Blaine Sellie

I am considering a header system for my 1988 Turbo Cab and need some advice. The B & B or GHL are nice, but I am wondering if an equal length header system may provide better performance and the exhaust note I am looking for.

I installed the Fabspeed with my stock system and realized a nice performance gain, but was not a big fan of the deep burble sound which reminded me of my high school car.

I would like a nice tight sounding exhaust and wonder if the equal length header combined with close to stock muffler, maybe the euro, would provide a good tone.

I think Brent 930 has tried most combos and could comment as well.

Blaine

Blaine Sellie

Would this be a good option?

Brent 930

I have the GHL with dual Fabspeed and like the sound of the muffler. If you don't like the sound try the single tip GHL one. For a CIS motor the B&B and GHL are fine. Even primaries are better but it won't be noticeable with CIS IMO. Then you have to make changes in order to get heat if that is something you want. If your doing a long track staying on boost for a while then it's a good idea so the heat is even. If you put a close to stock muffler on any header you will defeat the purpose. My next headers will be 1 5/8" even primaries from Marco or Holcomb when mine go with the modified heating system from Proto.

Blaine Sellie

I can appreciate the fact that there wont be much of a performance gain, but will there be a distiguishable change in the sound with the equal length?

Blaine

Brent 930

I would think the muffler choice would be the determining factor not the headers. I'm no expert and can't say for sure since I haven't tried it. Some of the things I say is both experience and theory.

PorschePhD

There is some sound difference but the that should not be why you buy the headers. The headers in the picture are 1 3/4 which is too large. for a 930 engine. You will loose most of your lower end. The equal length will add HP and the burns collectors work like a charm. Then again there is about 1500 in collectors there. The equal length will cause the low end to suffer because it is a longer route to the turbo and velocity is slowed down. If you want to reduce spool then 1 5/8 short tube headers are the way to go. The collectors are not critical until 500HP +

Blaine Sellie

I would definately go with the 1 5/8" if I did decide to go the header route. How much horsepower would one gain over the GHL or B&B type system?

On the muffler front, would the RUF or Borla give less burble on decel?

Blaine

m42racer

Blaine,

I would suggest you call some Engine builders and ask them. Most of the systems out there are designed the way they are because of price not performance. Another The important area when buying an Exhaust system for a Turbo application has not been discussed yet. If you buy one of the pre made catalog types, they are typically made from 304S. This material is not a good choice for Turbo applications, hence the reason these systems crack so often. 321S is the beeter choice, but up goes the price.

I don't agree with the statement about the use of a merged collector. The advantages that a collector gives has nothing to do with engine HP. If fact, do not buy a system because it gains HP. Buy a system because it gains throttle response. Further, that is the reason why most of the systems out there designed and built by those who know, are of a stepped design. To allow for Reponse, Torque and not limiting upper end RPM's with back pressure. They all will have merged collector.

PorschePhD

You are correct, headers do not add HP. Not unless the original exhaust was restrictive which most aren't. However, the collector certainly has proven to be a limiting factor on cars we have pushed beyond 500+. If you read my post again you will see that I state there is little difference to a car under 500HP.The collector used in a majority of the aftermarket off the shelf headers is not good enough to flow properly and starts to bottle neck around this mark. Hence you loose power. Take two of them at 280HP and the collector will not make a difference. I will be more than happy to provide dynos to you if you would like.

Bottom line is a set of equal length headers for a turbo will shift the band to far up. There is no way around it. While the cheaper headers out there may not be the best for a majority of the applications they do what they need to. They increase velocity to the turbo. To build a quality header is not cheap, one the price of SS has gone up and 321 is through the roof and two to use quality collectors is not cheap.

The headers in the picture are designed to put up with a motor that is going to be a drag setup. It will be somewhere in the neighborhood of 700+ to the wheels. I should know, I am building it. I would not recommend this setup for a CIS street car.

PorschePhD

Actually let me correct myself. I would use a set of short tube primaries in equal length. But with the position of collector it would make it hard to pull off unless you did another type of collector. Could be done and I haven't really seen a set of short tube equal length with quality collectors.

m42racer

There out there, been done many times. Quality Engine Builders use and supply them everytime. These are Engine Builders not assemblers of catalog parts. The problem here is always the cost. These types are custom built for the specfic application.

