well I'll give it a shot and others can chime in with additional info and corrections.

I think the question has to do with the effectiveness of the wastegate controlling device. Some argue that elevating the wastegate point causes the turbo to operate outside of its efficiency map (higher boost than it was designed for) -- which means that more boost is possible but may not give the expected benefit. In other words, the impeller spins only so fast before bad things happen mechanically, and the air pressure developed is hot air anyway. Beyond a certain point, the additional boost you develop isn't useful. the question is where is that point.

some box mfgs tell me they supply no boost fitting because their box generates enough boost as it is -- and they don't want to push the limit on the turbo (warranty). others supply a brass fitting and encourage its use because it allows you to eek out a few more HP.

As I read people's boost experience I've come to the following conclusions:

1. not all turbos have the same wastegate behavior. Some factory turbos allow high instantaneous boost pressures into the 30s (psi) with enough fueling.

2. Not everyone agrees as to the best wastegate point for the stock turbo. Some box mfgs (TST for example) supply a boost fitting tuned to the optimum wastegate setting for their box. others want the factory wastegate to control so the turbo isn't pushed out of its efficiency map.

3. with the small turbo supplied with the stock truck, additional boost (raising the manifold air pressure) isn't that effective. The small 9cm (about 3.5") exhaust housing and the 3.5" exhaust downpipe conspire for a restriction that is easily approached. with enough fueling (TST box on 9x9, for example) such high boost pressures are possible as to float the valve train. Air and fuel make power, not fuel and boost -- meaning that the additional boost only creates a higher pressure point on the intake manifold side -- if via increased airflow the turbocharger and downpipe (and exhaust manifold) themselves create a restriction then all you've done is stress the engine without adding much more air will flow.

4. The boost fitting question is one that balances usable HP, EGTs, and the longevity of the stock turbo.

 

Wow, you need to go to work , you've got way to much time for us dummies. Thanks, thats exactly what I was looking for. However, does not boost increase cylinder pressure (i.e. higher compression ratios on gas motors)? I understand the heat generated to power gain trade off. Have you ever seen anyone state the max efficient boost level for our turbos?

 

seems to me that boost would certainly increase compression pressures but not compression ratios (ratios are fixed by geometries). I'm not an engine designer so I may have to refer to someone else here!

as for the max boost for the stock turbo, I think TST recommends in the low 30s, maybe 35 tops not sure. Some of the guys who have experimented with this can probably jump in here with more relavent info. Thing is, you can make 40+ lbs of boost with a boost fitting, but I'm not sure it does you any good and thats working the little hy 35 pretty hard. From my reading, the low 30s are all I'd want to do.

The stress on the engine caused by higher boost would probably include the head gasket and the intercooler itself. come on guys you'll have to help me out here

 

Why are these so reasonably priced, seems like a better product than an EZ but 100.00 Cheaper?

 

My guess is exchange rate with the British pound?

MikeyB

 

the VA has a relatively small peak-to-peak HP gain on the dyno. Only 30 HP higher total peak output over stock 600/325 (A 555/305 would probably do better). The low end torque is reasonable (135 ft. lbs) which represents about about a 30% harder pull in the most driven region. But only 10-15% harder pull at the top end.

check this out for more detail on how I interpret the numbers.

Another point to be made about the VA is this: with small gains at the top end, this guy's fuel pressure is probably lower than the rest of the pressure boxes. The strength of the VA in my opinion is probably low end performance, drivability and how the power "comes in"

 

The reason they did the power curves the way they did was to control EGT and
pressures.
The biggest gains are right where you need them, 2000-2100 rpm where most of
you tow.
The engines are able to burn a lot of fuel in that rpm range without running into EGT issues but as RPM rises you have to taper back the fuel increase to control EGT.

 

Are you sure I can hide it from my dealer or not lose my tranny warranty? I know it is a risk but I am very easy on how I handle my truck, I am after a bit better performance, Better mileage and don't plan on roasting the tires everywhere I go so if the trans fails I want it to be covered. Does this make sense? I am really close to buying one of these boxes but should do exhaust and guages first.

 

what I thought, Ted. towing performance versus dyno day performance. can you tell us what the max rail pressure is?

 

How much do these boxes cost? I would also be interested to see what the max pressure this box produces compared to the EZ on say level 3 or 4. Does anyone know what pressure either of these 2 boxes is?

 

I've been running the Van Aken box for 3 years. Definantly noticed the power increase when I put it on and now I'm use to it. No problems at all and a very easy install.

 

I am impressed with van Aaken, I had a van Aaken on my last truck (2001 HO). Thanks Ted Jannetty for providing the info and dyno runs.

Guys like Ted is pointing out, this box may not add a ton of HP at the peak of the stock curve but it looks to fatten up the "area under the curve" so to speak, the lower RPM where power isn't so strong to begin with. This is power you can feel, power that comes on quickly when you mash on it, power you don't have to wait for until RPM builds up (like I do on my Bully Dog box).

Now for the real question to vA: How much does the vA raise fuel rail pressure? It says "within factory parameters" but that doesn't say a whole lot. The OEM system really doesn't spend much time at its max 23000 PSI, so the question is whether the vA goes above 23K, or if it maxes out there but spends more time at higher fuel pressures than stock.

Yes it makes you wonder why the vA costs less than the Edge, but from what I'm reading here van Aaken has their act together.

Ted remember when the original vA came out for the 24-valve several years ago and it was THE box to have? And you put together that big group purchase?

Vaughn

 

We've goofed around with the factory turbo a bit on the 03 and 04s, and found that they seem to fall off their map by around 34 PSI of boost with the factory airbox or an open element filter. With ram air, and speeds over 30 mph, the map is extended to about 38 PSI.

Rod

 

vaughn -- agreed. There is something about the way both VA and Ted communicate that is so refreshing I have to give kudos. I've been in email correspondance with VA and they validate everything Ted has said. I still don't know the answer to the pressure question, but I'd like to know how successful they have been at the drivability performance goal -- they use rpm, throttle position AND boost, and insert error into to fuel pressure feedback loop as a function of those three variables. So the've got to have very nice control over when the power comes in. definately not just another me-too pressure box.

I need dyno numbers for a 305. the 600/325 posted gains of about 135 ft. lbs +/- 8% from 1800-2500 rpm.

 

Hello Vaughn,

I think you answered your own question about fuel rail pressure.
If the factory maximum is 23,000 psi it is not going above that.

If we map the fuel rail pressure while driving you would see that it is varying constantly with throttle and load.

So a simple way to increase power in mid range is to raise pressure a little to gain torque where you want it and it doesn't take much either.

About pricing, I basically set the pricing to compete with the market, we cut our margins substantially to do so.

We like edge products and carry them but we feel that Van Aaken is a great product that has not been given a fair shake in the market due to pricing wars.

One of the things that made Edge so popular was price if you look back in Diesel history.

Just a guess here because it varies daily but the exchange rate is somewhere around 1.81 US dollars to 1 British pound.

Not in our favor if you know what I mean.