customblackbird

iTrader: (2)

congrats on testing hundreds of motors.

how is the TB air/water tight? My stock and other LS TBs have a 5/32" drilled hole in them... seems like a big "air" leak to me. You would have to Cap the TB or just test from the pressure source (turbo compressor tubing start) and test the whole cold side and motor. Or cap both ends of the cold side and test, then test the motor side. I still feel that other variables can change what "checks" out in this test. What would be the differences between a hot and cold engine? Would the intake (2 peice or equivalent) be more likely to leak when hot or cold? Did you know that the TB shaft seal will NOT seal fully when its pressurized? The seal is designed to be sucked close against the shaft and doesnt seal well when pressure is introduced and thus most will get a slight boost leak around the TB shaft throttle cable side.

You would have to block both the valve cover PCV vent as well as the PCV valve (I have never seen one completely seal as they have such loose tolerances).

I'm not saying the test is invalid... but how far do you have to go to verify and intake doesnt leak. It used to be just spray starting fluid at gasket points or use propane. Personally I'm not comfortable pressurizing the crankcase as it should never see pressure and I would hate to push a seal our or create a leak that wasn't there. By not sealing the PCV and not pressurizing the crankcase I will have blowby/leak that will then require a visual leak testing method as you should hear the blow by. I can hear my blowby my cranking the motor over by hand. A compressor running or pushing air into something creates its own noise... i wouldnt be able to hear a "leak" more than likely I would need a visual source of identification.

"A boost leak raises compressor wheel speed, raises IAT, and increases exhaust gas backpressure." This is strickly turbo... has nothing to do with my supercharger. Also compressor wheel speed doesn't greatly affect IAT temps... compressing the the air is what causes the heat. If your not compressing the air then your not creating much heat, boost is a measure of restriction... less boost = less heat. I'm sure the physical impeller spinning faster prob has more to do with a turbo as your requiring more rpm/exhaust to produce the same boost and that relates to slightly more heat but in a supercharger application impeller wheel speed is directly related to crank speed via the pulleys. So bleeding boost just means you produce less boost in a supercharger application. Again your exhaust backpressure statement doesn't relate to a supercharger.

"In worst case situation it can blow the engine (high IAT) or turbo (over speed)" This is an alittle over zealous statement. You would have to have crazy IAT temps with no fail safes. Worst case is you loose boost and thus peformance directly related to the size of the boost leak. Every stock LS PCM has an IAT temp retard table. People with 1/2 a brain on a boosted motor will have some form of logging/viewing IAT temps and will be taking the appropriate measures to keep the engine out of the danger zone. A tiny intake leak will not cause a crazy amount of turbo over speed. A faulty BOV or WG will cause engine damage.

I'm sure this test is valid and has some uses but lets not make it personal. How many people perform this test when not many people know about it? Intakes are usually pretty fool proof, you bolt them down and go... LS motors make it even more easy with the new gaskets. Your saying its necessary doesn't mean it is, your reputation proceeds you btw and I'm aware of what you say has to be taken with a grain of salt. But I do feel this test has some validity and depending on time I might try to test this theory out. I have just sorta finished up a water/air intercooler setup and I'm probably going to test the cold side piping for leaks... I might just leave it all intact and pressurize the engine as well. Although I already know my stock intake isn't leaking.

But moving forward lets keep the thread focus on the dorman intake and peoples results relating to this intake.

kingtal0n

iTrader: (1)

I saw the hole in the LS throttle body. That is unusual among engines, I thought somebody had added that, but you are saying it is OEM. Remember this is my first LS motor so I am not sure what is original and not. Most engines have water/air tight TB. In any case, It still didn't make a difference. Just apply pressure and go.

If you find a leak, you fix the leak. If you can't fix it, you replace the part, or deem the leak insignificant. My TB didn't leak, maybe it will when I apply 15psi of pressure. Leaks are bad, and saying that a part is going to leak as an excuse to not go turbo? Is kind of silly.


There are many kinds of PCV valves. You can buy a nice high performance valve if you have a serious engine or require longevity/reliability the way I do from mine. There are other choices besides OEM; I will never use a leaking PCV valve because of the dangers it presents to the engine. It might take several tries to find one that doesn't leak if you are attempting to use cheap PCV valves.


Those tests do not apply pressure to the sealing points. They will not reveal weakness at high pressure. Same with smoke test- useless in forced induction without the aspect of pressure to simulate boost. If the engine can't handle 15psi when it isn't even running then how is it going to handle it when it is? You are doing ONE pressure test with the engine off first, and from then on you intend to apply it from a turbo for the next 100,000 miles over the course of 10 years. In other words, if you don't do that one test, your engine is still going to be tested the next time you run the car, whether you like it or not.

You fill the plumbing and then check for leaks. The plumbing holds pressure. You don't need to keep filling it, or running the air compressor. Remember the engine is going to pressurize itself anyways once you run the car, if you are forced inducted, so you are only preparing it properly. This test is about awareness, preparedness. It is absolutely essential. To skip this test is guaranteed going to cost you horsepower, and it could cost longevity of parts.


In a supercharger application there will be a performance loss for each air molecule which is leaked. There may be less risk than when using a turbo, yet the point remains that we pay alot of money for those parts, and if there is a leak it affects performance. Big enough leak and you are right back to naturally aspirated, so the size of the leak is more or less proportional to the effective percentage of performance you are extracting from the expensive part.

