I started a new thread here as a place where some posts can be answered and openly discussed. When posts are made in specific vendor sections, we do not respond in that specific vendor thread as other vendors do not respond in our specific threads. It is kinda an unwritten rule, but generally frowned upon for vendors to post in other vendors sections. So hopefully, this is a nice middle ground where there can be an open discussion about topics that may pop up in those threads.
There is a new turbo thread by ZZP that had a post that tagged me and I would like to pass some more information along about the post I was tagged on and another one, here are the 2 posts by @MrGrey and @SSREAPER
- you think supercharge is safer than turbo? i know a few people who has blown their engines from running supercharge or turbo.
you’re still forcing air to the engine.. keep that in mind.. it’s kinda like choosing between smoking cigarettes vs smoking e-cigarettes.
both will kill you in the long run..
- @MiM @MrGrey
I am by no means a forced induction expert but in my opinion ...Super chargers are indeed safer than a turbo for people who dont know how they work. The superchargers air induction is in direct alignment with engine rpm...the numbers are repeatable. At a specific RPM you have a specific amount of air being induced. The only way it changes is if you change the pulley on the supercharger. When the kit is designed, it is designed with the safety limits of the engine taken into consideration. There is no need for gauges although having them just to keep an eye on things is a great idea.
Turbos rely on the exhaust to spool it and drive it and that alone introduces variables. Being able to have a controller to change boost levels introduces another set of variables. Variables on top of variables on top of variables creates a situation where one thing goes out of whack and the whole equations goes to hell. If you like to fiddle and know what your doing... turbos are great
That to me is a factor to turbo or to supercharge.
Now 2 things... 1:If I am wrong then @Dave@DDMWorks who is considered to be the master of BOTH systems please educate me.
2: Nowhere did I say one was better than another so dont go there!!
Our supercharger kit has had a fantastic reliability record, even with the vast majority of those installed on completely stock engines. There is only one engine that we know of that has had an issue with our kit, however it was not on our base kit that we have for sale and was running higher boost pressures. As far as we know, no one with one of our base kits has blown an engine. We know of some other supercharger kits that have had engines that have failed though and over 50 turbo engines that have failed. We honestly lost track of the number of blown turbo engines after we got to 50, and while typing this actually just talked to another one. Based on the number of sales of all forced induction kits the turbo kits have had the highest percentage and the highest number of actual failures though. There are several reasons that these turbo kits could cause an engine failure along with how the slingshot is driven. Some of the design choices in these past turbo kits could have been better and some quality control issues caused most of the failures we have seen.
As for which is safer for the stock engine, supercharger or turbo, at this point our supercharger kit has definitely proven to be safest option for the Slingshot to date. We have put a lot of testing and development into our turbo kits coming out and ZZP has a lot of experience with the Ecotec also, so going forward the newer turbo kits just showing up should be a lot more reliable than those of the past.
That being said, an engine that is designed for forced induction can be safe just as safe with either the supercharger or the turbo, if that engine was designed for it. A naturally aspirated engine though, like what is found in the Slingshot, that has boost added to it does present a little more of a challenge to do safely. Most all of the failures we have seen of engines from the turbo kits involved 1 of 2 failure mechanisms.
To understand those failures a little more, lets look at the pistons on the LE5/LE9 engines, which were designed as a naturally aspirated piston. When OEM's design a piston for naturally aspirated, that piston is designed differently than a forced induction piston typically. The naturally aspirated piston has an upper compression ring that is kept relatively close to the top of the piston, also the ring gap is typically kept tighter to allow the combustion pressures be as efficient as possible. The downside to this design is that when you start adding more air into the engine by forced induction, the cylinder pressures and temperatures start to rise. Since these naturally aspirated pistons are not designed for that, as the temperature and pressure rise, the heat gets into the piston and starts to affect it. One thing that can happen is the upper compression ring is heated, that upper compression ring starts to expand and eventually with enough heat, the ring gap can completely close down. Once the ends of the ring can no longer expand, the ring will keep trying to expand and push harder against the cylinder wall and also push on the top of the piston. In most of the failures we have seen, this force causes the piston to fail and a piece of the top of the piston comes off and starts to destroy the cylinder. Typically this happens on cylinder 2 or 3 since those are also the cylinders that run the hottest in a stock LE5/LE9. Occasionally it would happen on cylinder #1 since that is the last cylinder to get coolant, rarely on cylinder #4 since it runs the coolest.
That being said, heat build up causing piston failure is by far the biggest reason for engine failures that we have seen on the Slingshot. A turbo installed on the Slingshot becomes an exhaust restriction in the system and backs more heat and pressure back into the engine than the supercharger setups. Depending on the turbo being used, turbine A/R and the exhaust manifold design, the exhaust manifold between the engine and turbo will see around 1.5 to 2 times the pressure seen in the intake manifold with a turbo setup. On the supercharger setup, since the exhaust is basically wide open, exhaust pressure is more similar to stock, depending on exhaust design and engine RPM. That big difference in pressures between those 2 setups is one of the reasons that the supercharger has been safer on the stock LE5/LE9 engine. Without all of the backpressure, the heat can flow out of the supercharged engine easier. That being said, other issues like mismatched fuel injectors is something that we take care of by making sure that all of our fuel injectors are flow matched to within 1% flow rate. I do not believe that ZZP is including fuel injectors with their kit, so being dependent on the stock fuel injectors they should be good there also. The HAHN kits used to ship with non flow matched injectors, but I am not sure on the current batch if they are matched or not. Some of the Alpha kits had issues with MAP sensors coming out under boost, which also affected the fueling and would cause engines to be destroyed. Our kits ship with a MAP clip to ensure the MAP sensor does not come out and once again, I believe the ZZP kit uses the stock MAP sensor which locks securely in place also.
So, as of now, I would say that the supercharger kit has been the most reliable for several reasons. With the new turbo kits coming out though, I would expect that the newer turbo kits will also prove to be just as reliable at lower boost pressures and below 300hp/torque. Of course, when supercharging or turbocharging a stock engine you always run the risk of damage to the engine and should take that into consideration before making that decision.
Hope that helps,