Are my 4.10s killing my boost?Thinking of changing to 3.73's

Primo

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Jun 9, 2003
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Phoenix
I do not see boost in 1st or 2nd with 4.10's. I only see about 10-5 HG in vacuum in 1st and maybe 1lb of boost in the top of 2nd. I know boost is correlated to engine load, so if I put more load on my engine, i.e. higher gears 3.73's will this net me more boost and HP? I need to do something anyway since I am running out of gear at the 1,100' in the 1/4 mile. I was either going to have T&J raise my rev limiter, get taller tires, or change the rear end gears. This is my daily driver and I can't get traction in 1st or 2nd on the street anyway.
 
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well 4.10's should get you into boost faster. the 3.73's would actually take longer to get the car into boost. but no doubt the 3.73's are a better gear for the s/c if you want to keep the stock tire size though. i think that there is something else besides the rear end gear to be causing your problem.

can you feel the car go into boost, but just don't see in register on the gauge???? or is there no boost in 1st & 2nd????
 
yes, it feels like I am in boost, but the gauge doesn't show it. Maybe I'll throw on my Track tires and see if spinning is my problem. I havn't had the gauges in while on DR's.
 
Primo said:
yes, it feels like I am in boost, but the gauge doesn't show it. Maybe I'll throw on my Track tires and see if spinning is my problem. I havn't had the gauges in while on DR's.
You should have your gauge checked. Maybe you have a bad blow off valve or a vaccun leak. I have 4:10's and make boost whenever I floor it. :D
 
Making boost does not have to do with load, you can make boost in neutral if you wanted. You probably have the same problem as me, traction. When you are instanly lighting up the tires you can not stay in the throttle or you will be bouncing off the rev limiter. My suggestion, find a way to get the power to the ground in 1st and 2nd so you can stay WOT and you will be seeing your boost on the gauge.
 
If I rev it in neutral, I do not see boost. I know for a fact that he stock bosch is a POS. Maybe that's my problem. I think I am the only one with an intercooled Novi 2K running the stock POS bosch bypass valve.
 
Hold the pedal to the floor in neutral and you will see boost, I personally wouldn't recommend it but if you don't mind bouncing off your rev limiter go ahead and try it.

There was a whole big thread in the power adder forum a while ago on this. A guy wanted to know if his clutch slipping was costing him boost.