Turbo on a 408

Hey there....

It seems pretty obvious that turbos are the way to go if you want to go fast..

Would I get any good results using a turbo set up from a 5.9 cummins ?

Or if I have to go trough the whole 9 yards ?

I don't know much about turbo, that's why I'm here

I have 10.8 cr and Indy heads ported

Dan

The HX35 just isnt enough turbo for a healthy V8 gasser. Using a pair of them might get you some reasonable power though, there are just way better turboes out there better suited to a gasoline V8.

Didn't Cummins use several different size turbos on the 5.9 CTD?
I agree on not using just one designed for a small C.I. low RPM diesel motor on a car motor on gasoline with a lot less heat in the fuel to drive the turbos.
It is probably way better to have more boost than you really need

ok....so how about 2 for a dual quad set up ?

The problem with the cummins stuff is that they were designed to run a lot of boost. Most gas v8 motors aren't going to run that high. You could run two of them, but it's far from ideal.

The cost of the turbo itself is probably only 25% of your total bill to do something like this.

10.8 is pushing it, but with race has or alcohol you could do it. Not going to work very well with pump gas though.

What are your power goals? Remember it's more then just a turbo to make big power. You'll need a Trans, axle, chassis, and fuel system to keep up.

ok school me

If I was to run a single 4 bbl and go from 600 hp 553 lbs tq to 650-700 lbs tq...

Dan

Have a nice day.

If you got the compression down to 9:1, you could easily achieve those numbers with a setup like I use. Magnum exhaust manifolds and a Borg Warner S475 ($650 turbo) would get you there easy. You MIGHT be able to do it with one of the cheaper Chinese knock offs, but there aren't a ton of them out there with large turbine (exhaust) sides for a motor as big as a 408". You might choke the motor on the turbo before you get where you want to go powerwise.

Poly... respectively... A 71/75 would not make 1000hp on that motor, and you can find something that would work for a lot less then $1600.

The 408" needs quite a bit more then a 75mm on the turbine side to make 1000hp, and the 71mm compressor side would be absolutely set on kill to feed a 408" to 1000hp.

If you wanted that much power, The S475 I suggested with the 75/88 would be a good choice, or if you wanted more the Borg S480 with the T6 can be had for about $850. This has a 80mm compressor, with an 88mm exducer also on the turbine... Much better match for a bigger motor looking for 1000+hp.

The borg stuff is slightly on the heavy/large size, but they are about the best bang for the buck out there, and they are about bullet proof as far as turbo's go.

Ok.
So no turbo unit from any production vehicule would suit my need ? I have acces to cheap cheap supply of parts ! too bad......

Dizuster, my goal would be to gain at leats 150 lbs of torque....hp will come with it.
you suggest a S475?

Dan

There are lots of big rig turbos that you could use, but nothing off a regular pickup truck.

You can't just focus on torque with a turbo motor...it might make 700ftlbs at 3500rpm, and then choke at anything above that.

You'll need a hp goal to get the rpm range, to pick the turbo.

Ok I need 750hp

What is your opinion on the VS racing 80mm turbo? It is a S480 clone.


Ray

Not messed with a lot of turbos, but my experience with adapting diesel turbos to gas engines has not been good. The AR ratio and sizing of the turbo for the displacement of your engine is critical to make it work right. If I was to do a turbo, I would be to purchase an engineered kit, yes it is expensive, but so is blowing up engines. This article in Hot Rods gives you some idea of the issues with the cheap Chinese kits. Of course they are for a Chevy, but the idea is the same.
http://www.hotrod.com/articles/can-buy-small-block-turbo-kit-699-work/

Buy my s480 and I'll let you know lol


Demah just made 990whp with one on a stock bottom end 6.0

About the cheapest turbo off a factory rig would be off a Detroit. Its a Garrett TV8101. The one I had was 82mm. They will get to the 1000 hp range. Would work well on 400-500".

I actually have one of those I got from one of my customers years ago, what a heavy piece. The one I have is in pretty bad shape but it was free so I snagged it.

TV7512 is a good diesel option too for moderate engine size power.

