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Discussion Starter #1
I'm 100% noobie at this kind of stuff.. I was just wondering any decent mods to my car that could make it a bit better, while not completely ruining mpg and normal driving life? 2002 intrepid sxt 3.5 HO all stock
 

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Intake is an easy one to start at, from there I moved onto exhaust. Those things won't really effect your mileage, but it might increase it just a hair. Now if you wanted to get into performance one of the members makes an intake spacer which lowers the torque curve giving you a better acceleration at high rpm. There is also the 2.7L/ 300m special gears (3.89) which is a pretty big acceleration difference, but it has the sacrifice of around 1mpg, these gears topped with a special pcm is a great combo. You can also get bored throttle bodies for a little bit more oomph. Other than that it goes to custom and what crazy things you can come up with.
 

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Discussion Starter #5
Intake is an easy one to start at, from there I moved onto exhaust. Those things won't really effect your mileage, but it might increase it just a hair. Now if you wanted to get into performance one of the members makes an intake spacer which lowers the torque curve giving you a better acceleration at high rpm. There is also the 2.7L/ 300m special gears (3.89) which is a pretty big acceleration difference, but it has the sacrifice of around 1mpg, these gears topped with a special pcm is a great combo. You can also get bored throttle bodies for a little bit more oomph. Other than that it goes to custom and what crazy things you can come up with.
How much would one be? And what's the difference between different priced ones? Sorry when I said noobie before it was really meant :/
 

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How much would one be? And what's the difference between different priced ones? Sorry when I said noobie before it was really meant :/
Intakes are usually around $200, the only intake I'll really recommend is J-intakes.com because that's the only intake I have ever used.
Exhaust is more so custom and depends on what you want
Intake spacers are around $175 and are sold in the buy/sell/trade section by a member
3.89 gears can run you from around $50-$75 and will give you the most performance increase.
2002-2004 special pcm has quicker shifts supposedly and are around $150 I think
Bored Throttle bodies cost I think around $100 on maxbore.com. You send him yours or another throttle body and he bores it and sends it back.
 

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Well it's mid to high due to it kicking in around 4000 rpm. It's not exactly low rpm I would say, or at least what the dyno graph showed for it.
I'd have to look at the details. People are always saying it gives more performance off the line where our cars are somewhat lacking - that without the spacer, the torque band is to the higher rpms and with the spacer, it increases torque at the lower rpm end with little loss at the high rpm end. In any case, it shifts the power band towards the lower rpms. I guess I was challenging where you said the intake spacer gives you "better acceleration at high rpm". I think it adds at the low end and takes away slightly at the high end.
 

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I'd have to look at the details. People are always saying it gives more performance off the line where our cars are somewhat lacking - that without the spacer, the torque band is to the higher rpms and with the spacer, it increases torque at the lower rpm end with little loss at the high rpm end. In any case, it shifts the power band towards the lower rpms. I guess I was challenging where you said the intake spacer gives you "better acceleration at high rpm". I think it adds at the low end and takes away slightly at the high end.
You could most definitely be correct. I guess what I mean was higher rpm not specifically like 6k+. My bad. I don't specifically think it gives more off the line because I remember the power kicking in at around 4k rpm and adds nothing below it or at least what I remember from the dyno graph.
 

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That's probably why people talk about also using the high-stall torque converters - so that you're already closer to that power band from a standstill - so the spacer *and* the high stall converter together are even better than just one or the other by itself.
 

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Besides the basics like a cold air intake and an exhaust, and any other factory equipment you swap or bolt on, know that you are not playing with a Honda Civic that has endless bolt on goodies. You want to look good or go faster, you're going to have to either put in the wrench time and work around many engineering challenges... or have the money to pay people too do it for you.

That said, you can make just about anything kick a Ferrari's ass... These cars are a WAY better baseline then any Honda.

- True dual exhaust (two pipes all the way to the back), or open up what you have half an inch wider proper consistent diameter tubing.

- Cold air intake will give it grunt, better acceleration and a few horses. Strapping a cone filter six inches from your exhaust manifold is NOT a cold air intake. Do it right, move your battery to the trunk, cut the battery box out and run the filter down in the bumper.

As far as factory equipment... Well there is LOTS of cool things you can add for looks and function if you know or see what you want and grab it at the junk yard. But there are a few performance tweaks...

- If you have no intentions of any independent fuel or ignition systems, a computer (PCM) from a 2002-2004 300M SPECIAL will give you a real nice edge. More aggressive tune, and the transmission shifts quicker and firmer.

- Change your transmission gears to the one found in any LH car that has a 2.7, or find a 300M Special. You can access the gears from the panel at the rear of the transmission once you remove the mount. Easy easy easy job. For the cost and work involved, this offers the BEST difference in power. If you got money to throw away, find a set out of a Prowler, or get a set of Prowler Pro Gears.

- Police/Special Sway bars, they offer a 35% gain in cornering performance, also the springs are stiffer.

Now for the real stuff...

- You can build a stroker out of your 3.5... Would require you to get a 4L crank, pistons, rods, bearings/rings. Appropriate machine work and you got a real nice torque difference.

- Turbo it... Which is my end goal.

