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Exhaust Manifold Options

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M_Pied_Lourd

M_Pied_Lourd

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OK, looking at my options for exhaust manifolds now....

Would be interested in hearing opinions on the following.

Parts car came with the stock exhaust manifold. Race car came with a 4 into 1 header.

I am assuming that while the header might help the car to breath better, it will also lead to higher under bonnet temps and potential carb/fuel problems. I don't really want to go to the expense to ceramic coat the header althought I could invest in one of the carb heat sheilds.....

The plus for the stock exhaust manifold is that I have a complete falcon ss sytem in good condition from the parts car as well. If I was to go the header route, I would probably modify the falcon exhaust and only use one muffler (larger) with a straight pipe out to the back. Right now the race car has a straight through exhaust that has a small "cherry bomb" style "muffler" just behind the X section. I think that this will be too loud for street driving and haven't considered it as an option.

Are there enough positives to go with the header vs a stock system other than the bling factor.

Cheers
M.Pied Lourd
 
There is an asbestos type wrap you could put on the headers to help with the heat. Not as pretty as ceramic, but effective. Speed shops/specialty outlets are the source.

Add one more cherry bomb to quieten the exhaust note.
 
I've used header wrap before with good results, you can touch the pipes directly after use no problem.
In a wet climate they will accelerate the rust issue on headers.
How much of an improvement (has anyone dynoed) is the header change from stock?
Approx, I know there are a lot of variables if other things have been done but ballpark HP figure.
 
Depends on your goals, IMO. The header will provide a significant performance advantage over the stock TR3 manifold even without optimizing the mixture & timing to match. I didn't have any problems with heat, either.

But they are shorter lived and not as tolerant of abuse as the cast iron; hence less reliable overall.
 
Something for the future during a rebuild, I only have 13k on a redone moter and it runs too good to mess with it now.
I've always heard that headwork pays the best dividends money to hp tho.
I don't have heat problems in 110 degree Az heat either except maybe one more turn over on crank from some evap after a long drive. No shields.
 
Hi guys, thanks for the reponses so far. The car did actually come with a roll of header wrap, pretty ugly looking beige stuff. I might go up to my local performance shop and check out what they have up there.

Randall,prb, are you running with a header on yours then?

Cheers,
M. Pied Lourd
 
the race header will most likely require a hotter cam and head work to work properly and will most likely work from 3000 or 4000 rpm and up. So it depends on the tune of your engine and it depends on the design of the header-pipe diameters and lengths. You can end up with a big flat spot around 3000-4000 with a 4-1 header if it is not designed correctly for YOUR engine. A 4-2-1 header, if designed correctly, will work better with a street engine. On an inline 4 cylinder engine, it is importent to have exactly equal length tubes on the header (if you want to make the most power). V8 engines are totally different since you do not have even firing on one side of the engine unless it is a 180 degree crankshaft (ferrari). A 4-2-1 header will have cylinders 1&4 paired and 2&3 paired for equal pulses.
Rob
 
Hi Rob,

Don't have too much info on the engine but I know that the cam is stock, it has the larger 87.5 mm pistons, balanced crankshaft, rods and pistons, and the head has been milled to increase compression ratio from (and this is what the PO says)"100 lbs stock to 125 lbs"

Here is a shot of the header that was on the race car.

P1040037.jpg


P1050085.jpg


Cheers,
M. Pied Lourd
 
Use that gear reduction starter also. Great upgrade over the stock unit.

Also, going from 100HP to 125HP would indicate to me that the cam is not stock.
 
Hi Art,

I am sure that the PO indicated it was a stock cam...I believe the reason he mentioned was because he preferred the low end torque of the stock cam vs another profile (I could be wrong as I had this discussion over a year ago). The notes I have on the car do not indicate anything other than the stock cam. Also, the note says "compression raised from 100 lbs stock to 125 lbs" not hp.

Cheers,
M. Pied Lourd
 
The choice of using a header is also decided by the intake manifold. On the BRG TR3A I did, the use of the header exhaust meant that the intake manifold used had to be the improved one from a TR4A. The original intake manifold may not fit when using a 4-branch header. But this puts the original TR3A SU carbs (H6) further out too far and you may need to massage the sheetmetal bodywork for them to fit with original SU air filters. That's why the TR4A has the shorter SU carbs - the HS6 where S stands for "short".

We modified some thin air filters and moved the securing holes to be off the centerline as these holes are on the TR3A air filters.
 

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M_Pied_Lourd said:
Randall,prb, are you running with a header on yours then?
Click to expand...
That was 3 TRs back for me. Had a header that looked exactly like yours (cheapo from Warshawski's aka JC Whitney in Chicago) with 87mm liners (also JCW) plus a "3/4 race" cam from Bap-Geon. Ran like a scalded rabbit. The car was junk, but I sure wish I had that motor back.

To that end, I have a set of 89mm liners and a 4-2-1 header on the shelf, waiting for my Larry Young cam to come in. IOW I hope to go back to running a header Real Soon Now (Well, actually, I'll probably get a Stag back on the road first, unless the motor currently in the TR3 blows up. Maybe by 2015
grin.gif
)
 
No header on my Tr3...maybe when I rebuild.
If you use the header tape it will burn in some...you'll smell it for a few days as it takes a set...normal
 
Thanks for all the responses. So, I think that I will go with the header and will head up to the performance store and buy some wrap for it. I took a look at it tonight and I think I should be able to do a pretty good job of wrapping it.

Don, interesting about the intake manifold. The car came with a set of K and N filters but were not installed on the car....maybe that is why. I will have to check it out when I get the chance. My intakes seem to be multiplying....I have found 5 so far between the two cars and the spares that were given to me.

Cheers,
M. Pied Lourd
 
I have jet coated headers (4-2-1)on my TR-3B going into a Monza exhaust. The car runs great.

The only thing I want to do is make it louder.

What size cheery bomb should I buy?

I think I will remove the Monza and go with a cherry bomb into twin Monza tips.

Does anyone have that type of exhaust on their cars?

Thanks.

Paul
 
I would use a 270 to 280 degree cam with that pipe with a 2 1/8" to 2 1/4" exhaust after the header. twin straight through mufflers (glass packs) will keep the sound reasonable. Twin su's with the tr4a manifold will work well on the street. I would definitely pull the head and cc the chambers so i know exactly what the compression ratio is. If it's above 10:1 you will want a thicker head gasket otherwise you need race gas. One thing i have found is that NOBODY makes an aftermarket header that has true equal length pipes, NOBODY.
M. Pied Lourd, your primaries look like 1 5/8" diameter. How long are they?
rob
 
A.R.E. Heatshields I will be using a heatshield on my TR3a. I beleive (Dan) Tinman58 is using the same on his car with a header. Velocity Stacks might be an option also. A.R.E makes alot of nice parts for our LBC's

Paul
 
Paul
straight through mufflers should always be full pipe size connection with the insides one size larger, so if you exhaust is 2 1/8" the inside of a straight through muffler should be 2 1/4". The longer the muffler the quieter. Mufflers closer to the engine will have more effect than mufflers farther from the engine.
hope this helps.
Rob
 
Let me caution you about my comment on using a thicker head gasket: A thicker head gasket will reduce the efficiency of the combustion chamber since it increases the squish volume(the flat part of the head in the combustion chamber) which reduces the speed which the gas is pushed towards the combustion chamber.
Rob
 
Thanks Rob.

Not sure I understand what you mean by mufflers closer to the engine having more effect.

Does that mean I should put the muffler closer to the engine if I want it to be louder?

Paul
 
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