im thinking about getting a bigger cam (383) Please read! - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-08-2010, 07:18 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: USA
Posts: 218
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
im thinking about getting a bigger cam (383) Please read!

Hi guys, i have a 383 that has been built pretty well for power. Right now its putting out 365HP and 427TQ to the wheels. At first I ran the engine on nothing less than 93 octane. Then as my wallet got thinner, i started using 89 and performance stayed the same and the engine never pinged or dieseled. I took a risk and added 87 to the 89 just to see what would happen. I decided i would add 87 to the tank until it started pinging or dieseling (if ever) and would add 93 to the tank to even it out if it did. Well now the tank has pure 87 in it, and ive been running it with 87 for a month now. Engine performance is the same and it dosent ping or diesel. Timing is set at 30 total centrifugal all in at 1600 rpm and 20 degrees of vacuum advance. This setup has been great for me!

Anyway, even if i have a straight pipe on this engine, it just isnt very loud. Today an LT1 w/ trick flow heads and a bigger cam fired up, and even with pipes all the way back, it was loud! And it wasnt annoyingly loud, it sounded great! I want that sound and realize that I need a bigger cam, but I dont want to go too big on the cam so I dont lose all the mpg i gained by using a t56. Basically my cruising speed is 1600 to 1800 rpm doing 70-80 mph. I dont want the cam to have to much overlap and have all my fuel going through the exhaust because the cruising speed is lower than usual carbed v8's.

Right now i have a comp cam 510/520 lift w/ 230/236 duration 112 LSA. What would you guys recommend for a nice cam that has a nice THUMP to it, that would also give me some more power on the top end? The engine has a holley double pumper 750 on it and its in an 87 trans am (about 3250LBS) with a T56 6 speed manual and a 3.42 torsen rear end. What do you guys recommend?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-08-2010, 07:46 PM
Custom10's Avatar
my KARMA ran over my DOGMA
 

Last journal entry: SS
Last photo:
Join Date: May 2009
Location: Saskatchewan, Canada
Age: 49
Posts: 1,100
Wiki Edits: 0

Thanks: 18
Thanked 30 Times in 26 Posts
My gut feel on this is don't mess with a good thing seems like alot of work for something that is doing so well for you??,,, but its your deal so,,,

you already have a pretty big street cam, can a bigger cam live with your compression ratio? what is it at?

you could look for a similar cam but with a tighter LSA for a more agressive idle.

2 more of my cents
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-09-2010, 01:32 AM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: USA
Posts: 218
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
That makes sense, thanks.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-09-2010, 08:16 AM
Registered User
 
Join Date: Feb 2008
Location: cold upstate NY
Posts: 85
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
more rpm would = detination

It's kind of tough to put an exact handle on your combo w/o knowing the static compression. The 383 tends to reduce detonation tendancies due to the dwell of the piston near tdc. The cam you describe doesn't start building cylinder preasure until the rpms come past 3000 up due to the overlap. Most likely why your combo is quiet is because that it's burning the fuel much better than you friends combo that's what makes all the noise anyway.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-09-2010, 09:01 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,206
Wiki Edits: 0

Thanks: 17
Thanked 339 Times in 319 Posts
Quote:
Originally Posted by red65novawagon
It's kind of tough to put an exact handle on your combo w/o knowing the static compression. The 383 tends to reduce detonation tendancies due to the dwell of the piston near tdc. The cam you describe doesn't start building cylinder preasure until the rpms come past 3000 up due to the overlap. Most likely why your combo is quiet is because that it's burning the fuel much better than you friends combo that's what makes all the noise anyway.
Really?



Back to the OP, with such a low cruise RPM you don't want a larger camshaft, you can try holding the same intake duration and extending the exhaust duration but that will lower mileage. Narrowing your LSA will also lower mileage and make it harder to drive at that low of an RPM. To be honest it sounds like you have a really good combo, if you want a better sound try larger exhaust pipes and some good mufflers. Magnaflows make a sound that I LOVE and they are one of the least restrictive mufflers.

What are you currently running for pipes and mufflers? What size of headers?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 11-09-2010, 01:25 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: USA
Posts: 218
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by ap72
Really?



