High compression and turbo

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Toluene56

Toluene56

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So, I have an idea. It might be a bad one. But then it might be a really fun one. I've been toying with the idea of building a turbo kit for a high compression stroker. (12.2:1)
Current engine specs
Magnum block
Forged pistons
Scat rods
Scat Crank
Trickflow 190 Heads
Howards solid roller (probably not the best cam for a boosted application)
257/267 @.050/108/.640int. .645exh. w/ 1.5 Comp Promag rockers
Edelbrock Super vic

Now If I go down this road. If I can stick to 100-110 octane fuel and use a methanol injection to help intake temps and still make decent or somewhat reliable power at say 6 to 8lbs of boost? Would it be worthwhile? Is the 6-8lbs gonna rock my world?

Possibly important note, I'm also at 4500ft base elevation. Compression test is 170-175 with current camshaft.
 
Toluene56 said:
So, I have an idea. It might be a bad one. But then it might be a really fun one. I've been toying with the idea of building a turbo kit for a high compression stroker. (12.2:1)
Current engine specs
Magnum block
Forged pistons
Scat rods
Scat Crank
Trickflow 190 Heads
Howards solid roller (probably not the best cam for a boosted application)
257/267 @.050/108/.640int. .645exh. w/ 1.5 Comp Promag rockers
Edelbrock Super vic

Now If I go down this road. If I can stick to 100-110 octane fuel and use a methanol injection to help intake temps and still make decent or somewhat reliable power at say 6 to 8lbs of boost? Would it be worthwhile? Is the 6-8lbs gonna rock my world?

Possibly important note, I'm also at 4500ft base elevation. Compression test is 170-175 with current camshaft.
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I wouldn't do it on gasoline. And spend for a custom turbo cam. It will spool quicker, put less heat in the exhaust etc.

Make damn sure you kill all quench and soften up the combustion chambers.

Do it like a Drag Week engine and do it with two fuels systems. One for gasoline to drive around on and the other for methanol for twisting up the boost.

With that CR I'd shy away from much boost on even race gas. Unless you call VP or ERC or Torco and let them pick your gasoline.
 
yellow rose said:
I wouldn't do it on gasoline. And spend for a custom turbo cam. It will spool quicker, put less heat in the exhaust etc.

Make damn sure you kill all quench and soften up the combustion chambers.

Do it like a Drag Week engine and do it with two fuels systems. One for gasoline to drive around on and the other for methanol for twisting up the boost.

With that CR I'd shy away from much boost on even race gas. Unless you call VP or ERC or Torco and let them pick your gasoline.
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VP Q16 is a good fuel but comes at a premium. But with that CR I’m not sure you got a choice. The 2 tank thing is a brilliant idea. But on even premium PG i would always be worried. I personally would get a custom grind turbo spec cam. They can get you more in the ballpark with your specs.
 
yellow rose said:
I wouldn't do it on gasoline. And spend for a custom turbo cam. It will spool quicker, put less heat in the exhaust etc.

Make damn sure you kill all quench and soften up the combustion chambers.

Do it like a Drag Week engine and do it with two fuels systems. One for gasoline to drive around on and the other for methanol for twisting up the boost.

With that CR I'd shy away from much boost on even race gas. Unless you call VP or ERC or Torco and let them pick your gasoline.
Click to expand...
Yeah, I figured 6-8lbs would be max with a 100+ octane. from what I understand meth injection works pretty well to help control the intake charge. As far at quench goes, .041 is number I settled on when I built the engine, and rings are already gapped for boost or a healthy shot of giggle gas (although they were gapped just in case I got a wild hair up my ...).

and the chambers..
61224728_10211245288286861_3137541852463366144_n.jpg
 
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J Glenn said:
Why not use an inter-cooler?
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at the moment i'm not that great at tig welding or welding anything aluminum. So custom building an intercooler to fit how I want it to fit, isn't exactly in the cards at the moment. Maybe when I have some more practice and feel comfortable doing it. At least with a meth injection setup I can kinda get my feet wet in the performance turbo arena and add an intercooler later.
 
You can run water/meth injection if you choose to run non-intercooled.
 
I was also wondering about E85. Is this going to be blow through carb or fuel injected?
 
What’s holding the bottom end together in that? If just the stock bolts and caps, you may want to at least add studs and a girdle. Just my 0.02. I like the thought of a separate fuel system with methanol with nitrous. That cam would be just okay for either boost or oxidizer if it was on a 112 or higher LSA, but still not as good as custom opening and closing rates. Also, what is feeding and controlling spark right now and what do you plan on for boost?
 
Have you considered just building a low compression block for this purpose? Or even trying it on a stock 360 Magnum block? Just throwing this out there as my two cents instead of hurting what could possibly be a good high compression engine...
 
Soemthing to consider....they cut cams up to 134 degrees of LSA.


Here is a typical small block turbo cam grind....

228/240 dur @.050", .630"/.612" lift, 118 deg LSA
 
Garrett Ellison said:
What’s holding the bottom end together in that? If just the stock bolts and caps, you may want to at least add studs and a girdle. Just my 0.02. I like the thought of a separate fuel system with methanol with nitrous. That cam would be just okay for either boost or oxidizer if it was on a 112 or higher LSA, but still not as good as custom opening and closing rates. Also, what is feeding and controlling spark right now and what do you plan on for boost?
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Everything is arp, except caps are still stock. Engine was built to run a small shot of gas. all msd ignition at the moment. If I boost, there are some pretty decent msd controllers around that would make everything function. This just an idea to see if it's even feasible.
 
j par said:
Have you considered just building a low compression block for this purpose? Or even trying it on a stock 360 Magnum block? Just throwing this out there as my two cents instead of hurting what could possibly be a good high compression engine...
Click to expand...
Yes. Just tossing ideas around so people that have done it would chime in and give me something to think about. This engine has this car mid 11s @7,900ft DA. So it might make it's way into another project or the turbo build might make it's way into another project. But the thought of a high compression boosted dart makes me all sorts of giggity.
 