You tune a hundred cars and eventually you find one where the owner refuses to pressure test and has an incident with broken pistons after signing a disclaimer. It is statistically relevant. A 20 minute test saves engine, improves performance, non negotiable IMO.


Awareness is always an issue. How many people were aware that cigarettes caused cancer in 1950? Or that 2 meters of DNA is packed into each of your over 1 trillion cells in the human body? These things catch on, or not, depends on the results, what you gain or lose. There is no question that leaking plumbing reduces performance, and no question that is has a negative influence on longevity in turbo setups, and no question that the engine is going to "pressure test itself" again and again for the life of the engine. You put those things together and... I want to see it with the engine off at least once before I try doing it with the engine on for the next ten years. I build and tune for reliability and this is an essential step, just like using a paper air filter.

chris99gmc

So much for sticking to the OP...

Anybody have any numbers on this intake yet???

truckdoug

iTrader: (25)

realistically, those of us spending $250 on an intake are probably not gonna have it flow tested. my comparison isn't really a fair one since I cammed and increased compression at the same time as the intake swap. but there's more blabbing about it here:


https://ls1tech.com/forums/generatio...3x-intake.html

customblackbird

iTrader: (2)

Haha this is what kingtalon is known for. I've read about him on this forum before and I most ignore him.

I'm interested in numbers but like truckdoug said I won't be shelling out the cash for a Dyno session. I would have no issues sharing logs that give you all the data you need to calculate performance.

I'm honestly surprised that some of the popular car mags haven't jumped on something like this. They tested factory intakes vs aftermarket but no stock replacement aftermarkets.

xEtherealx

They make their money by pimping for manufacturers that will pay for ad space, I almost never see best-value pieces being reviewed by magazines.

tech@WS6store

iTrader: (2)

Their "budget builds" are like 4k+++
Most mags now days are out of touc with what is going on. Idk if Justin at gmhtp is on here anymore or not.

Stampede4ever

Anyone have back to back dyno test yet?

Thanks.

foxsl

iTrader: (1)

Unfortunately the few posts I could find on this intake scared me away from trying it as they complained about symptoms which could very well have been related to the install and other aspects of their setup. I went on to a tbss/nnbs intake manifold instead however these Dorman truck intakes do still look like they have potential for high rpm fun

G Atsma

You did well going with the tbss/nnbs manifold. But yeah, Dorman is doing some interesting stuff with their replacement manifolds. Using old FAST tooling sure can't hurt...

omc8

iTrader: (7)

Please update, did you reinstall the Dorman and solve
your tuning issue that you were having ?

foxsl

iTrader: (1)

Thanks, it's ported too, now I just need to ditch my 1 3/4" mid length headers to take advantage of the intake combo

customblackbird

iTrader: (2)

Nope, basically it’s sitting on the shelf. I’m thinking about using it on another project that will use the same supercharger that was run with this intake even if it was just idle.

But I did want to clarify that the Forman was not leaking apparently. My vacuum is just poor with this custom cam. I was told 16-19” and I’m pulling 13-14.5”. I swapped it out for a GM stocker old style truck intake. My vacuum went unchanged. So apparently the dorman wasn’t leaking and wasn’t at fault, but didn’t really have a tuning issue... it was just low vacuum. I got the idle AFR squared away but I had some surge etc which was caused by the custom cam and ported stock TB which I had to mess with the idle airflow tables... still never got that at 100% but I yanked my plugs and they all looked amazing.

I’ve just swapped a NNBS intake onto this same motor and going turbo 12+psi so I didn’t want to put the dorman on with the higher boost pressures. I will leave it for something that will max out around 9psi.

omc8

iTrader: (7)

Ok thanks for clearing that up .

megabuddys

If anyone cares, I have been running the Dorman intake almost a year, 800 + miles, I don't know yet if its quicker by feel, but with a poor launch it still ran out the same MPH on top. Hard to tell. I don't think it could make less power, I pulled the plugs and they look better/ more consistent than they ever did with the Stock truck intake. I run 21.5 lbs normally. No vac leaks, nothing. My setup has a less than ideal size Intercooler and even with higher Intake temps, no issues..
I did not split the intake. I smoothed the ramps in the runner down like was mentioned, and I put large fender washers under the main bolts holding the intake down, some requiring shaping to fit. I was hoping it would distribute the clamping load. I have changed my combo through the years and would not be able to re- dyno it to see an accurate comparison. I do plan on pushing it higher boost, probably next year.

customblackbird

iTrader: (2)

you've been running 21.5psi through the unopened dorman truck manifold? Sweet! It was flowed and flowed as much as the TBSS intake but it was dynod by richard holdstender and it performed worse than the stock 3bolt truck intake.

wannafbody

iTrader: (2)

21.5# of boost is impressive.

G Atsma

Do you mean Richard HOLDENER?

omc8

iTrader: (7)

I know Richard Holdener tested a DLS2 , but was not aware of any dyno test he did on a Dorman Truck 615-183 ....... could you post a link of that test.

customblackbird

iTrader: (2)

yup that guy. He posted dyno results on the sloppy FB page. Idk what it was run on (not a stock 5.3 with 450hp)... but it made less than an LS6 which means it makes less than the TBSS or NNBS truck intakes.