Has anyone pondered the idea of using 10.1:1 compression pistons and other upgraded internals along with a small amount of boost? I searched and could not find much on this. I'm trying to find the ideal part by part build up scheme. By using a slightly higher compression than stock, other stronger internals, and more aggressive cams maybe I could slowly inch up on the 200+ whp mark steadily with each upgrade and still eventually install some type of forced induction (options are still open here, but I hope to avoid a turbo). I'd like to avoid a turbo because I plan on doing all the installs with me and my buddies. Would this be a worthwhile modding idea?
low boost with higher compression?
PastyPyro
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Has anyone pondered the idea of using 10.1:1 compression pistons and other upgraded internals along with a small amount of boost? I searched and could not find much on this. I'm trying to find the ideal part by part build up scheme. By using a slightly higher compression than stock, other stronger internals, and more aggressive cams maybe I could slowly inch up on the 200+ whp mark steadily with each upgrade and still eventually install some type of forced induction (options are still open here, but I hope to avoid a turbo). I'd like to avoid a turbo because I plan on doing all the installs with me and my buddies. Would this be a worthwhile modding idea?
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SVT's come with 10.2 stock, they've been boosted fairly safely (intercooled) into 8 or 9 psi at least, possibly more.
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The problem is that more compression doesn't really gain you that much more power. Especially not in comparison with how much power you can get with more boost.
I believe each point of compression nets about 2% more power, whereas each additional psi of boost is about 9% (14.7/15.7) (and of course boost seen at the gauge is actually not what you want to see, you want flow... but still). Could be totally incorrect ricer math. So hopefully someone will correct me if this is wrong. I just wish I could remember the source I got this from....
Either way, higher CR equals much less boost friendly, and once you've tasted the boost, you will definitely be craving more. So raise CR just seems like a dead end street to me.
Higher CR + nitrous might be a better path than high CR + boost though. Then again, I know virtually nothing when it comes to nitrous.
I believe each point of compression nets about 2% more power, whereas each additional psi of boost is about 9% (14.7/15.7) (and of course boost seen at the gauge is actually not what you want to see, you want flow... but still). Could be totally incorrect ricer math. So hopefully someone will correct me if this is wrong. I just wish I could remember the source I got this from....
Either way, higher CR equals much less boost friendly, and once you've tasted the boost, you will definitely be craving more. So raise CR just seems like a dead end street to me.
Higher CR + nitrous might be a better path than high CR + boost though. Then again, I know virtually nothing when it comes to nitrous.
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Also, why avoid a turbo?
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I read the same thing also, but I don't see people running 7:1 compression ratio. You would only loose 6.2% power base on what you said, but gain more hp with boost. I think it is true to a certaint point, so I would only lower it to 9:1 CR.
Kenne bell turbocharger performance guide says 1 point CR = 3-5 octane. 1 psi of boost requires 1-1.5 octane(minimum), so 1 CR lower = 5-2 psi boost increase or we will say 3.5psi average. 1 CR = 2% hp. 1 psi pf boost = 6.8% hp max. One could say lower the compression on my engine to 7:1 CR from 10.2CR currently. 10.2-7.0= 3.2CR *2%hp loss = 6.4%hp loss . 150fwhp - 6.4% = 140.4 fwhp @ 7 CR. A svtf can run 9psi safe with 93 octane, so 9psi + 3.2CR * 3.5psi for each CR drop = 11.2psi more boost. Thus, Someone can run 20.2 psi of boost with 93 octane making 332hp at the wheels !
6.8% each psi * 20.2psi of boost = 137.36% more power + 140hp, which is 332 hp.
