Bartman Posted June 4, 2005 Share Posted June 4, 2005 Here's a shot of how my car looks now: I've got most everything worked out except for bodywork, paint, and the interior. I have coilovers and I think the car could be lowered a little bit, but the exhaust is already too low. I'm looking for advice as to what to do with my exhaust. I have nice long tube headers and single 3" exhaust (the rear section doesnt fit with my LS1 fuel tank), but I think they sit way too low. The rear of the exhaust would be raised a little when completed, but I'm not sure I want to stick with this system. It seems that a lot of you are looking for long tube headers, but I'm not sure they work for my application. These are great Tri-Y ceramic coated units that Tim240Z made with 1.75" primaries going into 2.25" into 3" collectors. Are these so good that I should just deal with having low clearance, or should I sell the full exhaust system and have one made that will give me more clearance? If I keep the headers, I then need to figure out if I should keep the mid section, or replace from the headers back. Whatever I do, I want to have 2.5" duals out the back (one on either side of my LS1 tank). I already have my FlowTech Afterburners sitting in my garage. BTW - My car will not be a daily driver, but it will be for street use only; so I could give up a couple HP's so that my car can sit lower without scraping the exhaust. Quote Link to comment Share on other sites More sharing options...
Bartman Posted June 7, 2005 Author Share Posted June 7, 2005 No one has any words of advice here? Could anyone tell me about how much horsepower difference there would be between having these long tube headers with a single 3" exhaust compared to block hugger headers with dual 2.5"? My car has an essentially stock 94 LT1 engine. Quote Link to comment Share on other sites More sharing options...
2126 Posted June 7, 2005 Share Posted June 7, 2005 Of course this is just one idea......based on my experience with a very low Z, the biggest problem area is the ground clearance 1/2 way between the front and rear wheels. Driveways and speed bumps tend to get the closest to the under side of the chassis at this point. So as a suggestion, you may consider installing the oval shaped pipes, that are used on corvettes. The side profile on these pipes are much less than a 3" diameter round pipe and provide the same flow. Also, you may consider a side exit exhaust just in front of the rear wheel (like a cup car). Would look similar to the old TransAm cars. Just some food for thought! Quote Link to comment Share on other sites More sharing options...
wheelman Posted June 7, 2005 Share Posted June 7, 2005 Bart, Take this for what it's worth as it's just my opinion but I would go for the extra ground clearance. If your car is to be mostly a street car then you'll undoubtedly drag those headers at some point which could cause all kinds of problems. I also don't think you'll miss the few HP that will disappear by going to the block huggers and 2 1/2 inch setup. Remember this is just my opinion and your mileage may vary. One question though, how far did you set your engine back when you installed it? The reason I'm asking is you might have steering shaft clearance issues depending on where the engine is. I also found that I had to bolt the engine set back plates to the block instead of the spacers to clear my block huggers. I'm guessing you already have things setup this way to clear Tim's headers but it's something to check just in case. Not that it would preclude you from changing to block huggers it just might mean more work if the motor mounts have to be reconfigured to clear. I went with the Headman Tighttube block huggers. I like them but don't have any real history with them yet so I can't comment on whether they have leak problems. The tubes are a bit thinner than I expected but I got the ceramic coated ones for $100.00 off eBay so I'm not complaining. They hug very tighly to the block but also clear the knock sensors. I guess the only real complaint I have so far about them is they don't leave much room for the spark plug wires. If I remember correctly Tim routed them over the top so you shouldn't have any problems with them on your engine. Hope this helps a little. Wheelman Quote Link to comment Share on other sites More sharing options...
Bartman Posted June 7, 2005 Author Share Posted June 7, 2005 I've decided to order a pair of block huggers from ThermalTech and get some extra clearance. So for those of you high horsepower guys that want a killer exhaust setup send me a PM as I will be selling the complete system. According to one source I spoke with long tube headers are better for high revving engines and that the block hugger headers may have higher horsepower at lower RPMs. Either way, I think that for my application I want the extra clearance. Wheelman, My engine is as far back as it would go, and I may need to make adjustments to allow fitment of the block huggers. I also didn't use crossmember spacers, so I may need to install those as well. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted June 7, 2005 Share Posted June 7, 2005 Bart....if you arent going to use those headers, please let me get them back..... BTW.....my car was pretty low and I had no scraping issues. Tim Quote Link to comment Share on other sites More sharing options...
DaleMX Posted June 7, 2005 Share Posted June 7, 2005 Bartman, Longtube headers will have a greater low RPM torque increase as compared to blockhuggers. I think the LT1's like 1 5/8 to 1 3/4 max tubes with 3" collectors. Adjusting the length of the collector will also change the curve. Stepped headers ( 1 3/4 start to 1 7/8 end) dumping to a 3" collector have been very succesfull on the LS1 stuff. Visit "Headers by Ed" web sit for some good header info. Personally on my LS1 I have chosen to to with 2 1/2" duals thru an X pipe going to Sweet thunder mufflers and dumping before the axle. I am going to try to get as much pipe into the tunnel as possible for ground clearance. The Sweet thunders are only 3" total in diamater (kinda loud though!). Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted June 8, 2005 Share Posted June 8, 2005 Bart, I say keep the headers but use oval exhaust tubing to the rear of the Z. As you know, my Z has dual 3" exhaust from the turbos, over the axle and out the rear. My ground clearance is minimal but it is doable because I'm using SPIN-TECH oval exhaust. The 3" tube only takes up 2". Your 2.5" exhaust would probably only take up 1 5/8" if it were ovate. It's a thought. Hanns Quote Link to comment Share on other sites More sharing options...
Bartman Posted June 8, 2005 Author Share Posted June 8, 2005 Bart' date='I say keep the headers but use oval exhaust tubing to the rear of the Z. As you know, my Z has dual 3" exhaust from the turbos, over the axle and out the rear. My ground clearance is minimal but it is doable because I'm using SPIN-TECH oval exhaust. The 3" tube only takes up 2". Your 2.5" exhaust would probably only take up 1 5/8" if it were ovate. It's a thought. Hanns[/quote']From what I've read in other posts, the oval exhaust is pretty expensive. The mufflers aren't a problem because they will be able to tuck up in the rear of the car on either side of the LS1 fuel tank. I think the biggest thing is having the exhaust tucked up a little better like Pete's system http://alteredz.com/exhaust.htm. The only thing I want different from Pete's is the rear part, since I will be able to exit on both sides instead of having both pipes exit on the same side. Quote Link to comment Share on other sites More sharing options...
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