36 replies to this topic

[93hpCRX]

It really looks like a weldable mild steel header would be better in the long run anyways, ive read a frew articles that all point towards reliability and durability coming from a thicker mild steel, rather than stainless. As some know, stainless as it gets hot actually looses its stregth and eventually, especially on a header, the stainless can turn white and crack. Yes the DIY kit does sound like something i may be interested in. Just to straighten a few things out, i wont be making the bends myself, they will mandrell bends that you can buy that are fairly thick. I will be installing one my car in the spring but i really dont see myself going to a dyno untill the following year. 93 hp crx, im interested in sending one to you as soon as your ready to do the dyno. Till then il be making a prototype and il post the finished product then.

Turbo manifolds would be easy, i would only make them to a T4/T3 design, because its now the most common turbo out there and most likely be well suited to our motors.

Im actually just waiting on the sensor for my wideband, then ill be able to find a local dyno, ive got one around here for $75 30 minutes. 3 pulls pretty much. Ill keep ya update on what my plans are.

Thanks
Dustin

[chedda_j]

The is what im going to build minus the lower pipe.

Im going to start on it in two weeks.

[JEA86]

good deal! cant wait to see final results

[hondaguy72]

Kamikaze style! Should work well with our engines. I'm trying out a FI induction setup, but if I go back to n/a that is what I would want. What size primaries were you considering?

[chedda_j]

The main ID diameter on exhaust side is 1.5" x 1". Because the ports are ovaled, I plan on using 1.5" ID x .125. If there are any clearance issues then I will oval the pipes in order to make sure the bolts are accessable. The 4-1 collector will most likely be handmade myself or ordered through my local lordco supplier. The oulet is planned to be 2.25". You may say thats not enough flow but as compared to the 1.75" original collector, your looking at 28% increase. In order to to create the proper header dynamics, i wont go larger than that on a N/A 1.5. You will effectively destroy how the header will work with anything larger than that and if you were to gain any power at all it would only be at very high rpms. So to make the header work properly il be using 1.5 then to 2.25 for maximum power between the 2.5-6 rpm range. Remeber too much flow can make you loose power, there is a certain amount of back pressure needed to actually make a header work right.

I forget who said it best on this site but its like putting your finger over a garden hose: too much and you restrict, too little and you just trickle out.

After the manfold il recomend 2.5" all the way back.

After thinking about my statement you may see my collector at 2.5. But untill my designing is complete i wont know for sure.

[1986_crx_si]

Sound like you know your stuff Chedda. I'm VERY interested.

-Aaron

[chedda_j]

I know enough, now that I've done some more research I'll be going with a 2.25 collector hand made by myslef. II ordered the bends today, 1.5" I'd 3" rad bends, should be here in a week or so hopefully. From there I'll be making the manifold plates and taking a 1/4" plate to make a jig. From there I will be making the manifold plates from 1/4" plate, machining them flat, then install them on the jig and make the rest. I'll have to weld a bung on for the o2 sensor. I will include a bung plug for you carbed guys.

[Qronik]

I think my HF is in love ....

Thanks Chedda !

[Buford]

You really have to do your homework on the primary and secondary pipe lengths and diameters. There are some good online calculators out there but they only get you in the ball park. The rest must be developed on a Dyno.

Now the hard part. What works well for a stock/mild modded street car will not work well for a full race modded track car. Same the other way around.

You have to know what you are building to.

[wyatt89]

ballpark estimate on price?

[93hpCRX]

Ive got a full 2.5"from header back, ill be doing 3 dyno runs come mid January. Ill post it up and await Mr.Chedda. I hope its everything you want and then some, I love the design of that header. It should be alot better than the pacesetter header i have now. clearance and flow.

[chedda_j]

Between me and you I just need to know a few things, when I make this header, theres a good chance that its not going to match up to your exhaust right now because my header isnt the same as the pace setter obviously. Second of all, the header that im selling isnt going to be a direct bolt on for people who just want to upgrade the header without doing any work to the rest of the exhaust. This is quite obvious, but the stock exhaust will be too restrictive to see any performance gains from the header im building. To get maximum performance you will need a good Catylitic Converter, and 2 1/2" smooth bend exhaust, preferably with a good flow through muffler. As soon as spring comes around you may see me sell full mandrel bent exhaust kits for these cars in the neighbour hood of 600 or 800 including the header.

Ive done the research and looked into the design of a good header for our cars, short runners, smooth bends, and a good collector after about 12" of tubing will give the maximum performance. Other designs that would work good are a 4 - 2 - 1 but in order to do so the header would have to be longer and from that you may loose some performance. In larger series headers for motors such as the 2.2, the best headers are 4 - 2 - 1 but are long, they go from 1.5" then to 2" then to 2.5" then to 3" exhaust. In our case we dont need anything that flows nearly that much.

For you guys that are building race motors with the 1.5 si, its going to be hard to get 150 hp, the header built by me will more than suffice to your needs. Anything more than that you are looking at a turbo and in that case, my header cant be used. Turbo headers are typicaly ram horn style and there wont be that much of a market for a 1.5 turbo car because time spend can be spent on a b series swap.

The idea for this header is for guys with the 1.5 that are still looking for some performance gains. There is no market for performance stuff for these cars so for me to spend hundreds of dollars on dyno runs is rediculas. In the long run i may sell a wopping 15 headers in 5 years, now where does that get me when i have to spend *x* amount of dollars on research for the "perfect" length of header. So in order for this to be worth my time at all and maybe make a tiny bit of money im going to essentially copy the best design from other honda motors to build a good header for these cars. The have done the research, they know that these headers work, and infact il know it will work just as well. I really hope i can get this header for sale as soon as possible so you guys can get these little cars to go just a little faster, because thats what its all about. I work for you guys because i love all the guys on this site and ive always loved these cars. I have alot of passion for this site and these cars, i hope that i can always offer you my services aslong as this community is still alive.


Im gonna throw out a number for the header and I hope i can do them for $200 but we will have to wait and see.

[1986_crx_si]

Chedda,

$200 for a header is not unreasonable. You have obviously spend a great deal of time and effort on this, and I doubt anyone would have a problem with that price, seeing as the Hedman Chikara is $150 new.

I'm sure the folks here (myself included) will have no problem dishing out an extra couple of bucks knowing that they are getting something Chedda_J quality, and not some mass produced hunk of metal that claims performance.

Not to thread jack, but you should consider producing a 1 or 2 piece mandrel bend intake to compliment the header you are making (and the possible exhaust kit.) Heck, why not make a mild performance cam for us, and you can have a 'Chedda_J's Stage 1 Engine Upgrade Kit' - Intake, header, exhaust, cam
and 'Chedda_J's Stage 1 Suspension Kit'- Panhard bar, shift knob, shifter

Just an idea,

-Aaron D

[chedda_j]

I have thought of making a CAI for these cars but for me to build one would mean that i would need access to an SI for atleast a day to get some dimensions.

The idea I have for my buisness is to slowly integrate all the parts from this site into a ready to order company. I started with the shifters, then the PHB's and now headers. Hopefully in the future I can offer more products, you will deffinetly see strut bars from me in the future and definetly some more exhaust products.

[wyatt89]

im def interested, i was gonna get a hedman, but ill wait.