Compression to high for blower?

[VetteC501]

I'm looking at a GT with...

Block: .020 overbore 1999 Teksid-cast SVT Cobra, deep-skirt, SAE 319-modified aluminum alloy
Crank: SVT, forged, fully counterweighted, knife-edged, “eight-bolt,” neutral balance
DSS billet aluminum Main Support System main cap girdle
ARP Main studs
Federal-Mogul Crank bearings STD
DSS 4340 forged steel H-beam rods
Federal-Mogul Rod bearings STD
ARP2000 rod bolts
JE forged 2618 aluminum flat-top pistons, 10.2:1 CR, full floating pins, dual spirolocks
Piston rings: top ring 1.5mm, 2nd ring 1.5mm, oil ring 3.0mm.
SHM billit oil pump gear
HV oil pump
Accufab billet trigger wheel
Canton Windage tray
Canton Road Race pan
SVT 1999 aluminum tumble-port DOHC (“C”) heads, 4 valve, 37mm intake, 30mm exhaust, 52.6cc, 177cc intake ports
Ford Multi-Layer Steel (MLS) head gaskets
ARP 12-point head studs
SVT Valve covers
Ford Racing Performance Parts (FRPP) chrome ignition wire / coil covers
Camshafts: stock, 0.395 / 0.395-inch lift; 1.900-inch base circle. Duration at 0.050: 232° intake; 236° exhaust
Valvetrain: stock valve lash adjusters, 1.79:1-ratio rocker arms, polished timing chains, ovate-wire beehive valve springs and stock retainers
Fuel: 2003 Cobra gas tank, 2003 Cobra dual fuel pump assembly, 5/16-inch OD fuel line, SVT fuel rail assembly, 24-pph fuel injectors
MM Oil Filter relocation Kit
Induction: PHP High-Flow Air Box, K&N filter
stock SVT MAF sensor
stock 99 cast-aluminum intake, extrude honed by SVT
stock 57mm twin bore throttle body

(Taken from the forsale thread on another site.) Is that 10.2:1 to high for a blower on a modular motor? I'm really looking to TT it eventually so would that be dangerously high CR?

...I'm more of a bowtie guy for now, I haven't a clue on how these motors work best!

edit: Missed the extra "o" in too in the title!

 

[FATPAUL]

Ugh

 

[Whizzle]

It is a little on the high side for pump gas

 

[VetteC501]

Yeah since the Vette is 8.5:1, I assumed 10.2:1 would be a little high. But my Vette is a dyno queen lol.

 

[Mike@TF]

yeah 10.2 is very high.. that motor was made for nitrous easily..... so just spray the piss out of it... well a good 150 shot

 

[Helomech74]

That compression is just fine. I am running flat tops in mine with 14 pounds of boost on 93 octane with a good tune (still room to play with pump gas). No issues at all. Hell, I believe the stock compression on my motor was 9.8:1, my current compression is 10.3:1 so we aren't even talking about a whole point. I wouldn't hesitate to throw any boost at that motor at all.

 

[meaty mac]

i didn't know they made teksid blocks in '99-better check that out

 

[01yellercobra]

i didn't know they made teksid blocks in '99-better check that out

The 99 Cobras have the Teksid. Even some of the early production 01's got lucky and have it as well.

 

[Sniperdog]

seems high

 

[Posi]

It would be to high for me.

 

[JAILBAIT]

Are the combustion chambers on the heads opened up at all? If so a piston from JE that is supposed to be 10.2:1 might actually be lower.

In all honesty I have seen plenty of cars with well built motors like yours run 10 psi with no problems. Just remember some sort of intercooling will be your best friend.

 

[ProChargedSnake]

The 99 Cobras have the Teksid. Even some of the early production 01's got lucky and have it as well.

Dont think so... better run a block serial # check. The 99's had aluminum blocks, but not Teskid

 

[no_slow_svt]

Dont think so... better run a block serial # check. The 99's had aluminum blocks, but not Teskid

dude 99 percent of 99's have the teksid blocks
or at least 99% of the cobras did.
98 and 99 are the main years for the teksid.
also a lot of 01's are finding they also have the teksid

 

[D's01Snake]

Dont think so... better run a block serial # check. The 99's had aluminum blocks, but not Teskid

Are you retarded? All 99's had teskids. Hell even my 01 came with one.

 

[mystical]

That compression is just fine. I am running flat tops in mine with 14 pounds of boost on 93 octane with a good tune (still room to play with pump gas). No issues at all. Hell, I believe the stock compression on my motor was 9.8:1, my current compression is 10.3:1 so we aren't even talking about a whole point. I wouldn't hesitate to throw any boost at that motor at all.

+1. Machs come with 10.1:1 and do just fine boosted besides the weak internals. As long as you tune for it, you will be fine. Besides, low comp with a centri isn't much fun down low.

 

[LS1PUSSOUT]

all you need to do is run a good intercooler and possibly even some meth injection. You could also run race fuel but that gets expensive...

 

[D's01Snake]

all you need to do is run a good intercooler and possibly even some meth injection. You could also run race fuel but that gets expensive...

+1 on the meth.

 

[NXSVTCOBRA]

amazing that people give advice and have no clue whatsoever about what they are talking about.

for a centrifugal supercharger (i.e. procharger, vortech, novi) the compression ratio is perfect for a 4v motor. you'll need some sort of intercooler which most kits come with. you can run pump gas and be fine. i have a customer with a flat top piston 4v motor and a d1 procharger @ 23psi with a mild tune, the bottom end power it produces is out of this world. 9.5:1 would be ideal but 10.5 is good as well

 

[Helomech74]

amazing that people give advice and have no clue whatsoever about what they are talking about.

for a centrifugal supercharger (i.e. procharger, vortech, novi) the compression ratio is perfect for a 4v motor. you'll need some sort of intercooler which most kits come with. you can run pump gas and be fine. i have a customer with a flat top piston 4v motor and a d1 procharger @ 23psi with a mild tune, the bottom end power it produces is out of this world. 9.5:1 would be ideal but 10.5 is good as well

Exactly. I'm running flatops with compression at 10.3:1 and I do just fine (only 14psi though). Once I get the fuel system built, the boost will be cranked up.

No need for Meth injection unless you feel like using it. Just make sure to plumb in a nice A/A intercooler or aftercooler setup and you'll be fine.

 

[01yellercobra]

Exactly. I'm running flatops with compression at 10.3:1 and I do just fine (only 14psi though). Once I get the fuel system built, the boost will be cranked up.

No need for Meth injection unless you feel like using it. Just make sure to plumb in a nice A/A intercooler or aftercooler setup and you'll be fine.

Are you running 91 or 93 octane?