Performance Questions About Gears and Exhaust

[Lowflight]

Gears:

Will 410 gears drop my Quarter Mile Time?
Do you have to retune the chip to correct the Speedo?
Do they make 6th gear more like 5th?
What is the top speed reduced to?


Exhaust:

Headers will make my B&B Exhaust (old style Mufflers with latest gen Resonator) Intolerable won't they?

[bradslt5]

on if they drop your times i am not sure . it gets tougher to get traction plus the extra shift . i personally am going to try 3.73 and 410s at the next 2 day test and tune in my area . i mght also try the 3.45s if time allows . on the street 410s make 6th gear cool . 72 mph is 2000rpms and passing you just click to 5th a off ya go . have noticed that fuel milage has gone down 2-4 mpg but that might be a right foot problem:mrgreen: . if you go to 410s you have to by the plastic gaers that go into the trans to keep the speedo right . they arent cheep about 120 from mark . if you go with 3.73s that price goes to 20-30 from gm. i am kinda thinking that 3.73s might be the best overall gears. easier to get traction at the strip and just the perfect cruizing rpms for gas and no lugging . but that is just my opinion .petes fully ported 350 has gone in the 11.30s with 3.45s

[Lowflight]

Also, would these lower gears keep the RPMs up more when driving and actually reduce the resonance of the exhaust? As it sits, I can't drive in 6th without every part made of plastic in the car vibrating....

[Nick]

Gears: Will 410 gears drop my Quarter Mile Time?

Maybe. I hope so, as I just went to 4.09's. :D

Do you have to retune the chip to correct the Speedo?

No. You have to a) change the transmission speedo drive and driven gears, or b) add an electronic speedo correction box.


Do they make 6th gear more like 5th?

Yeah, that's kinda the description I'd give. I am much more apt to use 6th gear on 70 mph (or under) freeway speeds now that I was with stock gears.

What is the top speed reduced to?

Dunno; haven't gotten that far in the research yet. :mrgreen:


Exhaust: Headers will make my B&B Exhaust (old style Mufflers with latest gen Resonator) Intolerable won't they?

Well, how well do you hear now? If not very well, it won't matter. If pretty well, you won't be able to hear very well soon enough if you go with that combo!. :wink:

[bradslt5]

on the exhaust all depends on where the reasonance is . i got totally rid of it by going to that x pipe reasonator that dyno max makes .its 3in inside weather you have 21/2 or 3in in and out pipes. now its quiet without powerloss. borla recently came out with their exhaust for the c-6zo6 that is using an xpipe reasonator .hope this helps

[Aurora40]

I've heard about .2 or so reduction in the 1/4 mile factoring for the extra shift.

5th gear is .75 and 6th is .5. So to really make 6th like 5th, you would need a 5.18:1 rear end. But it's somewhere in the middle. Top speed becomes limited by RPM. 7,200 rpm gives you something around 173-175mph I believe in 5th gear.

[Lowflight]

Though more expensive, porting the heads would give me more power in the 1/4 mile.

[Aurora40]

Though more expensive, porting the heads would give me more power in the 1/4 mile.
I think so. At BG, I was paying attention to Keith's car. He has headers, cat-back, and 4.10:s. I have headers, cat-back, and porting (both are '90s). I believe he was running in the 12.7-12.8 range? I was running in the 12.5-12.6 range. Perhaps he'll weigh in to clarify his times though.

[Lowflight]

With regard to exhaust, I am trying to work around my B&B. I have the early mufflers and later resonator...so my system is probably 12% louder than a brand new set in terms of resonance and general sound. If I added headers, I would probably go crazy. I prefer the look of the B&B tips and don't want to go to Corsa in terms of looks cost of switching and all around hassle.

So, I want to do as many mods as possible without adding headers right now.

[Hammer]

From what I can tell, looking at all the times on the Registry, with 3:45 gears, your best 60' times are going to be around a 1.95. All the Z's running 1.6's to 1.8's (modded or not) were running 4:10's. I think this would be where you pick up your E.T.'s.

[1990 quasar blue]

So, I want to do as many mods as possible without adding headers right now.

I wonder how much they will reduce the benefits of the other mods. Especially porting the heads.

[Jeffvette]

From what I can tell, looking at all the times on the Registry, with 3:45 gears, your best 60' times are going to be around a 1.95. All the Z's running 1.6's to 1.8's (modded or not) were running 4:10's. I think this would be where you pick up your E.T.'s.


Not true John. I pulled a hellacious 60 foor in Peavens stock geared car at BG this past year. And in my car, I got some good 60 foot times with the 3:45 gears on stock tires. What really matters is track prep, and being able to just flat out be lucky. :D

[UKZR1]

I have the old style B&B's running on a 368 with no cats, jeal headers and xpipe. I have just received my 410's from Marc and hope to get everything sorted in the next few weeks. One of my aims is to make the car driveable in 6th gear at 70-80mph without making my ears bleed with that dam resonance. At the moment I tend to drive without using 6th unless cruising over 100. So I am hoping for a slight mpg improvement - a good thing as fuel prices are now $8.46 for a US gallon:mad:

[blackjack]

im planning to use cats with my headers,as im sure they will cut resonance to an acceptable level,without eating too much power...i have 4:10 right now,but one of these days i want to try 3:73 or 3:90,to get a more ''civilized'' first gear
bj
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