Can you turn the boost down below 7 lbs on a Hellion Twin Turbo kit?

[Junkyard Dog]

The question is in the title.

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[Junkyard Dog]

All of my searching on the internet reveals only information about how to turn the boost up, more boost, more power! Which is great and all, but I want to know, can I turn the boost down?

The answer is yes, but how far?

Can I, without too much effort, max out at 3, 4, or 5 pounds of boost?

Then turn it up to 8 or 9 or 10 when I want to do that?

What is the low end on the boost?

I do not have a full grasp yet of turbo systems. I know that they have a boost controller, which adjusts the boost level, but there is a minimum controlled by a spring in the wastegate? The controller only raises the boost above that spring level. For example, if that spring is 7 pounds, then that is the lowest the boost can be. Does that all sound about right?

If so, then maybe it is a matter of installing a lighter spring?

Jeep owners have this cheap mod where they install a spring on the outside of the waste gate that counteracts the spring inside, which is not easily accessible, and this lowers the spring pressure, thus lowering the boost.

 

[robvas]

You could run no spring and control pressure with CO2 if you really wanted to

However, the wastegate only bleeds off so much boost so there's a minimum it will make no matter what.

Why turn it down so low?

 

[GhastlyTT]

Turbo boost is controlled by a wastegate spring, so yeah, whatever the wastegate is sprung for will dictate your starting boost. A boost control solenoid is installed in-between the wastegate and the manifold (before the throttle body) to allow higher than sprung boost levels by manipulating the pressure the wastegate receives until the turbo produces the higher programmed pressure.

 

[135Hoser]

Magical AI can't answer this one? Geez.

Yes your wastegate spring dictates the lowest amount of boost its possible to run.

If you had a spring pushing against another spring, the spring being pushed upon would need to push harder (increasing boost)

You can also run less boost by not flooring it.

The wastegate / "boost control" solenoid also dictates the maximum amount of boost you can run, which is generally 2x spring pressure. If you found a really light 3psi spring, you might only make 6lbs of boost with 100% duty cycle.

Just get a full standalone ECU and chop up the car so you can run an electronically actuated wastegate.

 

[Junkyard Dog]

You could run no spring and control pressure with CO2 if you really wanted to

However, the wastegate only bleeds off so much boost so there's a minimum it will make no matter what.

Why turn it down so low?

I do not yet know how low. I am trying to learn from folks who actually know, what is possible? The idea, however, is to have a system that I can adjust, and maybe use a low boost for HPDE track days (5 psi?) and turn it up for other things (like making a grocery run ).

I don't want to tear into my short block and increase the ring gap, so running E85 and keeping the boost lower would keep the rings from expanding too much from the buildup of heat over a 20-30 minute run on track while still letting me turn up the boost higher when I am not going to be hammering the car full throttle again and again and again for half an hour.

Obviously, I would experiment with different boost levels . . . but first I was wanting to know what is possible.

Running quarter mile or a roll race on the interstate is not the same as a half hour of track time on a track with some long straights. Michelin Road Atlanta has a long straight where a regular S650 GT or Dark Horse can be well over 140 mph from a starting speed below 50 mph.

Turbo boost is controlled by a wastegate spring, so whatever the wastegate is sprung for will dictate your starting boost. A boost control solenoid is installed in-between the wastegate and the manifold to allow higher than sprung boost levels by keeping pressure below the wastegate trigger until the turbo produces the higher programmed pressure.

That is sort of what I have been learning by reading on the internet. There just is not a lot of information about lowering boost. The key seemed to be the waste gate spring pressure, however, as the minimum boost. Your post now tells me where the boost control is (between the waste gate and the intake manifold), which helps me understand a little more. Thank you for responding.

Magical AI can't answer this one? Geez.

Yes your wastegate spring dictates the lowest amount of boost its possible to run.

If you had a spring pushing against another spring, the spring being pushed upon would need to push harder (increasing boost)

You can also run less boost by not flooring it.

Yeah, I was trying to avoid AI and get some real responses. I figured we had some folks here with real world experience.

 

[robvas]

I don't want to tear into my short block and increase the ring gap, so running E85 and keeping the boost lower would keep the rings from expanding too much from the buildup of heat over a 20-30 minute run on track while still letting me turn up the boost higher when I am not going to be hammering the car full throttle again and again and again for half an hour.

You aren't going to be on boost for 20 minutes.

I would ask the Hellion Facebook group or email Hellion themselves. I'm sure someone has tried to run a minimum boost setup.

E85 helps against detonation but the 'cooler burning' isn't going to stop you from cracking a ring/piston, people do it all the time.

 

[Junkyard Dog]

You aren't going to be on boost for 20 minutes.