Kenne bell turbocharger performance guide says 1 point CR = 3-5 octane. 1 psi of boost requires 1-1.5 octane(minimum), so 1 CR lower = 5-2 psi boost increase or we will say 3.5psi average. 1 CR = 2% hp. 1 psi pf boost = 6.8% hp max. One could say lower the compression on my engine to 7:1 CR from 10.2CR currently. 10.2-7.0= 3.2CR *2%hp loss = 6.4%hp loss . 150fwhp - 6.4% = 140.4 fwhp @ 7 CR. A svtf can run 9psi safe with 93 octane, so 9psi + 3.2CR * 3.5psi for each CR drop = 11.2psi more boost. Thus, Someone can run 20.2 psi of boost with 93 octane making 332hp at the wheels !
6.8% each psi * 20.2psi of boost = 137.36% more power + 140hp, which is 332 hp.
I was hoping to reach NA power similar to an SVT. Is the block the same strength on the SVT as on 130hp motor? The whole purpose of going through this slightly higher compression, slightly less boost is to be able to keep the NA power before I can afford a supercharger, turbo, or nitrous. This means that all the money you spend on initial upgrades are not simply thrown away once you have forced induction. An engine head and cams is almost always less than $1000 less than any worthwhile form of forced induction. Or I could go the total opposite way and get a vortech supercharger and lower compression pistons, engine head, cams, all that good stuff but pretty much be forced to do it all at once. But hey the second option sounds like it might be worth it. Does anybody around here have something similar to either of these setups?
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Lourenco - what kind of Torque/WHP (flow) are we talking about on a SVT at 9 PSI? Unless the method of FI is using a restrictive pump, like my like Aerocharger, or the SVT is somehow less deto prone than the ZX3 despite the SVT's higher CR, 9 PSI on 93 octane "safely" (without water injection, etc.) sounds extremely optimistic to me
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Tom says this on his website " Early numbers have shown an awesome 239whp @ 9psi on Pump Gas! " . This is on his svtf. Tom recommends running 8-9psi, which Tom has said is safe on the svtf. You have to remember svtf already comes with a worked head with larger valves, a higher lift cam, a better flowing intake manifold, forge connecting rods and so on. The engine is arleady built up compared to a regular zx3.Lourenco - what kind of Torque/WHP (flow) are we talking about on a SVT at 9 PSI? Unless the method of FI is using a restrictive pump, like my like Aerocharger, or the SVT is somehow less deto prone than the ZX3 despite the SVT's higher CR, 9 PSI on 93 octane "safely" (without water injection, etc.) sounds extremely optimistic to me![Image]()
Now just think how much boost and hp my car can make with a complete built engine with 9:1 CR.
This is exactly the kind of information I wanted from this thread, thanks. I'd like to build up a strong motor with any compression greater than or equal to the original compression in the ZX3 (9.6:1 I believe). Ford racing head, cams, forged rods, new pistons, and all the misc. stuff that I have not totally researched yet. But the NA build would be a prerequisite to a boost application. I believe the upgrade to 10.1:1 compression would have only a slight impact on the boost possibilities but add alot of total strength to the engine.
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This is exactly what baffles me, the SVT breaths better than the ZX3 so at 9 PSI it would be flowing more air (and fuel) and encountering higher chamber pressures, not to metion a healthy compression increase at the same time.Tom says this on his website " Early numbers have shown an awesome 239whp @ 9psi on Pump Gas! " . This is on his svtf. Tom recommends running 8-9psi, which Tom has said is safe on the svtf. You have to remember svtf already comes with a worked head with larger valves, a higher lift cam, a better flowing intake manifold, forge connecting rods and so on. The engine is arleady built up compared to a regular zx3.Lourenco - what kind of Torque/WHP (flow) are we talking about on a SVT at 9 PSI? Unless the method of FI is using a restrictive pump, like my like Aerocharger, or the SVT is somehow less deto prone than the ZX3 despite the SVT's higher CR, 9 PSI on 93 octane "safely" (without water injection, etc.) sounds extremely optimistic to me![Image]()
Stronger internals are not a factor in this - they have no bearing on the tendency to detonate or not, and deto is not acceptable regardless how strong the internals are.