The thing is with the TV's is they are REALLY big/heavy, old technology, and came in LOTs of variations... so you just have to know what you're getting before buying.

Viren (VS racing) is obviously getting his stuff from overseas like other distributors, but I have to say working with him he's a very good/honest person. Not a guy I'd be afraid to buy from. His S480 knock offs are about $50-$100 cheaper then the real thing, BUT come with a billet wheel too. So it really depends how good the billet wheel is if you want to risk buying one. Really too new to tell how much better they are then a regular cast wheel S480.

I have considered selling my single and going with a set of twins from VS was looking at the billet 78s. But I am also considering starting over with a R5 so I don't know.. lol

Interesting. I thought about twin S480's.




Ray

Twin s480s with good compressor wheels are probably 2200-2500hp capable!

Don't think two will fit in my engine compartment. i'm running a stock block also. At some point would like to pic you,and HOTMPR'S brain. 64 Dart wagon BB, push button trans.





Ray

Dizuster couple of questions.

Would the Dorman replacement magnum manifolds be okay?

At your power level/turbo what type of cam would you recommend solid flat, roller hyd/solid given the choice and what sort of duration and split/lift?

Dorman stuff is perfectly acceptable...no reason why they won't work.

My cam is pretty small. 230/235@.050", .540" lift on a 112lsa. Mine is a hydraulic roller, but I started with a roller block so it was cheap and easy to do. If I had an older block I'd use a flat solid. Turbo cams can be pretty mild and still make big power, so no need to do anything too crazy with it.

This is a good thread. I too am trying to learn about turbos. My 360 magnum spun a rod bearing and needs a rebuild. So I'm in the market for an upgrade.

Dizuster do you have a build thread or pics of your engine on moparts somewhere. I'd love to see as much as I could of your car.

Me too, I'm thinking I have a 400ci sitting in the garage........
Dan

rtt





I run the Dorman replacement manifolds on my turbo car. They definitely arnt as nice of a casting as the oem ones, but they've been holding up fine for 3 years now.

Not including junkyard turbo builds, it always seems to be that when turbo'ing v8 motors to go for maximum power, people tend to be to conservative on the turbo size. I know the turbo manufactures put the HP ranges on the turbos and sometimes it looks like a certain turbo would be way too big, but in real world, you have to really oversize the turbo to get big power results.
I agree the cam doesn't have to be overly aggressive either, more lift is good though.
I got most of my turbocharging experience in Japan, whats considered right for a motor over there is seen as gargantuan over here. Their favorite turbo for 2-3 litre class motors are turbos in the single 72-76mm range even for street car use(500-800 rwhp, pump gas). Add some more performance parts like flat shift transmissions, built motors etc and the turbo's go bigger yet. I run a 81mm turbo on a street car with a 2 litre motor.
I've watched a lot of turbo v8 builds on youtube and the power always seems kinda low when people are turbocharging 5 litre or bigger motors. I want to try a 400 B engine turbo project, but I don't really have any kind of chassis to put in.. I have a motor and pile of turbos laying around..
If I applied the Japanese tuning shop methods to it, it would be like this:
-shortest runner turbo manifolds possible(long manifolds kill power and increase spool time)
-Largest intercooler piping and intercooler I could get my hands on( this doesn't make lag, it cuts lag, it lets the engine breath to spool the turbo)
-port fuel injection with staged injection
-largest throttle body possible
-run twin 80mm minumum
-build engine to rev to 7000 rpm
-tall rear end gear
-6 spd close ratio transmission with flat shifting or 5 spd auto.
-best breathing heads possible
-Size the turbine so the W/G is wide open at target boost.
-low compression ratio around 8:1 (increased Mass flow rate, engine acts bigger than a higher compression motor)
I should start looking for a good D-150 to do the 400 build on with twin GT45's.. Maybe after I move shop to somewhere else.

I agree 100% with everything in that post until you get to the trans part.

Whats your thoughts on the transmission? After switching to a close ratio 6sp dog box, I'd never go back to a normal manual 5 speed or less transmission. The car is so much quicker flat shifting under boost without having to respool the turbo every shift like on OEM synchro'd boxes..Landing back right into the power band really makes the car faster. I went from keeping pace with modded turbo porsches to blowing right by them.
I suppose in drag racing minimizing your shifting reduces Et.

