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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 6:19 am Post subject: 87 z28 rear end |
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Ok so we are stripping the kids wrecked car that we ran a 14.4 at PIR with
Took the rear end out and looked at the gears.
They are 2:73 Yuck.... It’s some kind of limited slip rear as well.
My questions are,
How much time do you think we would gain if we put in a 3:73 ring a pinion in ? 1/2 sec ? Maybe more? This is a 10 bolt as well and an auto
Also what size is the carrier ? 7.5 7.6 I have been looking at ring and pinions and they always say they are for a certain size carrier, what size should this z28 have???
Things are taking much longer to do, lots of parts to take off and not enough time to do it. Haven't even started swaping anything to the vert yet.
Thanks much
scott |
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 7:10 am Post subject: |
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What were the 60ft times? You can't just change gears and have a specified go faster.
With those tall gears you have a 2 series carrier. It's smaller than the 3 series carrier which comes on 3.23 and up.
If you get 3.73 you'll need to find a gear set that is made THICK for the 2 series carrier specific. I'd recommend a standard 3 series 3.73 gearset and an Eaton 3 series posi unit.
Make sure if you change carriers you get the right one for your spline of axle.
If your 60ft time was say 2.5seconds, if you can get it down to 2.0 you can look to shave off 1/2 a second, maybe, if things go right the rest of the way down the track. |
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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 7:26 am Post subject: 60ft |
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I can't remember what the 60 ft times were.
I know he was at 98 mph at the end.
Iam pretty sure 3:73 will make an improvement, just was wondering how much? and thought Id ask the experts.
Almost ready to swap the stealth ram on as well, doing some light porting tonight
Going to do the rear as well, then swap everything over to the vert.
I think High School Drags are in August so we will be running if we can get er all done buy then.
I will have those 60ft times then.
Scott |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 2:41 pm Post subject: |
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| Are you planning on keeping the 700R4 in that car? If so, 3.73 is kinda high end for that trans. I like the kick of the line, but getting tractions becomes a real b****, and and I run out of steam at around 100mph. |
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QwkTrip 11sec Club

Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Jul 25, 2006 3:44 pm Post subject: |
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If your engine can rev then I think your guess of 1/2 second is as good as any. If it's more of a stock type TPI engine that coughs out when the revs climb then it may not respond that well. The TPI is really a low/mid range engine. It just won't pull well at 5000 rpm and higher. Using a higher stall torque converter will make it easier to launch with those gears and modulate throttle to control tire spin. A good torque converter can do lot for your '60 foot time.
Don't run the overdrive under full power. You will ruin the transmission in quick order. If 1/4 mile is your thing then choose gears and tire sizes that will put you near max engine speed in 3rd gear at the end of the track. |
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 6:17 pm Post subject: |
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You want to cross the finish line at your peak HP.
So... 5000k.
If you go too steep, you'll get out of the hole faster and run out of umph before the line.
Good call Qwk.
BTW, Aaron, 3.73 and 700R4 works just fine. Ran it for 2 years in my '85. No noticable difference in milage. |
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QwkTrip 11sec Club

Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Jul 25, 2006 7:39 pm Post subject: |
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.... can't we get a "What he said" sign instead?
3.50 to 3.73 gears are a great choice for street/strip with stock height tires. I chose the same ratio for use with my supercharged big block. I'm not going to complain about lack of traction. Find a way to hook it up!
This is just my oppinion, but I think it is easier to modulate wheel spin with a more agressive gear than a freeway gear. I suspect the reason why is that when traction is broken with 2.73 gears the wheel speed sky rockets and you have to let off the throttle to get traction again. Let off the throttle and you lose the race. With 3.73 gears it is easier to play the fine line between barely loosing traction and totally spinning out. Add a soft torque converter and a little suspension work and the car will transition from leaving the line to launching off the line.
Races are won and lost in the first '60 feet. Dust 'em off early to win. The rest is just running it out with horsepower.  |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Tue Jul 25, 2006 9:43 pm Post subject: |
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| Twilightoptics wrote: | You want to cross the finish line at your peak HP.
So... 5000k.
If you go too steep, you'll get out of the hole faster and run out of umph before the line.
Good call Qwk.
BTW, Aaron, 3.73 and 700R4 works just fine. Ran it for 2 years in my '85. No noticable difference in milage. |
Don't get me wrong, I like it, it's just that you're going to be crossing the 1/4 in third just above your HP peak with a stock TPI setup. With your Stealthram on there it would have been a real good combo though. |
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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 4:49 am Post subject: hey thanks |
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Wow thanks for the input,
Stealth Ram:
Iam going to order the fuel rail and adjustable regulator from summit today,
But I can't find it, do they still carry it??
I have the intake but not the other stuff.
thanks
scott |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 5:40 am Post subject: |
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Hmm... that's a little odd. They have a Holley AFPR listed for a 5.0 Chevy TPI, but not a 5.7. And they have a universal fuel rail, and a fuel rail for chevry trucks, but not one for TPI.  |
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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 6:01 am Post subject: |
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HLY-534-186
HLY-9900-172
thats what they have,
Are one of these correct????
If you are running the holley stealth are one of these correct?
thanks
scott |
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 8:12 am Post subject: |
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| Asdfga3 wrote: | | Twilightoptics wrote: | You want to cross the finish line at your peak HP.
So... 5000k.
If you go too steep, you'll get out of the hole faster and run out of umph before the line.
Good call Qwk.
BTW, Aaron, 3.73 and 700R4 works just fine. Ran it for 2 years in my '85. No noticable difference in milage. |
Don't get me wrong, I like it, it's just that you're going to be crossing the 1/4 in third just above your HP peak with a stock TPI setup. With your Stealthram on there it would have been a real good combo though. |
That's the idea dude.
I setup to cross the line at 6200rpm.
Because of other factors off the line(tire spin, slow on the throttle, etc), you go with the hair steeper gear that idealy would give you a HAIR too much rpm at the line, but you tend to not see it because of those launching factors you run out of running room.
Been to a dragstrip much?  |
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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Dewey316 The Lama

Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Wed Jul 26, 2006 8:46 am Post subject: |
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| No expert here, but the first set seems to be universal EFI rails. The second set, is the kit specific for the HSR. |
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scott in wa. Member
Joined: 10 Aug 2005 Posts: 660 Location: puyallup wa.
1988 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 9:52 am Post subject: yep |
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Yep I didn't see that.
Thanks Dewey
Ordered, will be here Friday.
I have a few more questions that I hope you all can help with.
Starting engine swap this weekend so here it goes.
88 vert 305 TBI car is getting the 350 TPI that’s in the 87 z28 (but with the stealth ram).
1. Fuel lines the same on the 88 TBI car? Will they work for the Stealth ram setup, are they the same under the car?(I will be changing the fuel pump)
2. Will the TPI Throttle body work on the stealth ram? (For now) or will I have to get an Lt1 type???
3 Iam switching harness as well, we took out the engine portion of the harness from the TPI car, is this all I need??
4.What about the ADL wiring??? Will it work as is? I want to be able to data log.
Iam using the same TPI computer it’s the 165, worked ok with the help from you guys on the custom prom stuff.
Anything Iam forgetting???
Thanks
Scott |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 12:36 pm Post subject: |
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| Twilightoptics wrote: |
I setup to cross the line at 6200rpm.
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At what MPH? Seems a bit high for a 3.73.
| Twilightoptics wrote: | Been to a dragstrip much?  |
Not as often as you, but I figured since I'm such a know-it-all I would automatically know it.
| Quote: | | 2. Will the TPI Throttle body work on the stealth ram? (For now) or will I have to get an Lt1 type??? |
Ya, it should work. Try this page: http://stealthram.com/costtoswap.html |
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rjmcgee The Hammer

Joined: 08 Jan 2004 Posts: 2328
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Posted: Wed Jul 26, 2006 2:02 pm Post subject: |
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I think when I chose my gear ratio It was 109 mph @ 6200 with the stock size tire. Worked great till I found out my valves float at 5500.  |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 2:34 pm Post subject: |
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| That sucks. What type of heads? |
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QwkTrip 11sec Club

Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Wed Jul 26, 2006 6:10 pm Post subject: |
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| Asdfga3 wrote: | | At what MPH? Seems a bit high for a 3.73. |
I have a better question. What's the point of nitpicking about details that are really none of your concern and no relation to you?  |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jul 26, 2006 7:20 pm Post subject: |
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| Curiousity, since I'm running the same gears, and wondering what MPH Paul was putting down. |
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