Dutt neck - worth it?

[SuperSix]

Is this a viable upgrade over stock? Cost is $70 or so, then I would have to pay someone to weld it in..

Or just wait for a deal on a good used aftermarket SLIC/front mount?

[earlbrown]

Back when that was a common mod people used to report boost jumping up 3 or 4 pounds from that neck.

That tells me you'll loose 10 ~ 15 pounds of ex manifold pressure at the set boost level. That's always a good thing.


Even a good deal on a used SLIC will be a lot more than the $100 or so it'll take to upgrade the stocker.  Plus you can always sell it for more money with the neck on it when you find that good deal.


Before I bought the neck, I'd pressure test your stock intercooler first.  No reason to put a bunch of effort into a leaky core.

[SuperSix]

Back when that was a common mod people used to report boost jumping up 3 or 4 pounds from that neck.

That tells me you'll loose 10 ~ 15 pounds of ex manifold pressure at the set boost level. That's always a good thing.


Even a good deal on a used SLIC will be a lot more than the $100 or so it'll take to upgrade the stocker.  Plus you can always sell it for more money with the neck on it when you find that good deal.


Before I bought the neck, I'd pressure test your stock intercooler first.  No reason to put a bunch of effort into a leaky core.

Great info, just what I was looking for.

Thanks, Earl.

[Steve Wood]

Yep

Steve

[motorhead]

Your other option is something like this: http://www.ebay.com/itm/ALUMINUM-TURBO-35-x11-75x4-BLACK-FRONT-MOUNT-INTERCOOLER-KIT-2-5-SILVER-PIPING-/201078115194?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ed1308b7a&vxp=mtr

[deathraider6996]

See I've been wondering about those eBay intercoolers. Are they better than stock? Is it hard to mess up a intercooler design?. Are they worth their price?

Sent while curing depression with boost.

[Scoobum]

You pay for what you get. Either weld a Dutt neck on a stocker...or go with a good quality SLIC like a Precision etc.

[daveismissing]

Turbofabricator:
ACTUALLY.........The Dutt-neck ONLY gained 2 psi of boost due to Kenny having to re-clock the compressor housing to align with the new centerline of the larger neck. This, in turn, added more spring tension on the wastegate actuator. PERIOD! I have welded quite a few 2.5" Dut-Necks on over the years. They definately do not hurt performance, but I have found no substaniated gain other wise. Take a die grinder to the intercooler inlet and you can gain almost 1/2" of cross sectional area. The above info came directly from Kenny himself, shortly after he dyno tested the modification. I agree with Razor in that the CORE is the biggest restriction in the system. Step up to a PTE stock location intercooler for the best gains. (or other SLIC units available today.) The stock core is barely big enough to support 350HP. I know, I know they ARE alot of coin.

[SuperSix]

Hmmmm

[Steve Wood]

http://www.vortexbuicks-etc.com/ICtest.htm

Numbers are relative.  The two pounds drop in this test (the only near scientific test I have seen published) are a significant percentage given the magnitude of the numbers being compared.

One must keep things in perspective.  If we put a large turbo on a very fast car, the improvement would be miniscule if going from a stock IC to a big neck...but if we are talking about turbos of the 44 size on an average street car that is sneaking into the elevens, the improvement is more obvious.

Contrary to most internet commandos, one does not need a big IC or a three inch dp to run in the elevens...On the other hand, a steady supply of mullets is required to keep the Buick business in business...

[Steve Wood]

More food for thought, Grumpy edged into the Nines on V4...and it does not look all that impressive on the test linked above...just shows how dangerous it is to make assumptions based on apples and oranges particularly when it comes to numbers.


In answer to the question above about IC design...yes it is complicated as one is trying to balance flow versus heat reduction and get even air flow across the entire core to maximize affect....

[tb3]

I wonder why there hasn't been a GNX Dutt necked intercooler ever been available for the aftermarket? 
Seems like that would be the ultimate for guys that wanted to go stock-ish appearing and stock mounted

[granitestategn]

Turbofabricato r:
ACTUALLY.........The Dutt-neck ONLY gained 2 psi of boost due to Kenny having to re-clock the compressor housing to align with the new centerline of the larger neck. This, in turn, added more spring tension on the wastegate actuator. PERIOD! I have welded quite a few 2.5" Dut-Necks on over the years. They definately do not hurt performance, but I have found no substaniated gain other wise. Take a die grinder to the intercooler inlet and you can gain almost 1/2" of cross sectional area. The above info came directly from Kenny himself, shortly after he dyno tested the modification. I agree with Razor in that the CORE is the biggest restriction in the system. Step up to a PTE stock location intercooler for the best gains. (or other SLIC units available today.) The stock core is barely big enough to support 350HP. I know, I know they ARE alot of coin.

I'm confused by this one. Why would you have to re-clock the turbo to align it with the Dutt neck? I have mocked up my stocker on a piece of plywood as a jig and plan to cut off the stock neck and maintain the same centerline and distance when welding to the Dutt neck in place. I see no reason why this won't fit correctly. Why would you install it any other way?

[Steve Wood]

I am sure there has been...a GNX intercooler is the same one used on the TTA's....as I recall, the fin spacing is the only difference between the GN and the GNX/TTA


A couple of more comments-as is so often said, we get hung up on boost which is measured in psi but what counts is how many air molecules we can push into the cylinder which is air density.  Heating air thru the turbocharging process reduces the number of molecules in a cubic foot of air....when we intercool the air charge we are trying to recover lost air density which resulted from the compression of the charge.

Coincidentally, alcohol injection does the same thing...increa ses the charge density when it vaporizes and removes heat from the air charge.

The link I posted above from Bob Dick's test used a relatively small turbo-a TA49 as I recall.  It showed a reduction in pressure drop of about 2 psi across the core under the test conditions...a nd a corresponding improvement in flow coefficient of about 40% if I divided in the right direction...th at is about what the pressure drop reflects as well.

I think it is safe to say that the big neck is a pretty good bang for the buck in a mild combo that runs mid elevens...wher eas it is a paperweight on a Nine second car....add alcohol injection and it is perfectly adequate for most people unless they want to go down to the local Wawa and compare invoices.

It's all about apples and oranges

[Steve Wood]

Normally I would not expect to have to reclock it