As for the shift in power if the pipes are equal length, that statement is a little misleading. The power band is affected by length, so if the Porsche Primaries are shortened and of equal length then what you say is correct. This also is highly affected by the length of the secondary leg. In most cases, making the primaries equal length is never done due to the cost and the builder of the Exhaust system not wishing to take the time.

As for the system in the picture, looks like it has a collector, short primaries, but a long secondary. This design is contary to most typical exhaust system designs. Typically you have short primaries, collector of designed length and a short secondary, when higher RPM levels are required. When the btm end and throttle response is required, the primary lengths are increased, along with a collector length to match and a longer secondary. Not sure why you would want something like this for Drag Racing. I would expect a very short primary system of around 1 7/8" , a very short collector and a secondary length of even shorter length. Lets face it, your not needing any reponse from the turbo when leaving the Line. I would expect your at full boost with the antilag system in full gear. Still, every engine is different, and application requires or is thought to require something different. Something I do not understand about the system in the picture is the use of 1 wastegate. Most of the systems I have seen where they have been designed, have included 2 Wastegates, even with 1 Turbocharger, It makes sense, opening time to control exhaust pressure is shorter, giving quicker response times. Nothing new.

As for the power levels under 500 Hp not needing a collector, just don't understand what you mean. If the collector makes no difference, then there must be many other things wrong. A collector helps scavanage the exhaust from the port. If you see no advantage from this, then I expect the problem is in the Heads, Cam design and centerlines, and what ever you have run in the way of primaries. Every exhaust I have seen with a collector has made a difference regardless of what was in front of it.

BTW, I understand you built that engine which was pictured here sometime ago. Is this the one for the Ohio customer which Endless are installing? I heard about that engine.

PorschePhD

About two years ago I went through several sets of headers in different designs. While in theory that is great and what the data showed on a stock application was the power band moved up the scale and the upper in HP continued to climbed off the scale. Now obviously that within itself also will be misleading because as you know as well as I do cams, head design, turbo etc will also effect the end result. Every set we tested with collector or not under the 500 mark showed little change. The short primary and the longer secondary always produced a lower power band. The other thing was with one set that was tested with 1 3/4 we lost torque across the band. On a separate occasion in an EFI setup the car was running a tad over 500HP and running X set of headers when switched to a set with a triangular collector verses a flat collector the car picked up HP. Once again that could all change based on the rest of the design. I had put together a spreadsheet. I could email it over to you if you would like it for your data.

For the application that Blaine is talking about neither would make enough of a difference to justify a 2K difference. At least as a customer asking me I could not recommend to him that the cost would be justifiable. I know my examples are probably not the most scientific in the world but it was a real world comparison to gain some data into what we would really see- theory Vs. actual application.

Agreed on the wastegate issue. This continues to be a design that should be changed. Yet everyone wants to continue to use the single wastegate design. I agree that a dual wastegate or some other design or at least angle into the system is needed. The issue of overshoot will remain until this is changed. Not my headers so I didn't have any say.

m42racer

There is a real need for a quality set of pipes that work for these engines. The difference between the sort you buy in a catalog and the sort designed, is huge. Its a shame most have never experienced it. I know I experienced the repairs needed (many times) with the catalog types.

Kevin

Blaine

With the cars in your collection, you can afford to purchase a set of custom headers.. Well is that a good choice for you? Are you setting your car up for the street or PIR.. If cost is no issue, then have a set of short length primary headers made, with the collector of your choice. I like Burns Stainless units at $350 each.. If you decide to go to equal length header, you will lose you bottem end and shift the curve up the RPM ladder.. Ask Don Enderline....

A little wisdom, buy a set of inexpensive B & B's or GHL's and get your car set up.. Another point, your stock CIS heads along with the CIS pancake manifold are a restriction, that will not fully utilize the custom headers..

M42Racer.. You are making all these claims for Quality Engine builders, (who, and where are they, why aren't they on this board) most people on this board, are building engines in there own garage, and or having board sponsers build them.. Are you willing to race your car, and put up some numbers, where are your dyno sheets, I want to see the torque curve....?? The point that I trying to prove here is, most of us want practical working solutions and upgrades for there car... Why don't you step up and build that engineering marvel engine, that you've been recommending for all of us for the last 2 years..

m42racer

I did build it, and posted the pics.