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I've been looking over warmonger's excellent excel spreadsheet files. I've got a few questions about the charge compression sheet... How can turbo'd cars get away with such insane amounts of boost on pump gas? For instance a stock VW 1.8T runs 0.8bar of boost with a 9.6:1 CR. That would make the effective CR 17.28:1, well into deto land. On top of that a common mod is to add a MBC and run 22-24psi. How is that possible on 93 octane? Are the motors soo overbuilt that they can just take the deto? They also sell upgrade kits with a larger turbo to run 350+ HP all out of that little 1.8t, all on pump gas.  I've also read about the turbo dodge guys running 34psi on pump gas with a CR of 8:1. WTF? School me wise turbo gurus. 
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list. 
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timing, A/F, all have to do with it...you need to focus more on cfm than psi.
98 E0 SVT with some stuff
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Head design, construction and materials used plays a huge role in this as well. Different heads have different quench characteristics.
That's the extent of my knowledge; if anybody wants to clarify in further detail I'd be very interested in reading more!
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Originally posted by stilov:
you need to focus more on cfm than psi.
You are getting too hung up on boost numbers. Boost is just the meaure of restiction/resistance. Actual cfm flow is what's important.
For example. A T2 at 20psi (maybe 250cfm) or a T66 at 5psi (650cfm).  Exactly my point...
As for high cfm flow and dynamic compression on pump gas. PROPER TUNING!
2000 SVT #674
13.47 @ 102 - All Motor!
It was not broke; Yet I fixed it anyway.
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Exactly as Demon said, PLUS the effect's of charge air temperature, spark timing, shape of the combustion chamber and piston face...this list goes on.
2000 SVT Turbo 295hp/269ftlb@12psi
#1 for Bendix Brakes Kits!
Knuckles rebuilt w/new bearings $55
AUSSIE ENDLINKS $70
Gutted pre-cats $80/set
A lack of planning on your part does not constitute an emergency on mine!
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Originally posted by DemonSVT:
As for high cfm flow and dynamic compression on pump gas. PROPER TUNING!
Exactly. Jon at HKS(not sure his last name), just hit 300whp on 91 octane(!!) on a totally stock Focus block with stock rods, pistons and compression(9:5:1). Basically he's got a huge turbo and intercooler and cams and a trick intake and exhaust manifold. He used stand alone engine managment and ran a 10.3.1 airfuel ratio. He did say he doesn't think the engine will last long at that power level, but he did run 250whp for two years.
The OEMs typically tune conservatively for maximum durability so when you get the car on a dyno with a good tuner you can get some good gains.
2000 Rio Red I4 Cougar
200whp & 210wtq at 9psi
254whp & 276wtq with NX 35shot
WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip
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That's really amazing. I'm kinda bummed though. I was hoping that there was some concrete way that I could determine maximum boost. I guess I'll just have to give it a try and watch for deto.
My Zetec buildup is going to use a FRPP head, FRPP intake manifold, FRPP exhaust manifold, Crower Stage 2 turbo cams, 8:1 forged pistons, forged rods, billett main caps, and ARP hardware EVERYWHERE. It will be interesting to see what it will be able to do. 
BTW, somebody bought that HKS Focus and put down 450WHP on C14 race gas. Unreal. Check it out.
Thanks everyone.
BP
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list.
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FRPP exhaust manifold? Are you going turbo or super, cause you won't get high numbers with a SC compared to a turbo.
Ultimately you'll have to go to the Focus forums to get the best Zetec tech for FI. They're doing around 300whp on pump gas on built blocks these days.
You'll also want to get the J&S Safeguard.
2000 Rio Red I4 Cougar
200whp & 210wtq at 9psi
254whp & 276wtq with NX 35shot
WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip
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Originally posted by ButtonPuncher:
I'm kinda bummed though. I was hoping that there was some concrete way that I could determine maximum boost.
You need to get the thinking out of your head that maximum boost equals airflow.
You can easily estimate power from the compressor map, VE, and engine size. That is more then enough to tell you what boost range you are shooting for on "that specific" compressor combonation.
If you can't do that then you definitely want to look into having someone else do the compressor sizing. I am taking for granted someone else is doing the tuning!
2000 SVT #674
13.47 @ 102 - All Motor!
It was not broke; Yet I fixed it anyway.
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Seawulf, I'm going to be using the shorty FRPP header. It is perfectly matched to the FRPP head. Plus it has a beefy bracket betweet the head flange and the cat/turbo flange for better restance against cracking. Yeah, I'm going to be getting a J&S. They seem like pretty kickass units.
DemonSVT, I realize that flow kills boost anyday. I know how to determine the power output from a comp map. That part is easy. What I'd like to know is the maximum boost that I can run on a built Zetec. According to all of the math, anything over a PR of 1.8 will land in deto. From what everyone is saying, you can't determine maximum boost from just the effective CR alone. That is painfully obvious with the Focus guys running 300WHP on pump gas with a 9.6:1 CR.
Yes, I will be doing the tuning. First I will tune it NA, get that down rock solid, then throw the turbo on with low boost and go from there.
BP
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list.
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