Turbocharging my F355 - Or how to remove any market value from your F355 remaining.

No, I am listening to everyone... and seriously so. I think that everyone is bringing up good points, I may yet just change the wastegates out for a number of reasons without actually using the ones I have... although, I confess, I will probably try them based on my research of them (they have reportedly been pretty solid from this particular company).

I see this turbo as the starting point for me to decide on a final turbo spec... It's just a starting point, not the end point. I do intend to switch to a ball bearing turbo later on and I do intend to run better wastegates. Nothing would be worse that buying name brand wastegates that are too small for the job and a fancy ball bearing turbo that is too big, only to have to spend top dollar again to see if I am going in the right direction. I have a fair amount of experience, but still, I want to see where I end up at with this and dial it in from there. I can afford to throw away a 200 dollar turbo and a pair of $100 wastegates.

You'll notice that I didn't dick around with the engine management, I could have gone with a much simpler ECU, settled for batch fire, no CAN bus interface, wasted spark, etc. I didn't even need to get a dual wide band unit or individual cylinder EGT probes. That is the stuff that I am really sure about and like I said, I am not even messing around with lower spec components as they are not going to change.

 

I didn't see anything about how they were made. There are some critical things to observe with regard to these ebay turbos:

First, most of the manufacturing related failures are due to one of two things:
A. poor assembly quality control - actually taking the time to measure clearances etc.
B. improper balancing - poor balance and high rpm = death of turbo

While materials are a potential concern, the Chinese have demonstrated that they know how to forge high quality metals and are not complete idiots with regard to metallurgy.

Secondly, many assume that the turbocharger is too blame, but often times it's not. People tend to run their turbine inlet temps way too hot and act surprised when that kills the turbocharger. The reason that high dollar turbos don't fail under similar circumstance are due to the fact that they use premium quality bearings and metals (that you pay for) to prevent such destruction from taking place.

A great example of this is Tial's knockoff MVS wastegate fail where they are running the wastegate over 2k degrees Fahrenheit. The Tial lives and the knockoff dies in about an hour. Newsflash, if you are running turbine inlet temps of 2,000 degrees F., you are doing it wrong. The wastegate is the least of your concern. Turbine inlet temps should be much, much lower, like 1650-1700 degrees F max. The max I ever ran was on a Nissan GTP motor with all inconel happiness everywhere and that was 1850 degrees F. I guarantee you that people are over spinning and over heating these units and then acting surprised when they fail. How many people have temperature data for these failed units or have actually analyzed the reason for failure of the unit? I haven't seen any... nope, just blame it on being junk.

I'll get off my soapbox.

 

I know what you are talking about, and once again, like I said you have to inspect these things, because pot metal, epoxied compressor housings, and other such non-sense are inexcusable. I would be very pissed to have received one of those units.

The turbonetics article is a great factual examination of the common problems with the turbos, and short of doing my own materials analysis, I have to look at the evidence with regard to the actual unit I have.

So, I will disassemble it to show you what I have and identify any concerns that I share. I think that you are making a valid point regarding the turbo quality. I am planning on running a low pressure ratio, so I am going to be spinning the turbo far below the max RPM expected.

Overall, and feel free to examine the pictures I took, I am reasonably pleased with the "junk" I received. There was a few shavings in the exhaust housing that I did catch and remove, but otherwise, this turbo looks reasonably well assembled. Did they balance it as elegantly (and accurately) as some companies, I am sure that they didn't, will it matter at the RPM's that I plan on spinning this turbo at, probably not.

https://www.dropbox.com/l/sh/Czb3KAfPehq3PBaMKjSGHu

The pictures above are in reasonably high resolution. The turbine housing casting appears to be of as good quality as anything else I have seen come from Garrett or the other big names. The compressor housing and all the associated parts appear to be of equally adequate quality. The center section appears free of contaminants and no obvious play can be felt in the bearings (axially or otherwise). I think I did ok... tell me what I missed in the photos.

Mark

 

Here is some love for all the single turbocharger haters. I know that you all aren't hating on it seriously.