- Inerita Performance offers a few goodies for our motors... From three stages of cams, to port and polished heads that optionally offer bigger valves.

- Bore out the throttle body (about $100).

- Intake Spacer kit was mentioned, something worth adding.

- Port and polish your lower intake manifold

- Can try a LX intake manifold swap

- High stall torque converter

- Limited slip differential

I'll go on, but your bank account is likely empty.
 

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Discussion Starter #11
Besides the basics like a cold air intake and an exhaust, and any other factory equipment you swap or bolt on, know that you are not playing with a Honda Civic that has endless bolt on goodies. You want to look good or go faster, you're going to have to either put in the wrench time and work around many engineering challenges... or have the money to pay people too do it for you.

That said, you can make just about anything kick a Ferrari's ass... These cars are a WAY better baseline then any Honda.

- True dual exhaust (two pipes all the way to the back), or open up what you have half an inch wider proper consistent diameter tubing.

- Cold air intake will give it grunt, better acceleration and a few horses. Strapping a cone filter six inches from your exhaust manifold is NOT a cold air intake. Do it right, move your battery to the trunk, cut the battery box out and run the filter down in the bumper.

As far as factory equipment... Well there is LOTS of cool things you can add for looks and function if you know or see what you want and grab it at the junk yard. But there are a few performance tweaks...

- If you have no intentions of any independent fuel or ignition systems, a computer (PCM) from a 2002-2004 300M SPECIAL will give you a real nice edge. More aggressive tune, and the transmission shifts quicker and firmer.

- Change your transmission gears to the one found in any LH car that has a 2.7, or find a 300M Special. You can access the gears from the panel at the rear of the transmission once you remove the mount. Easy easy easy job. For the cost and work involved, this offers the BEST difference in power. If you got money to throw away, find a set out of a Prowler, or get a set of Prowler Pro Gears.

- Police/Special Sway bars, they offer a 35% gain in cornering performance, also the springs are stiffer.

Now for the real stuff...

- You can build a stroker out of your 3.5... Would require you to get a 4L crank, pistons, rods, bearings/rings. Appropriate machine work and you got a real nice torque difference.

- Turbo it... Which is my end goal.

- Inerita Performance offers a few goodies for our motors... From three stages of cams, to port and polished heads that optionally offer bigger valves.

- Bore out the throttle body (about $100).

- Intake Spacer kit was mentioned, something worth adding.

- Port and polish your lower intake manifold

- Can try a LX intake manifold swap

- High stall torque converter

- Limited slip differential

I'll go on, but your bank account is likely empty.
Damn right I have no money. I intend on going to Fredonia in NY, the biggest party school in the state, so hopefully I can make some money racing while I'm there and upgrade some more to win more. Plus there's a racing group in my area code that's pretty big so I'm trying to get in to that.
 

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Damn right I have no money. I intend on going to Fredonia in NY, the biggest party school in the state, so hopefully I can make some money racing while I'm there and upgrade some more to win more. Plus there's a racing group in my area code that's pretty big so I'm trying to get in to that.
I'm always interested to read how folks are modifying their Treps but your plan is to street race a Trep and make money at it? Who/What are you going to race?
 

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Discussion Starter #13 (Edited)
I'm always interested to read how folks are modifying their Treps but your plan is to street race a Trep and make money at it? Who/What are you going to race?
I'm going to be racing mainly people in my area code, there's a group we have for it with about 500 people in it. We're most of going to a dyno to see what we all have. I'm using it before upgrades to show I have about 240 hp, then afterwards it'll be much higher. Of course I'll reuse the dyno to figure out new power, but it won't be through the group;)
Edit: where I live it's not insanely popular, it's mainly ricers with /okay/ cars, it's not hard to win here
 

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I'm going to be racing mainly people in my area code, there's a group we have for it with about 500 people in it. We're most of going to a dyno to see what we all have. I'm using it before upgrades to show I have about 240 hp, then afterwards it'll be much higher. Of course I'll reuse the dyno to figure out new power, but it won't be through the group;)
Edit: where I live it's not insanely popular, it's mainly ricers with /okay/ cars, it's not hard to win here
It'll show you have a lot less to the wheels sadly. I don't know if racing is going to benefit you financially like you planned. These cars have balls, but it's a full size heavy sedan and that'll lug you down terribly.
 

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Discussion Starter #15
It'll show you have a lot less to the wheels sadly. I don't know if racing is going to benefit you financially like you planned. These cars have balls, but it's a full size heavy sedan and that'll lug you down terribly.
It's big but I'm looking to trim weight off big time. How yet I don't know. I'm thinking of getting painted black and switching trunk and hood to carbon fiber. I haven't looked in to it much yet but ideally that's what I'd like to do
 

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Is the only way to get the whp up closer to the hp to upgrade? Or would cleaning things like lower exh mani help at all?
Not sure what you're asking but. Your HP at the wheels will never match the HP at the crank. You will always loose HP through the trans, differential, etc....
 

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You'd need to upgrade to increase crank hp which after going through trans, diff, etc would come out with probably 67% of that going to the wheels due to trans, diff, etc causing parasitic losses. Increasing crank hp would involve any of the mods stated above except for the gears due to that just changing the curve.
 
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