LT4 Headers worth it on a fairly stock LT4?

[megatron]

Hi,

Wanted to obtain some advice from the experts here. I have a fairly stock LT4 (Corsa and K&N) and am interested in adding EM LT Headers for extra power.

Are headers worth the price for an essentially stock LT4 engine? My car dynoed at 300.35RWHP with the aforementioned mods. The headers would cost me about $1500 installed. Note: Random Flow Cats would be installed

Also, how would the sound change with the headers? I don't want the car to become too loud. Add in ther fact that I have the Corsa and I am concerned about it being too loud.

Anyone have a soundclip?

Thanks in advance for the responses.

 

[Skyguy007]

From all I've read, the LT headers, Random cats, and Corsa exhaust should make a significant improvement in your LT-4's torque over a wide range. I don't think the interior noise will change much until you really step in the gas.

I'd like to know your part numbers and your impressions on the fit and finish once you get everything up and running after the switch. My GS could use the improvement too.

 

[Greg@NASA]

I recommend doing the header mod.My LT-4 is exactly the same (K&N, Corsa) and dyno'd 300 rwhp before the TPi long tubes were installed.

Post installation was 311 rwhp, and 318 torque, the torque curve is incredibly flat.

Noise is unchanged untill you really stand on it--when the car gets up around 4k rpm it really sings.

Bottom line---2 grand well spent. ($500 was for lifetime Lt-1 edit)

Greg

 

[redvette6spd]

Headers are a great mod Thay will make your car sound like it is suposed to and give you better performance. If you are planing other mods thay will only be improved by having LT headers. I have LT headers Corsa and a LT4 Hot Cam thease three mods combined put me over 400hp at the crank. Oh a good tune also.

 

[wx briefer]

My signature shows the mods. Put the headers on ASAP. My vette is quiet but sounds 'Nascar like' when one's foot is in it according to a friend that is a fan of the 'round, left turn only circuit'.

 

[Fick]

I recommend doing the header mod.My LT-4 is exactly the same (K&N, Corsa) and dyno'd 300 rwhp before the TPi long tubes were installed.

Post installation was 311 rwhp, and 318 torque, the torque curve is incredibly flat.

Noise is unchanged untill you really stand on it--when the car gets up around 4k rpm it really sings.

Bottom line---2 grand well spent. ($500 was for lifetime Lt-1 edit)

Greg

I also have an LT4 with K&N,Corsa and am considering the long tube headers; but if I understand your post your 2K investment netted an 11 HP gain. I don't think the results would be worth it to me. Is their something I'm not understanding? I know the headers would help a lot with the Hot Cam but I don't plan on doing the cam.

 

[megatron]

I also have an LT4 with K&N,Corsa and am considering the long tube headers; but if I understand your post your 2K investment netted an 11 HP gain. I don't think the results would be worth it to me. Is their something I'm not understanding? I know the headers would help a lot with the Hot Cam but I don't plan on doing the cam.

I think it was 11 RWHP. If I am not mistaken, that would be about 13 horsepower? Not a big difference. I think the differnece lies int he torque curve. For instance, my LT4 makes 300RWHP at 5600 rpm. When are you going to drive at 5600 rpm? Not all the time. I think the headers bring some low end torque. Is this correct?

 

[Greg@NASA]

Yeah, the crank HP gain is around 13 , the torque is the real difference.LT-4's breathe really well as is......the long tubes are the foundation for further work ("hot cam" and larger TB).Plus they are real beauties.


Greg

 

[LT4BUD]

I think the differnece lies int he torque curve. For instance, my LT4 makes 300RWHP at 5600 rpm. When are you going to drive at 5600 rpm? Not all the time. I think the headers bring some low end torque. Is this correct?

1) Usually a stock or near stock LT4 peaks in hp at 5800.........if you are racing a LT4 you want to shift right at red line of 6300.......

2) Yes, the LT headers increase torque pretty much across the entire rpm range, including low end.....

 

[Edmond]

Yes, the LT headers increase torque pretty much across the entire rpm range, including low end.....

Ah, so the power increase comes in at a lower, and usually more usable, RPM!

 

[Greg@NASA]

Ah, so the power increase comes in at a lower, and usually more usable, RPM!

Looking at my dyno graph,the torque at 2300 rpm is well over 300 ft/lb, and stays remarkably flat through 5300 rpm--where it meets the HP curve (which is now flat till rev limiter).


Greg

 

[nearmiss]

Does anyone know if you can put long tube headers on a car in California and be legal? I think you have to relocate the cats and I'm not sure if it will pass emissions inspection once that is done.

 

[Edmond]

I don't believe that long tube headers are CARB approved. I don't think it would pass the visual inspection.

 

[Vettelt193]

I think technically you aren't supposed to replace working emissions equipment... meaning, unless your cats are bad you can't change them out. I could be wrong though.


IMO 1,500 - 2,000 isn't worth under 15 HP. You can throw a cam in there and get a lot more power for much less.

 

[wx briefer]

"Headers worth it on a fairly stock LT4?"


Yep!

 

[96vetteLT4]

I'm having a hard time believing a 2K investment is worth a possible 9 to 11 h.p. increase. There are a lot of other upgrades that would give you the same amount of H.P. and torque for a lot less money. The Biggest fact is that the stock LT4 exhaust is known thoughout the industry to be one of the best flowing exhaust ever produced. I have seen dyno inprovements rangeing from +3 h.p. to 12h.p. Now if you devide the cost into the h.p. it seems that you're paying a lot for a little including the pain and noice of the exhaust hookup. For the same price of headers you could install a new HOT cam or rear gear set and make more power and a better E.T.....just my opinion though................

 

[Kevin Doyle]

Headers

I imagine that headers are alot better quality then when I was a kid but they were always a pain leaks,loose,rust.I will stick with my stock exhaust and aftermarket cat-back power effects system.Low maintenance sounds great.I try to do everything I can myself,but the less I have to slide underneath the better.Not enough hp gain for money.(imho)Thanks Kevin.

 

[megatron]

I'm having a hard time believing a 2K investment is worth a possible 9 to 11 h.p. increase. There are a lot of other upgrades that would give you the same amount of H.P. and torque for a lot less money. The Biggest fact is that the stock LT4 exhaust is known thoughout the industry to be one of the best flowing exhaust ever produced. I have seen dyno inprovements rangeing from +3 h.p. to 12h.p. Now if you devide the cost into the h.p. it seems that you're paying a lot for a little including the pain and noice of the exhaust hookup. For the same price of headers you could install a new HOT cam or rear gear set and make more power and a better E.T.....just my opinion though................

I used to think the same thing, until I realized where in the RPM range the HP/Torque came. Sure at the peak (4800 RPM), the peak may be 11hp, but it is lower in the RPM range where the difference is more significant. For instance, let's say that my car makes 230RWHP at 4000 rpm. With headers, (using a car with the exact same setup as mine -except the headers of course), it should make about 250RWHP at the same RPM, which is a 20HP gain.

In other words, it gives you more power on the low end by flattening the torque and HP curve.