in either motor?

As you can see, we really need a primer on what can be used and what needs replacing / modding from the pan to the Throttle body....

Still didn't answer my question

0

Share this post

Link to post
Share on other sites

Posted · Report post

I'd avoid the VVT due to tuning issues and your ability to go to a proper sized cam for boost without a lot of drama. 10 second car....auto or stick? I'd be a bit more specific about the level of boost you're targeting and what the forced induction system might amount to....single or dual, controller, etc... Is it extreme or just a 10-12 psi build? Turbo placement might not be a bad idea to work also.

If it were me, I'd start with a 6.1 block, install a forged rotating assembly using a Scat crank, 2618 Mahle pistons and you have options on the rods depending on how much power you're looking for. You can build the heads enough...definitely springs to handle the cam and depending on boost, valves to vary. Nice turbo cam. KISS is my advice...at least as much as possible with the complexity turbo brings.

Good luck.

HS

0

Share this post

Link to post
Share on other sites

Posted · Report post

Good points above. If you already have a 6.1 block that's what I'd use and make it stroked to a 392. It's pretty easy to get a auto at 3600lbs in to the 10s. A lot of guys with forged 6.1s and blowers at 4200+ lbs are running 10s.

0

Share this post

Link to post
Share on other sites

Posted · Report post

Andy - I think he plans on starting with a crate motor - but from what I'm reading..that could be a lot of $$ wasted on parts that aren't fit for purpose?

When you ask "Built" or "stock"...I kind of assumed you can't just throw a hairdryer on any of these motors and expect longevity...so I guess the answer is "as close to stock as is sensible"

So am I right in assuming that the minimum requirement would be to use a forged rotating assembly...with either motor?

Maybe what I should be asking is "What are the non-negotiables as far as changes to a stock 6.1 or 6.4-? " HemiSam has obviously addressed some of them...


If you are having these sorts of questions it would be smart of you to call a vendor on here such as Arrington or PWR.

Not really viable from 18000 miles away - and I think the guy is keen on doing as much as he can himself -but when he asked me which was the better motor to start with for a FI platform...I don't know enough about the 6.4 to answer him :unsure:

0

Share this post

Link to post
Share on other sites

Posted · Report post

Unless you're on the moon I doubt you're 18,000 miles away. Just sayin.

The global distance between New York and Melbourne, Australia is 18000 miles.

The global distance between Melbourne and London is 23,000 miles.

The Moon is 240,000 miles away.......Just sayin.....:P

1

Share this post

Link to post
Share on other sites

Posted · Report post

Anyhow folks - I learned today that they don't make a basic MP Crate 6.4 like they did with the 6.1.

The 6.4 that's available under 10K is a Chrysler replacement motor - and runs the VVT, MDS and active intake runner system - and from what I know, this mandates the use of the factory PCM and can cause real headaches - So I think his decision has been simplified.

So who makes the most cost effective 6.1 stroker kit?

0

Share this post

Link to post
Share on other sites

Posted · Report post

The global distance between New York and Melbourne, Australia is 18000 miles.

The global distance between Melbourne and London is 23,000 miles.

The Moon is 240,000 miles away.......Just sayin..... :P

Dude, just nod and say 'yep'. He's American.

lol

2

Share this post

Link to post
Share on other sites

Posted · Report post

You start to get an idea on how big the US, Australia and Canada are when you realise the distance between two of our cities (Melbourne and Perth) is the same distance as between London and Moscow!

I'm betting New York to LA would be the same.


You're all fucken slow

As it happens it seems I got the brief wrong........and my mate is talking 1000HP + - Would you mind providing a run down of the parts that went into your build? Brand of Rotating assembly, Which heads, Turbos, exhaust etc?

We coul really use some parts recommendations from those who are making big HP :)

0

Share this post

Link to post
Share on other sites
Go To Topic Listing Builds