Back to the OP, with such a low cruise RPM you don't want a larger camshaft, you can try holding the same intake duration and extending the exhaust duration but that will lower mileage. Narrowing your LSA will also lower mileage and make it harder to drive at that low of an RPM. To be honest it sounds like you have a really good combo, if you want a better sound try larger exhaust pipes and some good mufflers. Magnaflows make a sound that I LOVE and they are one of the least restrictive mufflers.

What are you currently running for pipes and mufflers? What size of headers?
Right now Im running a 3" exhaust, y pipe going into an edelbrock true flow muffler w/ dual 2 and half outlets, w/ 4" tips. It dosent sound bad, but you cant even hear it at idle inside the car!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 11-09-2010, 02:00 PM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,206
Wiki Edits: 0

Thanks: 17
Thanked 339 Times in 319 Posts
IS it possible for you to get true dual exhaust (no Y-pipe)? That along with some flowmasters will get you a lot of noise. I still prefer magnaflow but flowmasters will give you more interior noise than you want!

What size of headers are you running?

It looks like your money would be be spent on getting a better exhaust if you want more sound.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 11-09-2010, 02:28 PM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 31
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
yes these cars can have true duals put on them, i run 3" true duals on my 87' camaro. but you will have to have it done at a shop, because it will be a custom exhaust. for mufflers i like Dynomax, for the money they are the best flowing mufflers, Magnaflow are really good but a little pricey too, i dont like flowmasters at all, they have proven that they dont flow nearly as well as some of the other companies out there (like the ones i just mentioned). i use dynomax bullets, 3" center in/out with a 4" outside diameter, my rear suspension is adjusted to about 1.5" higher too + i use a 28" tire. if your car still sits at the stock height then you will want to avoid all speed bumps, or you could even just use 2.5" duals and you should be fine, a 2.5 dual still flows enough to handle up to 500hp

get rid of the Y-pipe and make sure that you are running a decent 1 3/4" longtube headers
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 11-09-2010, 07:11 PM
Registered User
 
Last photo:
Join Date: Mar 2010
Location: USA
Posts: 218
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by my87Z
yes these cars can have true duals put on them, i run 3" true duals on my 87' camaro. but you will have to have it done at a shop, because it will be a custom exhaust. for mufflers i like Dynomax, for the money they are the best flowing mufflers, Magnaflow are really good but a little pricey too, i dont like flowmasters at all, they have proven that they dont flow nearly as well as some of the other companies out there (like the ones i just mentioned). i use dynomax bullets, 3" center in/out with a 4" outside diameter, my rear suspension is adjusted to about 1.5" higher too + i use a 28" tire. if your car still sits at the stock height then you will want to avoid all speed bumps, or you could even just use 2.5" duals and you should be fine, a 2.5 dual still flows enough to handle up to 500hp

get rid of the Y-pipe and make sure that you are running a decent 1 3/4" longtube headers
Ive been thinking about lifting the car a couple inches for a while, do you have any pics of lifted trans am/ camaros? Im planning on going for 18" vette wheels. If i can lift it, ill go for 3" duals since i already have most of the piping.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 11-10-2010, 07:47 AM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 31
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
to lift it you will need to buy new struts and shocks with knew springs, i acutally used QA1 adustable coil overs in all four corners with new springs, i had to do a little bracket fabrication but it was well worth it
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 11-10-2010, 11:22 AM
pepi's Avatar
How’s that hopey-changey thing
 
Last wiki edit: Determining top dead center
Last journal entry: Quicky frame dolly
Last photo:
Join Date: Mar 2005
Location: Georgia ... USA
Posts: 1,835
Wiki Edits: 8

Thanks: 0
Thanked 0 Times in 0 Posts
want loud, here in the car ................. side pipes, music to the ears and will give that hotrod a road racer look.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CAM HELP! Comp Cams XR276HR In a sbc 383 Chevystr383 Engine 24 01-02-2011 08:15 PM
Cam for 383 build v8hed Engine 32 03-23-2010 06:38 PM
Anybody dealt with this guy on ebay? Or through Dirttrackthunder.com? killerformula Hotrodders' Lounge 20 08-31-2008 05:12 PM
Chevy 383 What cam to run???? Also Forged or hyper pistons?? 89SDime Engine 19 02-27-2006 11:59 PM
383 stroker block and cam ???????? mupton Engine 1 01-26-2006 09:50 PM


All times are GMT -6. The time now is 11:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.