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do88 Intercooler upgrade and Dyno video

If you keep the turbo the same and all the other variables (except for the 1 intercooler, which is what you are trying to validate) ... then boost is boost... or am I missing something?
so if we kept everything else the same and only swapped the intercooler (which we did), then what part of the result is unclear, exactly?

I mean I can explain it for you, but I can't understand it for you.
 
Having done similar tests to this before, and posting about them on the forum, I am taking some liberties with ya'll, mostly because I'm not a big fan of going over the same stuff time and again. However, this is a new thread, so let's dive in.

First of all, this strange notion that boost is boost, so like whatever man.. or it's close but equally mentally challenged friend "the only difference is the Detla Tee man (that's change in temperature for the layfolk)" is feeble-minded garbage. Were these two things true, one could simply put a 13c on an Ls1, crank the boost to the moon, and run a big intercooler to have all the horsepers without any of the lag of the 78mm's that are so ubiquitous in that crowd.

To understand what's going on here, you have to first of all ignore Ben's dumbass because he's simply arguing for the sake of argument. You tell him to go eat a box of crayons and work on his 850 :-P

Now that we've done that, to understand what's at work here, and why people do some of the things they do as it relates to turbo chargers. If boost is not boost, and 10psi from a 13c is not the same as 10psi from a 15g is not the same as 10psi from an hx52, one needs to also consider why 10psi with that hx52 is not the same on an 8v as it is on a 16v, and similarly, why it would be different on a 2jz or the like as well... There's different operating characteristics at play here. the 8v moves air like a garden hose moves water, the 16v is more along the lines of a fire hydrant, and the 2j (or ls1 or whatever bigger engine) is more like two hydrants (conceptually).
now just off hand you can imagine what each of those is going to be doing at say, 10psi of water pressure.. in terms of the volume of water getting moved. With this in mind consider then how air (Which behaves a lot like water in the paths it takes) moves through the engine, and what's required to create boost (which is, as many ignoramuses like to point out, a measure of restriction-but not the way they usually mean it). You have to have a surplus of air after the compressor outlet and before the exit of the system (the end of the exhaust). that surplus usually comes about from a combination of things: your charge piping, intercooler (if you have one), the engine itself (and it's ancillaries like intake, throttle body, cam, etc), the exhaust manifold, the turbine housing, the turbine wheel, and the rest of the exhaust.
With tiny turbos like 13c's (and to a slightly lesser extent a 15g) the choke point may very well be the turbo itself, and at elevated levels of boost this is borne out when compared with other turbos.. a 15g at 7psi may only make a couple more horsepower than a 13c at 7psi, as the boost goes up, that disparity will grow until they both hit their respective choke points, which is to say, all other things being equal, the restriction in the turbine housing/wheel combo will not allow it to spin any faster to move any more air. Usually you see this on a dyno by the powerband shifting around a little perhaps above a certain boost amount but the hp not changing much, and if you have the means to measure it, your pre-intercooler air temps will get very spicey very quickly. This is also why no amount of charge air cooling will let you continue to make more power.. you've simply reached the maximum the turbo will allow. Generally at this point the turbo will also have a very short and violent lifespan, and probably so too will the engine.
Bigger turbos move that choke point further out by increasing the volume of air that can pass through the turbine/housing, bigger compressor wheels don't have to spin quite as fast to move more air, and so on. This is also why a turbo that is too small for an engine can and will result in less power than it would make NA (think 13c on an ls1. now stop laughing). It may also not make any appreciable boost either at that point

So we've cover the turbo aspect of it, and hopefully have laid to rest why boost isn't boost. Now to keep it on topic with this thread, let's talk about the intercooler, and as it directly relates to this discussion, the wastegate and what purpose it serves, as well as how it works (because apparently some people don't get it. lol). So.. wastegate.. that's our turbo control device that prevents turbos from just running at their choke point 24/7, but how and why? so the how and why are easy, you apply boost pressure on top of the canister, and it opens a bypass flapper in the turbine housing to reduce the volume (And pressure) of air going across the turbine wheel. Some designs are better than others, few are better than external gates at actually putting a clamp on the fun, generally because you can vent a greater volume through an external gate. But I digress. The source (most often) for the wastegate is the compressor cover. This matters (in a minute), sort of.. but perhaps not for the reasons that immediately come to mind. Going back to the system as a whole is comprised of various choke points, an intercooler is nothing if not a big choke point, and truth be told, boost values will be higher without one (So too will be IAT's, and overall air density will be down, which is not good for power). Compressing air generates heat, reducing heat by it's very nature will reduce pressure (this where pv=nrt comes in to play, but you can't think about it as a static thing because it's not).. Great, lower iat's, but in order to do that, you have to have surface contact with the air to transfer that heat.. this imparts a restriction as well. So not only are you losing pressure due to heat rejection, you're losing pressure due to resistance-to-flow.

And that's where this should, for our astute readers, become clear: If you're sourcing the wastegate signal from the very front of the system (compressor cover), and you're measuring from the intake manifold (post intercooler piping and intercooler and throttle body), the two pressure values will not be the same. They'll never be the same. If you change something between those two points, you will see a change in boost pressure. If your intercooler is sufficiently bad, you may see a large difference (like, if you're using an ebay intercooler. don't do that. most of those $100 ebay units are absolute garbage). I had a turbo 6.0 this summer that with just the intercooler change went from like 290whp to 400ish hp, at roughly 4psi. The bad intercooler would only make an indicated ~1.5psi. Temps were no different. Wastegate source was the compressor cover.

