What does CID stand for???

***A20A1*** · 07-28-2002, 03:50 PM

What does CID stand for??? is it the displacement?

Length (in inches) = (CID x 1900) ÷ (rpm x pri.OD2)

I'm trying to tune a set of custom headers... I plan on using aftermarket headers for the mounting flange... but I'm going to have an exhaust shop weld on new tubes for a 4-1 desing instead of 4-2-1.

**smufguy** · 07-28-2002, 05:01 PM

i heard that 4-1 gives more hp gains than a 4-2-1 headers. and i got it convinced by the DC sports website. why go with the 4-2-1 design?

CID stands for Central Institute for the Deaf . hehehe nah.

here are what i found out for CID which might be related to ur use. but i have no clue what CID means or stands for

Change in Design
Component Identification (Number)
Component Identification Designator

***A20A1*** · 07-28-2002, 05:09 PM

I think it means cubic inch displacement... but I need to be sure. and is if for 1 cylinder of the overall engine displacement.

**smufguy** · 07-28-2002, 05:14 PM

oooh. i never heard of that term before. where is it used?

***A20A1*** · 07-28-2002, 05:19 PM

the equation calculates the length of the primary tubes based on (CID, RPM, the primary OD squared.... or primary outer diameter squared) I'm not sure what the 1900 represents but its a part of the equation none the less.

1988starter · 07-28-2002, 05:19 PM

I also think it is the cubic inch displacement

***A20A1*** · 07-28-2002, 08:19 PM

CID = 119
lets say the primary OD = 2"
For reference:
The pacesetter headers use a 1-5/8" OD
and a 2" collector... is the collector the same as the downpipe on the stock exhaust manifold... if so I'm going to make it 2.5" like the rest of my cat back.

Length (in inches) = (119 x 1,900) ÷ (rpm x pri.OD2)
Length (in inches) = (119 x 1,900) ÷ (7,500 x 2 squared)
Length (in inches) = (226,100) ÷ (7,500 x 4)
Length (in inches) = (226,100) ÷ (30,000)
hmm...
Length (in inches) = (2,261) ÷ (300)
Length (in inches) = ~ 7"

Hmm I hope I still can do math and don't make a fool out of myself by posting this...

it doesn't specify if it's lowest rpm or highest rpm... I used highest since I want to get the power up high.

hmm I wonder if it also applies differently for 6 and 8 cylinder cars... or maybe that was where the CID came in.

***A20A1*** · 07-28-2002, 08:29 PM

I wonder if I should tone it down to 1.75" OD
It should leave it close to:
Length (in inches) = ~ 11" ?

**POS carb** · 07-28-2002, 08:34 PM

don't go too big there, you don't exactly have a 427, 9,000 rpm motor in there

***A20A1*** · 07-28-2002, 08:43 PM

stop the insanity... stop the hyper avatar pic changing...

**doug** · 07-29-2002, 04:11 AM

ya know ya can turn off avatars? I did after my first visit here roughly two months ago. about CID, I think it's cubic inch displacement. A CID of 119 is a 1.2 liter. when speaking of engines.

**shepherd79** · 07-29-2002, 04:34 AM

i don't think so, 119 CI is the same as 1.995 liters that is what our eningine is.
and A20A1, after you did the calculatrions i think you should come up with like 7.53" which is .53" longer.

**doug** · 07-29-2002, 04:38 AM

yeah, you're right. hadn't had my morning fix yet.

1988starter · 07-29-2002, 07:21 AM

According to my owners manual it is a 119.

**offthahook** · 07-29-2002, 07:38 AM

Originally posted by shepherd79
i don't think so, 119 CI is the same as 1.995 liters that is what our eningine is.
and A20A1, after you did the calculatrions i think you should come up with like 7.53" which is .53" longer.

I thought we had 1955cc engines, which would be 1.955liters which we call 2.0L. CID is cubic inches displacement. However, most engines esp. smaller ones, use the metric system of cubic centimeters or liters when talking about size or displacement. In the day, you heard stuff like 350, 454, etc. That was CID...