2nd Gen. hybrids - what's the best way to go?

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Originally posted by ITSRX7:
The header, expansion chamber and muffler set-up they sell for ITS RX-7's. I had a Racing Beat header into a custom 3" into the same muffler they sell (Ultra Flow)

AB

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Very interesting. Do you know:
1) Does the header contribute significantly to the improvement? and
2) Is the expansion chamber compatible with the RB header?

Do you have (or have seen) comparitive dyno runs? Curious about how the torque curve changes. I'd expect the expansion chamber to be tuned to an RPM band, like you get with two-stroke bikes - different pipe for low or high end.

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Marty Doane
ITS RX7 #13
CenDiv WMR

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Originally posted by ITSRX7:
So they are using the 146hp engine and you have the 160hp setup. There is 10 RWHP right there. And if you believe the info on the S5 intake, add nother 4-5 for that.

AB

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Isn't the S5 intake already part of the 160 hp setup?

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Marty Doane
ITS RX7 #13
CenDiv WMR

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Originally posted by theenico:
...as well as a 5.12 R&P.

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How would you compare a 5.12 vs a 4.88 vs a 4.10? Not an insignificant cost difference to go from 4.88 to 5.12. Big difference? Depends on the track? Not as good for some tracks?

Thanks,

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Marty Doane
ITS RX7 #13
CenDiv WMR

[quote]Originally posted by Eagle7:
[b]

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Originally posted by theenico:
...as well as a 5.12 R&P.

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How would you compare a 5.12 vs a 4.88 vs a 4.10? Not an insignificant cost difference to go from 4.88 to 5.12. Big difference? Depends on the track? Not as good for some tracks?


Marty:

The 4.10 is useless. You are giving up a ton in acceleration in each gear. Think "low E.T." in the 10 or so drag races you do each lap (from corner apex to braking point of each turn). Remember, the 4.10 slows you down in all the gears.
4.88 vs 5.13.
If you are spending $ to buy a new gear, go for the 5.13. Either one you choose will also require you to rebuild your tranny with the GTU-S 5th gear, as you will now use 5th gear at almost every track you go to. If you were using the 4.10, the improvement with a 5.13 and the GTU-S 5th is easily 2 seconds per lap at any track.
Down here in the SEDIV, everyone runs the 5.13, at all the tracks including Daytona.

P.S. What drivetrain components do you run?
Motor? S-4 or S-5 ?

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Originally posted by carlos e gutierrez:
P.S. What drivetrain components do you run?
Motor? S-4 or S-5 ?

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I got the car last winter. It claimed to come with a '90 engine (not yet confirmed) that turned out to have bad apex seals. I put an S4 engine in and used the S5 intake. The original engine gets rebuilt this winter. Do you know how I can confirm whether the original block is an S5?
I've got several transmissions, including at least one of each ratio, but I've not yet gotten into 5th, so which one to run hasn't mattered.
Car came with a 4.10 welded diff, which burned up at my first school (don't ask). I replaced it with a junkyard 4.10 LSD that slips.

Thanks,


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Marty Doane
ITS RX7 #13
CenDiv WMR

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Originally posted by carlos e gutierrez:
Down here in the SEDIV, everyone runs the 5.13, at all the tracks including Daytona.

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How about clutch LSD vs Torsen? Primarily a maintenance issue or a real performance difference?

Thanks,

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Marty Doane
ITS RX7 #13
CenDiv WMR

To tell the difference of the "block" look for the EGR valve. S4s have them on the top of the center housing. S5s have a machined flat where the valve used to be. The important thing is the rotors. The S5 rotors have the combustion dimples machined in the rotor with a fairly smooth surface. The S4 rotors have a cast combustion dimple.

After driving both Torsen and clutch type cars I like the Torsen. The only problem is that Torsens will still unload if a wheel comes off the ground. May be a problem heading in to the bowl at Grattan? That's the only place I've been that I can really see a problem.

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Chris Ludwig
08 ITS RX7 CenDiv

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Originally posted by C. Ludwig:
To tell the difference of the "block" look for the EGR valve. S4s have them on the top of the center housing. S5s have a machined flat where the valve used to be.

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S4 it is - bummer. I've got a full set of new S5 housings, and see the difference you described. All 3 of my engines are S4.

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<font face=\"Verdana, Arial\" size=\"2\">The important thing is the rotors. The S5 rotors have the combustion dimples machined in the rotor with a fairly smooth surface. The S4 rotors have a cast combustion dimple.</font>

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Anyone know where I can pick up a couple S5 rotors?

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<font face=\"Verdana, Arial\" size=\"2\">After driving both Torsen and clutch type cars I like the Torsen. The only problem is that Torsens will still unload if a wheel comes off the ground. May be a problem heading in to the bowl at Grattan? That's the only place I've been that I can really see a problem. </font>

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Yeah, I've been smoking the right rear through that corner. I also hear a little RPM blip cresting the rise on the long sweeper after the bowl.

Thanks,

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Marty Doane
ITS RX7 #13
CenDiv WMR

On my old cheapo Koni shocks I used to unload the right rear going into the bowl very badly. Pick the tire up, let off the gas, wait for it to set down, back on the gas. BAD! With no other changes and the new custom Bilsteins the problem was not quite totally eliminated. To the point you could stay on the gas atleast. I've never had a problem exiting the bowl on that next rise.

That is with a old, blown stock LSD. Haven't driven with a Torsen at Grattan.

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Chris Ludwig
08 ITS RX7 CenDiv