I've run T6 turbos on a few small cid low na hp engines with very good results. I think the whole debate is over thought. I'm not into high dollar turbos for my low dollar stuff so if its 200+ na hp I'm looking at T6 stuff as well as reasonably priced T4's.

 

Heres a good example of what I was talking about. Typical 5.3 at 30lbs with an 80mm T6 VS a 98mm T6 on the match bot. You can see on the 98mm compressor map it's in its happy zone. Something like an S475 would likely be off the map.

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I agree that the 475 isn't in a good place, but I'm not in agreement with those maps. That plot is roughly good for 1400-1500hp worth of air with a good cooler. I don't see any stock headed 5.3 making that power. Am I wrong? What did you plot those on?

 

Also, many run near the right edge of the map, and still make decent hp with charge cooling and less than a max effort build. Imo, a small turbine is much more of a hp killer than an undersized compressor.

 

How does this look at 25 or 26lbs?

I'm very curious of the HP ratings of each of those graphs as well, but I'm unclear on how to exptraolate a good guess that might be remotely accurate?


I spent a bunch of time with Matchbot several years ago during a 414ci build. According to MB I needed an S500 turbo to be ideal. And after pricing them I threw in the towel and bought a VS S480. I'm sure it's undersized on that motor, but it's pretty much the fastest street car I've ever driven upto 120 mph and 6500rpm's. I can only imagine what it would do with something like a GT55. On the street it would be just about useless considering that the S480 on that motor will smoke a set of tires at 75mph, 4k rpm's and 18psi.

 

I could be way off on this, but a VE calculator puts a 350 fwhp 5.3 at roughly 80%. Enter those numbers into matchbot, and it fits on the 76mm map at 30 psi. https://www.borgwarner.com/go/R4YOWI #ad

 

What the turbo will do VS being in it's highest efficiency range are two totally different things. Most aren't going to sacrifice low end performance and response for a turbo that will run in the highest efficiency island. This is why guys that switch over from something like an S480 to a GTX 98 mm make more power across the board without power falling off at greater boost numbers. Yes, the record setting SBE guys with the singles run the big GT55 based units. And yes they are making damned near 1400 crank hp going by weight and trap speeds.

Yes a tricked S485 with race cover will amke 1200whp. But it is working hard to do it. Its no longer making the same power per pound it did in the 10-15lbs of boost range. Slap on a GT55 98 and it will continue making the same power gains from 15 -30+lbs without working up a sweat or heating the charge much.

Those maps are off the garret turbo advisor.

Plug the 5.3 into the match bot even. If you leave their suggested boost of 10-17psi the S480 is still on the edge of the map. Plug in 30 and it's off the map. And that's only going to 7k on gas. Add 7800+ and e85...

Now plug in the S500 94mm and the plots are back in the happy spot on the map.

Below are the 5.3 plots on an S480 at 17 and 30lbs. Its why the SBE guys are running 107mm GT55 china copies and kick'n butt!

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Now look at the S500 at 30lbs...
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I'm not arguing that it won't make more hp in the center of the map, that's pretty much a given, but it does come with trade offs. I guess my point was that there are multiple turbos that will make 30 psi on a stock 5.3 for guys with differing goals. Running peak hp in the center of the map really increases the chances of surge, and requires boost to come in very late. My other point was that Matchbot is only as good as the info entered, and by leaving most of the basic engine info as defaults, it's not accurate.

 

Point I was getting at is the 7000 plot is off the map for an S480 at only 17lbs. E85 moves the plots even farther to the right as well.(I used gas on those charts above) So for a drag car, the S475 is undersized for a max effort 5.3 IMO.

I agree the matchbot is far from perfect. But it gives you a good idea. Just depends what your using the car for. Most guys running 30lbs or more on the big turbos stall past the points on the map that would surge.

The On3 94 and 107 are finally getting some use. This guy made 1154whp at 27lbs with the $850 cast 107/103. Its a super basic cam only 5.3. Untouched 799 heads. Guessing the turbo is far from out of steam there. 27lbs sounds like alot, but that engine isn't making much power NA. That's a heavy car and its gone low 5's in the 1/8th.

 

Yep, I think we're in agreement, but we're looking at it from different perspectives. If your na hp is off in matchbot, every plot will be skewed. A few percent of VE makes a huge change at boost. My plots were on E. Basically boils down to a max effort can benefit from the 94+mm, but for a street strip guy wanting to flirt with 30 psi at the track, and turn it down, a 76, or 80 will get the job done if okay with the compromise.

 

Here's the plots from above. Its a 5.3 making 350 fwhp na (pretty typical for a stock headed, small cam, stock manifolds) with a billet S476 30 psi on E85. #ad

 

I just don't see it. I've been there tuning multiple cars. They stop making the usual gains around 20-25lbs. After that, the gains are very poor in the higher boost range.

