Installed a 408, now what?
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Joined: Aug 2006
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Installed a 408, now what?
I don't exactly have unlimited funds so Im trying to decide where to put my money next. I installed a new TSP 408 with 237cc heads and custom Ed Curtis cam in my 98 coupe. The car already has a built transmission and rear end but stock exhaust, stock converter and a 75mm FAST intake. I'm planning on upgrading the intake, exhaust, and converter but can't do them all at once; in fact it might be a while before its all done. Just interested to see what everyone thinks I should do first. I'm leaning towards a converter because it pushes thru the brakes at about 1600 rpm and seems to bog down a bit. Goal is 1/4 mile times and for now I'm staying NA.
Melting Slicks
Joined: Jul 2004
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From: orlando florida
St. Jude Donor '15
Converter first. Not fun trying to sit at a light and keep from creeping into the guy in front of you. Of course you can just pop it into neutral.
Plus launching will be slow at the track.
Plus launching will be slow at the track.
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I did take the car to the track. It was pretty comical because I had a wheel speed sensor in an error state that was causing traction control to be stuck on, also the afr was 11.5:1. I've fixed both of those since then but that time at the track it went 2.1 60', then spun once it gone done doing it's traction control garbage, then ran a 12.3 @ 119. Obviously I'm not too happy with that but all things considered it's not a big surprise. Since then I have raced some people that run solid 11s consistently and hung with them just fine but, again, not happy with this car only running mid to high 11s. I have noticed from day 1 that the converter is WAY too tight (I have no reason to believe it's anything other than stock). I'm planning on getting a 3400-3800 FTI lock up converter, I had one in my 98 Camaro and loved it. Just wasn't sure whether to do that first or do exhaust. As far as exhaust goes I haven't really done any research on what to buy but I plan on doing the full system probably starting with headers and X-pipe then mufflers and tail pipes afterwards. I can't help but also wonder how much the 75mm tb is holding me back.
AMP Racing
Joined: Aug 2006
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From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
1) Converter - 3600 or so.
2) Exhaust - used = cheap
3) Intake - FAST 102 with an LS2 TB
I bet it has a ton of torque. crazy fun on the street...
2) Exhaust - used = cheap
3) Intake - FAST 102 with an LS2 TB
I bet it has a ton of torque. crazy fun on the street...
Race Director
Joined: Sep 2005
Posts: 11,060
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From: Pasco WA
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Safety Car
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From: Vancouver Washington
Except - My 408 showed about a 7 to 12% restriction on an LS2 TB and a Nick Williams 102 solved that.
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If I do go FI it will be a while. I want to "finish" the NA setup and see where I am with it. I'd like to be high 10s and still have the car reliable, streetable and comfortable as the weekend driver that it is. If I get to that point I may not ever care about FI because it's not really a drag race car. So for that reason I do plan on going with whatever intake and TB works best. Also I have a nitrous kit I could put on it if I really need to shut anyone up. I'm planning on ordering an FTI 3600 stall lock-up converter this winter and hopefully the exhaust in the spring so that I am ready to put down some decent times next year.