True, but the heat in the chamber and cylinder wall and rings will continue to build over that 20 minutes. It just is not the same as drag racing. E85 will limit the heat build up on the rings. Lower boost will also limit the heat build up (a sort of obvious statement, but, well, there it is. More obviously 0 boost would be no additional heat, right? LOL).

I would ask the Hellion Facebook group or email Hellion themselves. I'm sure someone has tried to run a minimum boost setup.

Thank you for that suggestion. I may very well do that.

E85 helps against detonation but the 'cooler burning' isn't going to stop you from cracking a ring/piston, people do it all the time.

Well, I guess I would dispute whether E85 would help with this or not (if you are even contending it would not help). Folks who "do it all the time" are probably going further than they would have or even could have gotten away with on just gasoline. That is not what we are talking about here. I am not looking to raise the boost due to using E85. I am just looking to keep the rings cooler than they otherwise would be running 93 octane, at a lower boost level for some extra margin of safety on a road course.

You did not actually say whether you think E85 makes any difference at all on ring temperature and the associated thermal expansion (until the gap disappears!). I am not disputing that folks damage their engines on E85, but you have to know a lot more than that one fact before you can draw any inferences from it relevant to the scope of this discussion.

(oh, and I could be completely wrong about E85 and a reduced thermal expansion of the rings compared to 93 octane - I honestly don't know this. It just makes sense).

 

[Junkyard Dog]

I also found a track guy over at TrackMustangs running turbos and seemingly solved the heat issues. I am going to ask him some, but his car is a full on trailered track car with lots and lots of mods, so I am not sure how much information can be useful to my more stock application. There is another build thread that a guy started, but he got upset at something somebody posted and quit the site before he took the boosted S650 on track.

 

[robvas]

You did not actually say whether you think E85 makes any difference at all on ring temperature and the associated thermal expansion (until the gap disappears!). I am not disputing that folks damage their engines on E85, but you have to know a lot more than that one fact before you can draw any inferences from it relevant to the scope of this discussion.

(oh, and I could be completely wrong about E85 and a reduced thermal expansion of the rings compared to 93 octane - I honestly don't know this. It just makes sense).

I'd like to see some numbers on EGT's and coolant temps and whatever else, doing pulls on e85 vs 93. I posted before some study Ford did and as far as exhaust manifold temps went there wasn't much difference.

For 20 minutes of load you're going to hit whatever danger zone there is, gas or e85

e85 'burns cooler' but I think people really overestimate how much and the effects (or lack thereof).

I mean we get people who say they run e85 and their car runs 10 degrees less coolant temp on the street....sounds as silly as the people who put a strut tower brace on and take their car around the block and talk about how it leans less and tightened it up...

 

[LouG]

Thought of 50/50 Meth/Water injection? It does what E85 does, but I believe it's more effective.

 

[Junkyard Dog]

I'd like to see some numbers on EGT's and coolant temps and whatever else, doing pulls on e85 vs 93. I posted before some study Ford did and as far as exhaust manifold temps went there wasn't much difference.

For 20 minutes of load you're going to hit whatever danger zone there is, gas or e85

e85 'burns cooler' but I think people really overestimate how much and the effects (or lack thereof).

I mean we get people who say they run e85 and their car runs 10 degrees less coolant temp on the street....sounds as silly as the people who put a strut tower brace on and take their car around the block and talk about how it leans less and tightened it up...

The most reliable coolant temp reduction from E85 on track I could find was one poster who stated 3° C (going off memory, so I could be wrong). Mainly I found lots of speculation, and, like you said, coolant temps just cruising around on the street, which is not particularly relevant to tracking. Even if there was a coolant temp reduction, which is nice, it does not mean that there is less heat in the piston ring and therefore less expansion. I do not know whether there is, or is not, less heat in the piston ring. All I can find are references to less heat in the combustion chamber.

 

[robvas]

Thought of 50/50 Meth/Water injection? It does what E85 does, but I believe it's more effective.

Meth setup/tune is more complicated (you have to pull fuel for the meth you add)

Chance that something goes wrong with the meth system, pump failure, clogged jet, doesn't turn on...

Your intake manifold was designed to flow air, not water mist/meth, you end up with unequal distribution

Most people will say you can't push meth+93 as far as you can e85

It has a few advantages, though. You can keep your existing fuel system since water/meth is all supplementary. Where with e85 you need bigger pump(s), injectors, etc at a certain point

 

[Junkyard Dog]

I found this discussion (2jz forum) where an engine builder is mentioning that you can tighten the ring gap a little using E85, but it depends upon boost and power level, as more power = more heat.

https://www.hpacademy.com/forum/gen...r a,* **Leakdown test** Monitors rate of wear

 

[robvas]

I wonder how much abuse a stock ring (no matter what the gap) engine would handle in a boosted drift car and if a different ring/piston all together is the solution

You see what those cars go through for a few laps

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