When I saw this gem, I was pretty much sold on considering the twin scroll single GT45R on eBay. It was just too easy to not try. Basically, it's close in spec to a Garrett GT4094R (a $1500+ dollar turbo). Strangely enough, one of the recommended units using Garrett's android app. I don't even want to say what they estimate for 10psi of boost. A little more research suggests that spool will likely occur somewhere around 4200 RPM.

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I have a little bit of porting to do on the turbine inlet.

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Thanks!

 

It's all fun and games until someone gets their eyes poked out... Very excited about how it is all coming together. Image Unavailable, Please Login

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Yes, AEM CDI, I am on the fence about using it. I have other options, I am still playing with the options. I really want to go COP with the ignition.

I would pryyml


Sent from my SM-G920P Tapatalk. I am sure that I will make it work.

 

That is the best piece of advice yet... Keep it simple and keep it safe! I disagree that speed density is superior to mass air flow, but it is easy enough to tune and accurate enough for an acceptable outcome. Dual vs single turbo is moot when it comes to spool, the size of the turbos, (whether one or two) determines the spool. There is no reason a twin turbo would out perform a single twin scroll turbo... NONE. Elaborating on that point... imagine two motors spinning one large fan versus two motors spinning two medium size fans.... which one will move more air for a given horsepower assuming that the fan blades are equally efficient and that the energy to drive the each of smaller fans for a given air flow is 50% of what it takes to drive the one larger fan? Fact is that there are less losses (likely) in spinning one fan versus two. A twin scroll turbo is essentially two motors spinning one fan, and a twin setup is two motors spinning two fans independently.

I could be wrong, I'm not an engineer or a car guy remember.... Although, I suspect that those cars carrying my family name have won more races than most anyone else I have seen posting on this forum (my apologies to anyone with the name Ford... you have me beat!)

Simple is exactly what I am doing. This system is dead simple and I am planning to use E85 just because I don't know that motor all that well. Thus providing me some safety margin... I know I can run 10 PSI on the stock motor with premium, but for development work E85 is just dead simple... I can easily transition to premium unleaded on down the road.

11:1 is pushing sensibilities (not sure I am going that high yet) but I can reduce dynamic compression by altering cam timing with little effort... so that's another option and I might just do that. I am guessing that dynamic compression will be (under boost) around 17:1, which is what I used to see all the time with my Miata motors... and they never blew up.

Yes, I had to pull timing and, yes, they had to be well tuned, but they went like stink and had no problems making 300+ HP at the wheels despite the low pressure ratios. For what they were, Miata's, they went like stink.

 

Those are so cute... I see a street race in the future.

 

I was doing the exhaust calculations tonight, I might be a tad bit undersized on the exhaust. I am going from the 3.5" turbine exhaust into a 3.5" muffler inlet, which splits into (2) 2.5" outlets and terminates at a 3.0" exhaust tip. Prior to the turbo, I am running (2) 38mm waste gates each of which will run unimpeded to a 2.5" tip. Running the wastegates to atmosphere sounds gnarly.

Yes, it is a low cost system compared to what a proper system would cost. Don't try this at home kids, we all know that it is not going to work.

I hope that this is a lesson of what not to do.

My best guess is that this system is capable of a max 600 HP.

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Further lowering the value of the car... lol, and I am sure to make Enzo himself roll over in his grave, I have decided to use the AEM CD2I ignition configured for waste spark and I am going to ditch the factory coils and spark plug wires in favor of some Denso COP sticks.

So, bye bye to spark plug wires...

8 Coils $40
8 connectors $30
AEM CD2I model 2801 - I forget what I paid for it... it's been lying around for years (say $300)

So the ignition system is $400.

 

Well that is an interesting point that I had not considered, however the gas flow is 1/2 the rate... so is the polar moment of inertia really twice as large (or greater) for the single turbine? The answer is significantly so...

Assuming that the both wheels are made of the same material and weigh roughly the same at a given radius, the moment of inertia appears 60% higher for a 87mm turbine compared to two 59mm turbines. Thanks for pointing that out.