Supercharge pulley question

[TROY09]

My setup for pulleys right now is stock upper 3.6 and lower +2. Making 10.5 psi of boost. car made 375 rwhp and 356 rwtq.
QUESTION
Is a 2.9 upper and +2 lower to much for a stock motor?

[parker]

No, I have a 2.76 upper and a +4 lower that's how I purchased the car and I use it as my DD.
But plan on switching to a 2.96 upper for more belt wrap when I get it ported.

[RubberCtyRauder]

Most recommend keeping stock motor in the 425 -450 range..the weak link being the rods and pistons. I run a 2.9 pulley, not sure of lower one. I have forged rods and pistons and am at 455 rwhp on a tune that isn't to the very edge..i could prolly be in the 470-480 range.

Added, I don't drive mine daily

[Ourobos]

I went through the same process, left mine with 3.6 and 2#. I'll be tuning it Thursday. I would leave it and be safe, just me

[justbob]

My setup for pulleys right now is stock upper 3.6 and lower +2. Making 10.5 psi of boost. car made 375 hp and 356 tq.

QUESTION

Is a 2.9 upper and +2 lower to much for a stock motor?


My old set up was originally 11.7#'s and no real mods and made 445/431. That was a stock lower and 3.2 upper. I wouldn't be in a hurry to jump down that far in pulleys on a stock block. Maybe start off with a 3.1 and see what that nets you.

Pulleys are cheaper than engines!


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[TROY09]

Thanks for the feedback.

[loud2004marquis]

Just for reference:

3.0 upper and +2 lower on mine with headers produced 13.7# boost. 432hp/463tq

[8UWITH6]

I have been running 11psi of boost for a year and a half and 10K miles. My engine has developed a bit of a noise but still runs awesome. I have heard it ping a few times depending on fuel type, outside temperature, and what gear I hammer it in. With this being said I would be careful when upping the boost on a stock block. I should have ran 9psi and played it safe. I was told by many 11psi was fine but obviously might be on the ragged edge in my case. This is mostly my fault since I am used to tuning Turbo Regal's which respond to timing/boost/fuel pressure very well. (I run 28psi of boost on a stock block GN). I just got greedy. I still drive it everyday, it runs great although I am not beating on the car quite so much. I am also looking for a short block to build just in case. Who knows the noise could be something else. But I just wanted to share my experience on an eaton swap stock block engine.

[RubberCtyRauder]

From what I understand the stock block and crank are not prone to failure.

[Ourobos]

Powdered rods and cast pistons.. Never meant to handle more than 400-450.. Been dealing with it in Mustangs since 1999.. Same components.

[jwibbity]

Your numbers seem a little low for 10+psi or is it just me????

[TROY09]

That's what I was thinking jwibbty . I thought I should be closer to 400 rwhp with 10.5 psi.

[RubberCtyRauder]

What octane is your tune? 91 ? 93? Who did the dyno tune? What time of year was it done at? If it was hot and humid, then timing will get pulled quickly as IAT rise.

[TROY09]

Did some research last night and it looks like a 3.4 upper and the +2 lower will be about 12 psi and keep it safe.

[parker]

Did some research last night and it looks like a 3.4 upper and the +2 lower will be about 12 psi and keep it safe.


Sounds about right, I have 2.76 upper and a +4 lower and my gauge is about 16-17lbs

[8UWITH6]

Did some research last night and it looks like a 3.4 upper and the +2 lower will be about 12 psi and keep it safe.

My car is 11 with a billet flow 3.4 upper and 2lb lower.

[TROY09]

91 tune. Last spring , temp was about 60 to 70 . Tuner was local but not very familiar with marauder. Just need to take a trip to Mo's this spring.

[RubberCtyRauder]

91 octane is part of the reason . If you can't readily get 93 then stick with 91 tuning. A trip to MOs is always good. Jeff can tweak it up. If you can datalog, they can remote tune it with great success. Maybe shoot Marty a pm

[TROY09]

Thank you very much for the feedback !!!