Couple of points, with that much compression your tuning window will be very small regardless of fuel used. The common understanding is either higher compression and low boost (10:1 and 10ish psi) or low compression and higher boost (8:1 and 20ish psi). You didn’t say if this was a street car or race car, or both, but IMO its to dicey to do a boosted street/strip car with that compression. Race car only is a different animal. If you decide to try I’ll make a few suggestions. I wouldn’t attempt this without standalone EFI, I use AEM infinity. Blow through and a standard distributor can work but precise control of fuel and spark will be the keys to making this work. I wouldnt do it without a custom grind cam, work with a cam grinder familiar with turbos. I wouldn’t do it without an intercooler, unless on methanol. Meth injection on top of gasoline is a crutch at best and shouldn’t be relied on in the tune up. FWIW everything I own is turbocharged, in that car 8-10 psi even at 9:1 compression and the correct cam, will be mind blowing the first time you stand on the loud pedal. Have fun.
 
abdywgn said:
what about E85?
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That is a real good option IF you can get it and IF you buy the hygrometer to verify its actually 85% ethanol because it can only be 85% maximum but it can and often is say under 85%.

If I could get it here my next build would be 13.5-14:1 and I'd love it. But I can't get it.
 
Garrett Ellison said:
What’s holding the bottom end together in that? If just the stock bolts and caps, you may want to at least add studs and a girdle. Just my 0.02. I like the thought of a separate fuel system with methanol with nitrous. That cam would be just okay for either boost or oxidizer if it was on a 112 or higher LSA, but still not as good as custom opening and closing rates. Also, what is feeding and controlling spark right now and what do you plan on for boost?
Click to expand...


Funny...I was going to run NO2 with alcohol over injected alcohol.

I made some calls to the guys that know and everyone to a man said don't do it. All the alcohol and the nitrous would pull all the heat out of the engine and it would be a massive power loser.

They said run the engine on gasoline and use alcohol over the nitrous.
 
Toluene56 said:
Yeah, I figured 6-8lbs would be max with a 100+ octane. from what I understand meth injection works pretty well to help control the intake charge. As far at quench goes, .041 is number I settled on when I built the engine, and rings are already gapped for boost or a healthy shot of giggle gas (although they were gapped just in case I got a wild hair up my ...).

and the chambers..
View attachment 1715422677
Click to expand...


Yeah, you need to kill that quench and then "soften" up those chambers.

Quench and compact, "tight" chambers hate boost.
 
What YR said. Leave regular fuel system as is and then alcohol for nitrous enrichment in the second fuel system (didn't fully clarify that). Or use e98 for a big dose of nitrous. e98 has a very high latent heat of evaporation rating and will cool as much as methanol for a given amount of nitrous even though the fuel enrichment is close to half for ethanol vs. methanol. I was going to mention E85, but only in drums unless you plan on a fuel density meter with input into engine management for fuel control. Pump e85 is still a crap shoot, at best. It runs from 51% to 90% blend just depending on what the vendor is trying to predict is going to yield the highest profit and least amount of potential trouble for FlexFuel vehicles using it. If I chose to go with pump e85, I'd keep e98 on hand and use a hydrometer to blend fuel to the tune, being I prefer the simplicity of the analog world. But either way you go, the chambers are going to need opened up. Overall, I think boost with some compression drop from softening the chambers and some thicker gaskets to minimize quench (along with adding water/methanol injection) would be doable, but not practical. The more compression you can get out of it, the better. I can say from experience that 8 PSI of Roots boost on top of 9.5:1 compression is fairly unmanageable for most street usage.
 
I should clarify, when I say meth injection I am speaking about the commonly used water/meth systems available in the aftermarket. While they do work to pull heat out of the charge, it seems the guys that rely on them in the tune blow their junk up when the tank runs dry. I believe it is better to have a safe tune up for the fuel being used without relying on the water/meth to be safe. Again I am speaking about a street/strip deal not a race car.
 
Toluene56 said:
Blow through.
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Never mind on the E85 then. As mentioned the pump E85 is a crap shoot and it would be a nightmare getting your tune right. Only way I'd go E85 is with fuel injection and a flex fuel sensor.

Just be very very careful with the tune and that compression. I am running 9:1 with 10 lbs of boost..... pump gas with a mixure of 110 race gas. Ended up with too much timing and my pistons blew chunks, literally.
 
Walker434 said:
Never mind on the E85 then. As mentioned the pump E85 is a crap shoot and it would be a nightmare getting your tune right. Only way I'd go E85 is with fuel injection and a flex fuel sensor.

Just be very very careful with the tune and that compression. I am running 9:1 with 10 lbs of boost..... pump gas with a mixure of 110 race gas. Ended up with too much timing and my pistons blew chunks, literally.
Click to expand...
E85 isn't available here, I can buy c85 and e98 in bulk. But honestly I might just change the head gaskets and stick with this being a nitrous engine. Then build my other 360 block to handle the boost. Wonder how many people I would piss off putting a Mopar 408 in a little Ford ranger. Lol
 
Or maybe convert everything to run on alcohol. Then boost it. That would limit the street driving even more, but damn would it be cool. So many decisions and choices.
 
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