I know Tom's "pump gas" has been like 100+ octane in the past as some of his local stations despense race gas out of a pump - making it "pump gas".
Anyhow it seems unlikely to me this could be done on 93 safely without other things like a Safeguard, water injection, etc.
Tom makes 239hpfwhp with 93 octane on his svtf. With 110 octane he makes 325fwhp. Tom reduces the timing enough, so there is no problem with detonation. Tom's kit comes with a big intercooler and an efficent turbo to keep the tempatures down.
The more mods a car has the more boost the car can run. Saleen09 svtf vortech car made 266fwhp with 8psi of boost, but only had problems since it was running too lean. If he ran 11.5 a/f, he would of been okay. He did not have any problems with detonation. His intake tempatures were very low with the vortech aftercooler. The svtf engine is just built alot better.
Your turbo might be inefficent or your engine needs to built up or something. I would think your compression psi would be low with all that detonation you had on your car. Letting the car detonation without pulling timing like your car did before would make the engine weaker.
The more mods a car has the more boost the car can run. Saleen09 svtf vortech car made 266fwhp with 8psi of boost, but only had problems since it was running too lean. If he ran 11.5 a/f, he would of been okay. He did not have any problems with detonation. His intake tempatures were very low with the vortech aftercooler. The svtf engine is just built alot better.
Your turbo might be inefficent or your engine needs to built up or something. I would think your compression psi would be low with all that detonation you had on your car. Letting the car detonation without pulling timing like your car did before would make the engine weaker.
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Incorrect. Up'ing the compression will seriously affect your boost possibilities. Your options will be run only race gas, or not run nearly as much boost.
Again, up'ing the CR is only worth about 2% power and you'll be working yourself into a corner if you plan to go with much boost. This is the reason, most of us with SVTF's are looking to drop our CR.
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If you look at Toms turbo kit for the regular Focus and SVT you'll see they are making almost identical power at the same boost levels. Granted the SVTF has a better flowing head and intake, it still makes barely 5-10whp more than a stock block zetec and head. On race gas they are also making the same power levels. Couple that with the fact that the SVT is heavier than a stock Focus, it seems like there's no point in getting an SVTF, OR modifiying your engine to have higher compression with boost. You'll just have to pull more timing on the SVTF or higher compression engine to make boost safe, so that will nulify the flowing advantage of the SVTF engine.
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Cause the Vortech sucks on stock Zetecs. First of all the SVTF is a better flower straight from the factory in every way, plus the SVTF is a higher reving engine than the stock Zetec so since it makes it's boost at a higher RPM vs Toms kit it, will make more HP if you rev it higher. I'd like to see a 250whp Vortech SVTF with a stock redline, cause no way I'd rev higher than stock on a stock block, even the SVTF, with boost. Then there's the lack of TQ of the Vortech.
And remember not all boost is created equal. A bigger turbo will put out more HP for a given boost level, vs a smaller turbo. My turbo puts out 9psi and does 200whp vs Tom's that does 8psi at 230whp, but mine spools up by 2800rpms vs Tom's that spools by 3200rpms. It's all in the turbo sizing.
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Though I still haven't dyno'd mine on a Dynojet, if you take the percentage gains from the baseline before and after dynos, my car was putting down right about 249 whp and 194 ft/lbs in the Dynojet world. And that was with a stock redline on 91 octane.
250 whp with the stock redline is a piece of cake with the Vortech kit. Especially if you scrap the 91 octane tune.
250 whp with the stock redline is a piece of cake with the Vortech kit. Especially if you scrap the 91 octane tune.
What do guys think would be the ideal engine set up for a ZX3? Like I said I'd like to avoid a turbo because I'll be doing all the labor myself and it will be a daily driver. I'm not looking for some insane boost numbers but "just" looking to hang with stock V8s and things like that. I'm not expecting to just be able to bolt on a supercharger and be able to run 13s and 14s. So with a budget of $7,000 - $8,000 (total, over time) what would you guys do with a ZX3 performance wise?
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