402R vs 402SR

madmaxx · #1 (**permalink**) 01-14-2008, 02:03 PM

Does anyone know the advantages of one over the other? It appears the 402R has about 50hp more than the 402SR so why would anyone choose the 402SR?

Thanks

RodKnock · #2 (**permalink**) 01-14-2008, 02:13 PM

The SR (street) engines have a dual plane intake instead of a single plane and the camshaft profile is smaller. It just depends on someone wanting their HP at a higher RPM or less HP at a lower RPM. Everyone is different.

smeredith · #3 (**permalink**) 01-14-2008, 02:53 PM

Take a look at the tourqe. I went with the 427SR because it had a little less HP than the 427R but the tourqe was the same, just at a lower RPM. I liked the ability to snap the unknowing passengers head back with a little tweek of the throttle.

ekrupa2 · #4 (**permalink**) 01-14-2008, 04:17 PM

Maxx - ditto to the replies. I choose the 402SR with Twisted Wedge cam. I thought it would be a little smoother at idle and quieter compared to my friends 427IR. It's not. Still waiting for my first test drive after install.

madmaxx · #5 (**permalink**) 01-14-2008, 06:52 PM

Thanks for the replies!! I have a difficult decision to make. I love the fact the 402r has the 500hp but the consensus appears that 402sr has more accesible horsepower. What hp numbers did you guys get with your sr's?

Got the Bug · #6 (**permalink**) 01-14-2008, 07:27 PM

The test tag that came on my 402SR shows 486 HP and 490 Torque.

http://www.clubcobra.com/photopost/d...F_2613_011.jpg

The 402SR has a nice idle and will run at 2K rpm all day long in 5th gear without bucking. Plenty of get up and go.

ekrupa2 · #7 (**permalink**) 01-14-2008, 07:32 PM

Maxx - my 402SR had 494HP at 5900 RPM and 481TQ 4600 RPM.

madmaxx · #8 (**permalink**) 01-15-2008, 05:55 AM

Once again thanks!! I can live with what numbers you guys got and thanks again, great photo!!. Roush websight indicates a maximium of 435hp and 455hp with tw cam on the 402sr. Your numbers look much better.

efrost · #9 (**permalink**) 01-15-2008, 06:24 AM

Quote:

Originally Posted by Got the Bug

The test tag that came on my 402SR shows 486 HP and 490 Torque.

http://www.clubcobra.com/photopost/d...F_2613_011.jpg

The 402SR has a nice idle and will run at 2K rpm all day long in 5th gear without bucking. Plenty of get up and go.

Got the Bug,

What heads did your Roush come with? The 2004 vintage Roush 392AL that’s in my car has Dart 195's. The peak engine dyno numbers are 447hp@5600 and 484tq@4100. I have toyed with the idea of changing these heads to a more exhaust friendly head (AFR’s) but with the expense of the heads plus new headers the installed price seems to outweigh the gains. Assuming a 70 hp/?tq gain the upgrade would be in the $35/hp range.

Btw, my engine looks identical to yours…. Alternator configuration, polished option and valve covers. Roush puts together a very nice package.

Thanks in advance,

Ed

Got the Bug · #10 (**permalink**) 01-15-2008, 08:25 PM

Quote:

Originally Posted by madmaxx

Once again thanks!! I can live with what numbers you guys got and thanks again, great photo!!. Roush websight indicates a maximium of 435hp and 455hp with tw cam on the 402sr. Your numbers look much better.

Madmaxx - I see 430/470 for the 402SR and 450/485 for the 402SR W/TW. Go for the 402SR W/TW.

http://www.roushperformance.com/engines/engines.shtml

Ed - Good question. I'm not sure what heads come on the 402SR W/TW.

Eric - I would think that the IR would be smoother at idle. Sound wise, I can't tell much difference between the 427 Roush and the 402.