Similar to adding timing and watching a dyno... When you stop seeing the usual large gains per degree of timing, quit. Same with boost IMO. You're just going to torch something pushing it. On a nice 6.0 the S475 won't even hold 20lbs to 7k. Boost falls to 17ish by then. They just can't keep up. Especially not at 30lbs.

If you watch/believe Richard Holdner, a typical cam only 5.3 is making closer to 400+. The reason I purchased my cam is because it put up 473 HP on a cam only 5.3 with a factory intake. Sure thats with long tubes, no accessories etc... and won't put that kind of power down through a factory manifold in the car. But I think a 5.3 with a cam on e85 typically makes more than 350 crank.

I'm not sure what you changed, but my plot doesn't look look like that for an S476.

Also if you're pushing 30lbs you really should be taking the engine much higher than 7k IMO. You're going to bend rods and break Ringland's running boost that high when the rpm drops on the shift.

My plots look nothing like yours at 30 lbs. They go completely off the map. If you zero out the boost and throw 98% VE in there you come up with this. Which seems pretty accurate for a mild cam 5.3 at 7k IMO.

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Here is my S476 map with the power numbers above.

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These also assume a 92% effective IC which seems ridiculous. I believe most A2A are around 70% at best. Which shifts everything radically to the left.

 

I played with the VE numbers. I found on multiple forums that a cam only lm7 would typically make 350 so that's the number I used. A 5.3 at 7k 98% VE is roughly 455 hp, that seems high to me for the engine in question, but I don't have the dyno experience to dispute it. If they do actually make a real 400hp then my numbers are off. We didn't talk about charge cooling, but assume at that point an A/ice water would be in place. After looking at maps, the 475 compressor is lacking, and the billet 76 is a pretty big improvement. Whether we agree or not, it's all good info.

 

I agree, and I am just guessing as well. I'm far from any sort of expert. I haven't gotten to fine tune the Matchbot much. Looking it more in depth like this helped me as well, I appreciate that! The Cam only 5.3's are pretty darn healthy from what I've seen.



This is the most power I've seen a "cam only" 5.3 make. So this is the cam I am running on my new twin 78/75 5.3 build. If it truly even close to those numbers it should make over 30hp per pound of boost. I'm amazed a "cam only" factory motor is making almost 1.5 hp per cubic inch. VE would have to be pretty decent I'd think! Also there's no mention of the heads on that motor. Not sure if it's the 706 or 799. The smaller CC heads may make even more power.

Most are dyno'd in a similar fashion with long tubes and no accessories so of course the numbers are a bit skewed compared to real world.

 

Almost 100hp in just a cam change, that's impressive. Sucks that there's not more info. I would assume that since it has a TBSS style intake that it has some 799, or 243 heads, but I guess you never know.

 

475 hp is roughly 110% VE.

 

If you zero out the boost and IC eff. on match bot it states 498 would be 110 VE. 105 VE for 475 @ 7k. Not sure how accurate that is (or if I zeroed everything that needed zeroed) but its how I was guessing at the plots. I adjusted VE to hit the number I guessed it would make on motor. Then went back and added boost.

 

I used an online calculator, which is pretty simple so I don't know how accurate it is either, but it's a ve calculator

 

I don't buy those camshaft numbers. 50-70hp is a monster jump, but 100 is unheard of. I'd have to see the dyno tests or have someone there that I trust. I have an aquaintance with a chassis dyno that does a shit ton of cam and header swap on everything from LS1's to LS6's. The best he's done is 110hp with a Tick Performance.

Aside from that, it sounds super nasty on their website. Doesn't sound like a cruiser at 2000-2500rpm's lol.

 

Holdner tested a similar cam the COMP Cams 54-454-11. Pretty similar results. This is on a completely different JY 5.3 and dyno than Texas speed.

This was the cam I had planned to run before I saw the MS3 results. A new MS3 cam also popped up local for $280. So I jumped on it.

The COMP CAMS 54-469-11 is the big brother to the above and made 7 more peak HP than the 454-11 cam above on a 5.3.

Then you have the FTI LSX StreetSweeper cam that basically makes within 4 HP of the above. All cams tested on different engine dynos and all putting out similar numbers. Though back to back track tests show this cam to be superior to the MS3 in ET/trap. But is $499!

So who knows! they all seem pretty similar in power production.

http://www.cpgnation.com/the-100-horsepower-upgrade/



You'll see though Holdners stock 5.3's with factory cams are making 360 crank HP. Which he claims is due to them being run with no accessories, no airbox, and open long tubes, bigger TB etc... Them optimized with the Holley ECU over the factory tune. I believe they are making these numbers but as mentioned once you get the motor in a car with accessories, factory manifolds, etc the numbers will drop quite a bit.