I am referring to drag racing. Road racing a turbo v8 is a nightmare. I have a perfect example of that sitting in my shop right now. WAY more power than any road race car needs or could use. 6 speed manual gear box. The car is horrible for road racing, and horrible for drag racing. It is now going to be used for top speed runs at various events. Anyway, when you are talking about V8s with large turbos, viable transmission choices dwindle. The broad tq developed by a turbo 8cyl simply doesn't need that many progressive gears to get it to move along. Doing so only makes the car more complicated and delicate.

The reason those little 2-3 liter motors can run such big turbos is RPM. They spin 9-10000 rpm. A lot different than a big block that goes 65-7000.

I've tried a lot of turbos on a lot of cars. Heck, I've tried a lot of turbos on my own car. I have learned that going bigger than suggested has always worked out better.

On my last setup peak power was 5500 rpm with 7200 rpm shift point. Most of the import 6's have a 4k-7k power band. The only cars I have seen that run over 9000 rpm are non turbo rotary motors.

Most of my experience comes pre-production development type applications, but our guideline is the pre-turbine hotside volume should not exceed 10% of the engine displacement. Granted this has a larger impact on street drive and manual trans cars, as a proper converter will allow you to spool regardless, however, turbines need both heat and flow, so the more heat you can push through the turbo, the better.

This may sound counter intuitive, but a compressor wheel that is to small for a specific application can cause more back pressure in the exhaust than a poor choice of turbine wheel/ A/R.

I don't see how that's possible? 360CID motor x 10% = 36CID. 2" pipe has a sq area of 3.13", meaning that you'd only get 11.5" of linear pipe to work with? You can't even connect both sides of the motor with 11.5" inches of pipe?

Did I misunderstand what you're saying, or is this more for single turbo 4 banger stuff?

More for single turbo 4 banger/twin turbo 6 type stuff, the point being, minimizing hotside volume can improve transient response. Not really a factor on drag stuff with loose-ish converters.

Agreed, the shorter the better. Some of the modern V8 diesels have the exhaust exiting into the valley of the engine with the turbocharger mounted there to reduce the pre-turbine exhaust volume too.

The best performing manifolds for import guys has always been the HKS or some of the Greddy stuff, they made their manifolds a different way(stake formed or cast) to minimize hotside runner length. Other people for the same motors used preformed fittings, and their manifold volumes and size were dictated by how their materials went together rather than what the turbo system really wanted.
The success of the HKS, Greddy, blitz etc turbos on imports was also because they did tons of R&D on Turbine/compressor balance to see what works best for the 2-3 litre class motors, their target market. Even though there are more efficient wheels out there now, nobody just off the shelf picking of the newer turbos is surpassing what was done with the now old HKS designs, which were Garrett centers sections altered and trimmed to fit HKS turbines and compressor housings.
Be nice if a big North American company would do the same for V8 applications, take a lot of the guess work away. A lot of people do get good results by buying a few hot sides and getting close, but how optimized are these setups? I don't think there is anything out there like a specifically trimmed turbo for 5-6 litre motors @ xxx rwhp etc.
On a sb or BB dodge the best option might be OEM style manifolds, rather than inverted long tubes. I can't remember if the BB manifolds are symetrical so they could just be turned upside down.




.

Oh cool. My buddy runs a turbo 4cyl eagle talon and hes in the 9000 range with a 80mm I believe..

"Hot V" has a couple of benefits. High end German gas motors are doing the same. Keeps the hot side short, keeps the volume pre-cat to a minimum for catalyst light-off, and heat naturally rises, so keep all the hot stuff high, in the same place. Most of the development now is centered on emissions. If you don't meet the requirements, you can't sell them (unless you are VW...)

This does create a nightmare for coldside plumbing, and separate TB's on each bank can create some torque model challenges.

And there is a "right" size for your coldside volume. It should be large enough to not evacuate and pull a vacuum when you go WOT before the compressor can build boost, but larger than that is just excessive weight, cost, etc.