When we tested the stock volvo intercooler against the ebay intercooler against my garret 950core, every single one produced the same intake air temps (plus or minus a couple degrees depending on how quickly back to back runs were made), but wildly different boost and hp numbers.. the ebay intercooler lost ~10whp to the stock volvo intercooler, and the stock volvo intercooler gave up 15 or 20 to the garrett intercooler. the spread in boost across the 3 was probably 3-4psi as well but I don't recall that off the top of my head.

TL;DERP: bigger intercooler flows more air and as such is less of a restriction at the current power levels, so map sensor reads higher boost pressure. It's basic fun physics. This is also why bigger turbos make more power (usually) at a given boost level. moving more air in and out. at some point the engine becomes the problem and you can either fix that, or increase the pressure. It's usually easier with a bigger turbo to do that, since you won't have to spin it a bunch faster to reach the higher pressure vs a smaller one. To see that at work, you would want to have a pressure reading in the exhaust pre-turbine.

Somewhat funfact: part of the problem with the ebay intercoolers is the exceptionally poor end tank design.
 
Having done similar tests to this before, and posting about them on the forum, I am taking some liberties with ya'll, mostly because I'm not a big fan of going over the same stuff time and again. However, this is a new thread, so let's dive in...
Thank you for that great explanation. The turbo is described as "an upgraded t3 turbo". In your experience, how much of a turbo and exhaust upgrade do you need to do to make the DO88 useful? T04E? 3" Ultimate wastegate? 3" downpipe?

Would this also explains why when I upgraded from 2.25" downpipe to a 3" full exhaust with 3" Ultimate wastegate why my boost went from ~12 psi to about ~14 psi with no other changes?
 
Thank you for that great explanation. The turbo is described as "an upgraded t3 turbo". In your experience, how much of a turbo and exhaust upgrade do you need to do to make the DO88 useful? T04E? 3" Ultimate wastegate? 3" downpipe?

Would this also explains why when I upgraded from 2.25" downpipe to a 3" full exhaust with 3" Ultimate wastegate why my boost went from ~12 psi to about ~14 psi with no other changes?
Try not to think about it in terms of turbo size and more about how much horsepower. I'm sure if we really tried we could push a little 13c to 200whp but it would be on the bleeding edge of everything "timing, AFR, air density". Its kinda like how boats and airplane engines are way over built because they have to operate at wide open throttle for prolonged periods of time where your normal daily driver rarely sees that much WOT time. We are trying optimize the operating window of this race car. All of the components affect each other. Its my opinion that around the 200whp area of an 8valve redblock the stock intercooler starts to become a significant restriction. I'm confident you could push 300whp out of the stock intercooler but it will likely cost in other areas.
 
Try not to think about it in terms of turbo size and more about how much horsepower. I'm sure if we really tried we could push a little 13c to 200whp but it would be on the bleeding edge of everything "timing, AFR, air density". Its kinda like how boats and airplane engines are way over built because they have to operate at wide open throttle for prolonged periods of time where your normal daily driver rarely sees that much WOT time. We are trying optimize the operating window of this race car. All of the components affect each other. Its my opinion that around the 200whp area of an 8valve redblock the stock intercooler starts to become a significant restriction. I'm confident you could push 300whp out of the stock intercooler but it will likely cost in other areas.
I am in the same boat as you. Dedicated racecar. WOT and high RPM much of the time. I want to get through 14.5 hours of racing and be competitive. I also race Lemons so if we could get over 2 hours out of a tank of gas, we could potentially skip a pit stop. I like the idea of a boost switch. So it sounds like at this point a better intercooler might give us a little bit better efficiency.
 
so if we kept everything else the same and only swapped the intercooler (which we did), then what part of the result is unclear, exactly?

I mean I can explain it for you, but I can't understand it for you.

The boost is increased at the manifold inlet due to less restriction because of the improved intercooler... This obviously makes more power because the motor is seeing more boost... The thing I would be interested in seeing is if you maintain the same inlet boost pressure as what the car made before, would there be a difference or what is that difference? I think that would be a better comparison, at least a more interesting one to me.

Sam has stated that the car never had a problem with intake temps getting hot and that the preexisting power level was sufficient to win races.

One of his goals was to reduce stress and make things more efficient. From my perspective, letting the car run with an increased boost pressure would increase fuel consumption and stress on components... being able to eliminate a pitstop for refueling can make up for a ton of lap time that you might gain from having more hp.

After talking to Sam, it became clear that it's not an easy test to do because, with the existing wastegate, there is no preload on the setup, so it would involve some hardware swaps instead of some easy adjustments.
 
Chumpcar and Luckydog only allow two hour stints. Randy also has a fuel cell. I can do 1:50 with a stock 16 gallon tank, probably more if I short shift, and I run more boost. I don't think they run Lemons, which doesn't care if you stay out on track all day.

Their functional capacity is only 18 gallons, though.

The 2-hour stint limit is a big factor.
 
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When we were racing we could go 2h45m on a stock 240 tank of fuel, and we intentionally tuned it that way in lieu of going for strictly power numbers. The additional 15 or 20 minutes a tank secured only needing 2 stops a day, not 3. We were never able to secure an overall, but damn we came close.

If you have the physical and mental stamina to pull off stints like that,,, its very powerful strategy to produce wins
 
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