Just wondering what boost I should set/have with my truck fuel upgrades:

Glacier lift pump
90 HP injectors
TST
Smarty

The rest is in my sig.

Not enough boost will cause. . .? Or feel like?

Too much boost will cause. . .? Or feel like?

Anyone? Does the question make any sense?

 

Just wondering what boost I should set/have with my truck fuel upgrades:

Glacier lift pump
90 HP injectors
TST
Smarty Approx 60-70psi

The rest is in my sig.

Not enough boost will cause. . .high egt Or feel like A dog! Smoky mess

Too much boost will cause. . .Blown HG Or feel like Nothing Really.. Not much difference between the feel of 50psi and 90psi

Anyone? Does the question make any sense?

 

So 50psi up to 90psi you will not gain any more power? So you will be better off setting boost at 50psi?

The more fuel I add the more boost I need to match it? So with dual CP3's I may adjust boost to say 70psi to match the fuel? Of course, head studs, gasket, fire ringed heads are a must for boost increase, correct.

I should be safe up to 60 to 65 psi with my head studs, correct? Any more boost with my level of fueling would be inadequate?

 

Do you have an egt gauge? If egt's are in check, you don't want/need any more boost. A diesel will run all the way to a 28:1 air:fuel ratio. A diesel quits smoking around 22:1, and it will make lots of egts, smoke, etc at 18:1.

If you want more power, add more fuel! Power will continue to go up till you hit about 18:1. By then, your egt's are so high, you cannot tolerate any more fuel any way.

Your twins don't push much more air once boost hits a certain level, probably around 70 psi, but I do not know, others will have to comment on that limit. Once you push past the limit, you are pushing no more mass of air, just pushing the same amount at a much higher temperture= more gauge boost. So even if you're pushing 100 psi at 600*F, by the time it gets through the cooler it is down to 80 psi at 300* which is the same amount of oxygen as 70 psi at 200*. These are all made up numbers, my point is that you can only gain so much air flow by going up in pressure with the same size turbo.

 

With BD, or any, twins you take what you get. Not sure what you mean by "boost I should set"?
They are not really all that adjustable... unless you add a wastegate to primary turbo, or blow-off valves. You will probably see 60-65 psi. with your set up.

As stated, balancing act between fuel & air is not as complicated as your question suggests. 65 psi will support anywhere from 500 hp to say 750 hp easily; maybe more on a 3rd gen?

RJ

 

The smaller turbo is wastegated and adjustable. The large turbo is lowpressure.

I'll have to do some runs and see what my EGT's are. I believe they run a bit hot (1400*) when I really get on it. Yet I haven't yet set my mods to their full potential either. My boost gauge reads up to 40 and that's it. I'm still waiting for my A pillar gauges to arrive. Until then I won't know what boost I am at. So no adjustments just yet.

Thanks for the input, gentlemen!

 

With the mods that you have I would think you should see around 55psi of boost. The wastegate is adjustable, so see what your EGTs are like. If they are getting a little warm, then you can adjust it for more boost. On studs you are usually good to about 60-65psi.

 

Thanks Mr. Stewart.

By the way, great set of turbos. Easy installation. Even for a building contractor with very few hours.

Not that I am ready to upgrade (if ever -- haven't even began to work the turbos), but I was wondering if there is a another bottom turbo besides the 700 Race series to use in this compound. A bottom turbo between the s300 and s400, something for both towing and mild racing.

 

On our 2006 we have found the R700 kit to be quite tow friendly. It still has great throttle response and when you are looking for boost there is lots of it there. They would be a great upgrade for you.

 

How much more boost are we talking? I have head studs. Would I need head modifications with the 700 series turbos?

When I initially purchased the BD twins I was told the race series would not work well with towing. That is why I decided to go with the standard twins. I tow a 12000lb equipment trailer, but not all the time. I think I should have gone with my instinct and went with the larger bottom turbo.

I don't suppose BD would accept a trade in? I installed them a month ago.

 

What are your EGTs like now? Are you going to put more fuel to the engine? I am sure we can work out somthing to help you out if you are looking to go bigger.