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View Full Version : HAHA the turbo project is back in full swing!



JLM
10-14-2005, 07:45 AM
Well after getting some things squared away with the car, the build, and just life in general I've decided to resurect the turbo project. Here's where I'm at. any suggestions would be greatly appreciated.

The engine in question is a 455 .030 over the the 455 "N" crank, forged rods and pistons (flat top at 0 deck). I will be acquiring a set of 4x casting heads with the 114cc chambers. This should put compression on a 462 at just over 8:1.

I will be utilizing the currendt edelbrock P4b intake that is on the engine. A set of custom built manifolds will hold a 40mm wastegate and either a T04b Vtrim or 60-1 on each manifold. an air.air intercooler will be utilized to cool the air charge.

An 850cfm holley dp modified for blow through will supply the fuel. I would like to remain using a mechanical pump in this setup but dependant on fuel requirements I may jump to an a1000 pump and a fuel cell.

As far as pressurizing the carb this is where I need some help. From my understanding carb tuning becomes much easier when there is no pressure difference from the inside to the outside of the car. This would mean building a carb box that enclosues the entire unit. However would feeding fuel from outside the carb box to with in cause problems? Should I just be looking at a normal carb hat?

Exhaust will be custom bent 3.5" downpipes into stock location 3" magnaflow exhuast with x pipe.

I'm shooting for 600-650rwhp on pump gas with this setup.

anything that I'm missing here? suggestions would be great. thanks.

ProStreet R/T
10-14-2005, 08:16 AM
Running fuel lines through car boxes is easy, just takes a regular AN bulk head fitting. Yes the carb will be much happier but they are rather bulky and somewhat of an eye sore.

I personally wouldn't rely on a mechanical fuel pump, do it right and go straight to the cell and electric pump.

I might raise the compression a bit, reason being is that your not going to spin that 455 much over 5500 i'm guessing. Kicking the comp up to low 9s will make it drive much better out of boost and you'll still be able to make a ton of power on pump gas.

JLM
10-14-2005, 08:24 AM
Running fuel lines through car boxes is easy, just takes a regular AN bulk head fitting. Yes the carb will be much happier but they are rather bulky and somewhat of an eye sore.

I personally wouldn't rely on a mechanical fuel pump, do it right and go straight to the cell and electric pump.

I might raise the compression a bit, reason being is that your not going to spin that 455 much over 5500 i'm guessing. Kicking the comp up to low 9s will make it drive much better out of boost and you'll still be able to make a ton of power on pump gas.

my only concern is the iron heads. The 455 benefits from a very large stroke in comparision to it's rod so it's got a nice helping of low-end torque. I may mil the heads to acheive a little under 8.5:1 but that would be as high as I would go.

So there isn't going to be issues then with fuel flowing from a line with normal atmoshperic pressure into a pressurised box then. As far as teh plumbing is conernced that wasn't an issue I can definitely design that into the box. My concern was with possible sideaffect from going from normal atmosphere to possitive pressure. I'm not building a show car so teh box being an eye sore isn't much of an issue. I'll probably build it out of alluminum and polish it anyway so it wouldn't look terrible.

What would you recomend as far as a pump goes? The holleys like around 7psi of fuel pressure at WOT correct?

ProStreet R/T
10-14-2005, 09:08 AM
Iron heads aren't the end of the world if the motor is setup properly. With the 455 it does have a killer long stroke, but also the largest main bearing dia (3.0 I believe) which really limits rpm potential. Thus my feeling that building a low rpm (5500 max) brutal torque monster would be perfect.

As for the holleys yeah they are happy in the 7-8psi range and you will need to have a gauge to verify they pressure the carb is seeing as boost will have an effect on it.

Check your PM's, I sent you a link to a place with tons of turbo info.

JLM
10-14-2005, 10:25 AM
I got yoru PM. I'm familiar with turbomustangs...after all I cam from 2 mustangs to this poncho.

annnnyway. About the carb enclosure. I do think for a reliable street blow-thru setup this is the way to go. The fuel lines won't be a problem but what do I do about the throttle linkage?

I've been racking my brain all day long with that one.I mean I could simply drill a hole in the enclosure and put a rubber gromet as a passway for the throttle cabloe. However there would obvsiouly be some boost leak there. What am I missing here to make this work correctly?

ProStreet R/T
10-14-2005, 10:48 AM
The carb box will have it's own linkage that connects to the carb and has an external cable mount and so forth. Similar to how a throttle body has a shaft running through it but doesn't experience any boost leaks.

This is about the best pic I could find.
http://hotrod.com/techarticles/79738

Whole article gives a pretty good understanding of how the system works.

JLM
10-14-2005, 11:23 AM
Okay that makes sense. I don't know if I'll personally be able to fabricate that so it might end up that I've got to purchase an enclosure. heh more $$$ That's okay it'll be worth it.

shmoov69
10-14-2005, 07:38 PM
I would go with a carb hat personally. The fast pressureized carb'd guys all run a hat. Either a CSU (like I got) or a Extreme Velocity (I think) bonnet seems to be the best. Sooooooo much easier to tune outside a box! Rember, think outside the box! There is not a problem with a hat other than if your throttle shafts are a little loose, you will get a little fuel stains streaking down the intake. Nothing a little carb cleaner won't get off. If that is an issue to you, you can drill the outside of the throttle shaft bore and run little vacum/boost lines to them to even the pressure on each side of the bushing. But carb cleaner is much easier!
My pump is an A1000, It definately keeps up!! Just be sure and run a 1/2" return back to the pump and get a GOOD boost referenced regulator. My little Mallory reg won't keep up and peggs the guage at 30psi when boost comes in. Needless to say, a little rich!
I know nothing about 455's, so cant help you there!

my72vette454
10-15-2005, 09:19 AM
I also run a CSU carb hat on my twin turbo setup and I modified my old 750 dbl pumper to work as a blow through and it runs great. I use an aeromotive a1000 pump also and I am using an aeromotive 13204 regulator with 5/8 supply and return line. It seems like I saw a new mechanical fuel pump in a new summit catalog that looks like it would do a good job with a turbo setup as long as you upgraded the fuel lines to go with it. It bolted in the stock location too.

Mike