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Advantages and disadvantages of a Barra compared to a single

PostPosted: April 18th, 2016, 12:44 pm
by Fingers
I’m just wondering what people think regarding the DOHC vs. the SOHC falcon 6.
At what power level are you better off with the Barra?
Are you better off sticking with the single cam engine?
There are examples of high quality 8, 9, and 10 second streetable single cam cars on this forum, and the Barra’s don’t seem to be any quicker……
Is it worth the time, effort, and dollars to change over when Michael and Justa6 can drive their single cam cars to the track, run a 9, and drive back home again?
Psi Pop has a Barra, and is also in the 9 second range, and there are some quality Barra builds that haven’t been to the track so no ET’s…..

I’m not trying to stir up a hornets nest, or open a can of worms.
Just after your thoughts, comments…

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 18th, 2016, 6:47 pm
by justa6
It really depends on how much power your chasing. I think twin cams do it a little easier, though there are plenty of tunnel vision cars punching out big numbers these days.

Twin cams have an endless supply of aftermarket parts and every workshop has a handful of them making good numbers.

When you start spinning a sohc hard, rockers can become an issue. Although I haven't had an problem yet, I should look at billet one's, which are expensive.

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 18th, 2016, 8:37 pm
by Jayedxr6
Sad but true, DOHC are in expensive, just find the whole bit or buy a wreck and with some simple bolt ons the cars good for some serious power right out of the box.

I'm staying SOHC coz I just like the idea of them in e series. That and I've got to many parts to get rid of lol.


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Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 6:10 am
by justa6
I wouldn't say twin cam are inexpensive. They have some expensive parts required were sohc aren't. Oil pumps, cam gears.

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 6:55 am
by mad_keen
Id say if your going for abit of power go dohc cause they handle a good amount half standard. If your going all out go which ever you want because you have to change everything in the engine no matter what.

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 11:11 am
by Jayedxr6
It's all bolt ons though Marty, no need to spend 1000$+ just on head work, replace Pistons and rods for anything over a mildly boosted engine, if your trying to achieve say 500wrhp, all the Barra really needs is valve springs.


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Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 11:12 am
by Jayedxr6
It's all bolt ons though Marty, no need to spend 1000$+ just on head work, replace Pistons and rods for anything over a mildly boosted engine, if your trying to achieve say 500wrhp, all the Barra really needs is valve springs.


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Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 6:37 pm
by GQuick
Farking dohc and their ease of modifications. Go SOHC ...that's what all the real cool kids do lol

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: April 19th, 2016, 10:25 pm
by Jayedxr6
Agreed^


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Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 5th, 2016, 6:12 pm
by pekkerwood
Hello
Not quite on topic, I have a el xr6 NA, bf gas rods, Mahle au forged flat tops .003 out the deck running 10.4 compression.

Would I be able to de shroud the combustion chamber to lower comp for turbo. I'm not chasing big power more of a high comp turbo build quick spool responsive street light racer 220 to 250rwkw. Thinking gtx3576r.

Thought I'd be happy with NA 165rwkw t5, diff 3.73 but sadly no, you boys are having to much fun, I want in. Thanks for any guidance

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 6th, 2016, 6:19 am
by Jayedxr6
Considering the Pistons sitting past flush I don't think the engine will last to long with the extra stresses of forced induction. Especially being well over 10:1 compression to start with.




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Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 8th, 2016, 7:24 pm
by pekkerwood
Thanks for the reply, I have no idea about turbos or sizing them. So with my 10.4 compression running 6to8lb boost on a small turbo gtx3076r with .63 and a large waste gate to minimise back pressure to get my 165rwkw to 220rwkw hoping it would be real quick on spool and linear power. Not chasing big power, standard t5 standard m78 is just a fanciful dream that will destroy my motor.

I purposely built my motor with minimal quench area so as to lessen the chance of detonation with the 10.4 compression. That's why I was hoping I could run a little boost, as stated I really don't know what I'm talking about trying to learn and looking at late model turbo cars they seem to run higher comps but I guess variable timing, better chamber design and better computers make it happen.

Does deshrouding the combustion chamber to gain cc's and lower compression work or does a big combustion chamber promote detonation thanks for any replies

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 9th, 2016, 9:52 am
by justa6
If you ran it on e85 and a good computer, you might be OK. Taking a little out after head will help. Probably easier to run a thicker head gasket or 2.

I wouldn't go smaller then a gt35

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 17th, 2016, 8:58 pm
by Michael (HYPOEB)
Stock for stock the dohc wins hands down! A mate of mine is running mid 9's in a heavy FG F6 with just bolt ons, valve springs and head studs, put that in a e series and you'd have a reliable 9 second street car. When shooting for bigger power it's all pretty much same same in my opinion. Both have been proven to work well, the key with a SOHC is to have the right knowledge involved in the build.

Re: Advantages and disadvantages of a Barra compared to a si

PostPosted: August 18th, 2016, 4:30 pm
by fordpatto
i agree.but something like rat's and ed40's look like a hell of a lot of fun.
and i'm glad that after all the shit you went through you found the right builder in jason.