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Discussion Starter · #1 ·
I have a stock VR6 MK4 with about 90k miles on it. I got a garrett T3/T4 turbo .60A/R cold side .82 A/R hot side. ATP MAnifold. I will be using an intercooler. I'm building my own SRI. Will be C2 software w/ #42 injectors. What PSI would be safe to run with this setup? I would like to get 250-300 whp.
 

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<300HP: under 12 psi, 36# or 42# injectors w/programming
300-350HP: 12-16 psi, 42# injectors w/programming, 9:1 or 8.5:1 headgasket, shortrunner intake (must have past 12 psi), ARP headstuds
350-400 HP: 16+ psi, 60# injectors w/programming along with the stuff already mentioned previously, might wanna upgrade ARP rodbolts/studs, 3" exhaust (if you're at this point and don't have it you'll rob HP)
400+ HP: might as well go full race, daily driving a 400 HP beast would be a challenge let alone the gas costs. new rods, pistons... pretty much new engine.
but you stated you wanted to achieve 250-300 HP, i'm at 260ish with 7psi on a TO4B so its not difficult and i'm still on stock internals and still running my stock manifold, so its do-able what you're thinking, might have to run a little higher psi but you can do it
forgot to mention, the numbers posted above are based off a straight T4 turbo, not T3/T4, so the psi for a T3/T4 will be slightly higher


Modified by Jimbo1080 at 6:53 PM 3-19-2008
 

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Discussion Starter · #8 ·
Re: Stock VR internals. What can it handle? (Salsa GTI)

Thanks for the input guys. Greatly appreciated. I was thinking of running maybe 5-8 psi. How many WHP approximately will I get on that PSI? how long will stock clutch and tranny hold up with that?
 

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Re: Stock VR internals. What can it handle? (vdubtoews)

Quote, originally posted by vdubtoews »
Thanks for the input guys. Greatly appreciated. I was thinking of running maybe 5-8 psi. How many WHP approximately will I get on that PSI? how long will stock clutch and tranny hold up with that?

8psi = (1+0.55)*174Hp = ~270Hp
 

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Re: Stock VR internals. What can it handle? (Noobercorn)

the 0.55 in the equation = 8psi/14.7psi...
it is a rough estimate....basically to double the crank hp of an engine, run a bar of boost... http://****************.com/smile/emthup.gif
 

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Re: Stock VR internals. What can it handle? (dubdoor)

Density Ratio = ((Tin + 460) / (Tout + 460)) * (Pout/Pin)
With that being said, and assuming you have 100% efficient IC and compressor wheel, your density ratio becomes your pressure ratio, which at 8 psi would be ((8 + 14.7) / 14.7) = 1.55
And since density ratio is directly proportional to CFM (which in turn translates directly into power), you'll be making 1.55 times more power than what you are making now. 174hp * 1.55 = 270 hp
 

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Re: (KillaVR6)

Quote, originally posted by KillaVR6 »
your nuts my friend runs 16 on stock internals.its been that way for a while and not a single problem.

been running 15psi all day long. gotta be sitting 340/350whp .. no issues as well

the real limits you need to look into are the limiting factors...like your intake (plastic mani = 13/14psi maxxx ) and rod bolts, which iirc will be the first thing to go under load
 

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Re: (IN-FLT)

Quote, originally posted by IN-FLT »

been running 15psi all day long. gotta be sitting 340/350whp .. no issues as well

the real limits you need to look into are the limiting factors...like your intake (plastic mani = 13/14psi maxxx ) and rod bolts, which iirc will be the first thing to go under load

Rod bolts ?
Did over 450whp on everything OEM+spacer
Now 540whp still oem bolts
 

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Re: (IN-FLT)

Quote, originally posted by IN-FLT »

for some reason i was under the impression they were the first thing to let go
but u know how missinformation floats around.

Not really misinformation.You have to remember the 1.8T forum is where we saw the "rod bolt letting go" scenario's.If the AEB & 9A motors can take 400whp on just ARP rod bolts then I see no reason why the VR6 cant take 600whp on just ARP rod bolts.The rods themselves are hella beefy.People just go forged for that sense of added secuirty....hell thats why I went with aftermarket rods,otherwise I would have thrown some ARP rod bolts in there and called it a day.
 

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Re: (Wizard-of-OD)

ive pushed 24psi on stock internals, arp headstuds and a spacer...which is over 450whp...and had no issues http://****************.com/smile/emthup.gif id have no issues doing at least 20psi daily on a stock motor with that same stuff..stock VR rods just shot peened can take a beating...only weak part at that point is the pistons
 
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