jr and exaust and cams

[lsn2ocivic]

i have a civic with an ls motor in it im about to buy a jackson charger and i was wondering what size exaust i should run if they like back pressure or not and ive heard rumors that the chargers dont like aftermarket internals i have a set of crower 403 cams should i sell them and use stock or could i tune them to the charger

thanks for the help


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[UberLude]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lsn2ocivic:
i have a civic with an ls motor in it im about to buy a jackson charger and i was wondering what size exaust i should run if they like back pressure or not and ive heard rumors that the chargers dont like aftermarket internals i have a set of crower 403 cams should i sell them and use stock or could i tune them to the charger

thanks for the help


<HR></BLOCKQUOTE>


Aggressive all-motor cams will probably be detrimental to an FI setup, so stock cams are probably preferable. As for other internals, they can only be made better with stronger/lighter rods, pistons, valves, etc.

Your best bet with exhaust would be one with at least 2.25" inner diameter straight through. Optimal would probably be 2.5" ID, but to get all the benefits from that you'd need a header with 2.5" outlet (like the kamikaze or JDM headers) and a high-flow cat.

Cheers,
Ben

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99 Prelude SH
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The world isn't run by weapons anymore, or energy, or money. It's run by little ones and zeros, little bits of data---it's all just electrons.

[SuperTeg]

Whas up dude!

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As long as its fast!

[HyBridEX]

I believe there's a guy on this board with an SC LS with cams in it (blownLS)?
Talk to him about his setup.

Good Luck.

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95 EX Coupe w/SC'd JDM B16 @9 psi
http://community.webshots.com/user/hybridex

[blownLS]

Here is my reply to a similar topic last month. I hope this helps......

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Hi I am new here to this site. I am a Meteorologist with a bad habit, I spend too much time and money into my 94 LS Integra. I hope some of my weather knowledge of pressure, temperature and humidity helps to answer some questions about my favorite topic, HP and going fast.
So here is the answer to your question:

Yes it would. It changes the amount of overlap in cam timing. Anything can effect boost pressure.

I have adjustable cam gears. By changing the cam timing, I can make my normal 6psi reading (average from 4000-redline) increase or decrease 1psi. Believe it or not, but my fastest times at the track and highest dyno numbers (avg not pk) was at the 5psi setting, not 7. The difference was .4 seconds at the track.

A temperature or dew point difference can also change it. I get 1/2psi more boost in the winter than in the summer, due to cold and dry versus hot and humid. A 50 degree drop in temperature or dew pt (water takes up space) will give you 5% more oxygen molecules per square inch. More air=More power.

Its all relative man.

One important thing to remember, Boost is not a measure of how much air is going into your engine, but just a barometer in your intake manifold measuring pressure that builds up inbetween intake cycles. In a nut shell, what I am saying is, its a false way of measuring how much "extra" air is going into our engines. Think of it this way: Picture 6 people being shoved into a room up against the door. Now when that door opens(vavle) there's only enough time (cam timing) for 3 people to get out before the door closes. So, while those 3 people are in the next room, another 3 people slowly gets added to the room before the process repeats itself. But if you hold the door (valve) open longer (bigger/longer duration cam) you now will be able to get 4 people out the door before it closes. Now you are left with 2 people in the room. This room is where PSI is being read, if less air (people) occupies this space psi will drop. This is why bigger cams, ported heads or anything else that helps more air to get into your engine drops your manifold pressure or PSI.

You want the extra air in your engine, not making pressure in the intake manifold. So more boost does not always mean more power. I proved that on a dyno. No matter what your boost meter measures, the blower is moving at a specific rpm. This blower (M45)is blowing 45 cu inches (.75 liters) of air per 1 RPM. So, if you are NOT increasing the blower speed you are NOT increasing the amount of air that does go into the manifold. The blowers job is done. Its up to the head to determine how much of this air makes into the engine and how much gets left behind.

Chris
94 Blown LS (5psi with engine work)
dyno 181/158
13.98@97mph
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To answer your other question. 2.25" would be ideal for a stock B18A/B with a stock JRSC 6psi b18a/b kit. BUT, if you are flowing more air with larger cams, more boost etc... go with 2.5" from the collector thru the cat and thru whatever muffler you get or have. NO STOCK CAT!

I am currently changing my setup. I am going with 8.7 compression, 8-9psi, water/alcohol injection, Crane 8000rpm cams, 2.5" race cat, 2.5" b pipe, port-matched JSRC intake man to my already proted head, 8lb flywheel and either a B16A or B18C1 tranny. Everything is complete except a tranny.

The JRSC LS kits only flow 4% less air than the JRSC GSR kits. So, if you were to put a GSR replica cam into a LS you would make the same HP as they do from 4400-8000rpm. Their stock kits Peak at 208HP. But you have to rev it to 8000rpm to get it. And below 3000rpm your torque would drop off to a sputtering, sluggish wuss. It would have to idle at 1200rpm to stay running. The cams i went with kind of meet in the middle. I will not be able to use rpms below 1700rpm (so what) and my idle will have to be raised to 900 rpm (so what)!

Hope this all helps....
Chris
13.98@97mph with JG 1001 mid-range cams.

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