Pros and Cons of these headers and muffler setup from Kerry Hunter?

anyone.........anyone.......Bueller?

I can't comment on the header. However, I've used Supertrapp mufflers on a few bikes, and I've read a good number of objective reviews and dyno tests of them.

They're crap! By the time you have enough disks in the things to flow well, the difference in noise between discs and nothing at all is almost nil. Remove enough discs to make them civil, and they flow very badly indeed.

People talk about "more midrange" when you remove discs, but I have yet to see a single dyno chart to back this up on any engine, car or bike. All they end up doing is cutting power on top, which often FEELS like it's adding power down low. My butt dyno has been fooled this way plenty of times.

Meanwhile, there are other mufflers out there that both flow well AND provide a civil level of noise. I have seen tests where a purpose-designed muffler (for a particular engine) made less noise AND more power than a completely open Supertrapp. I'll see if I can dig up some actual numbers for you (not on a 914 engine, however).

Lots of people like them, but I've always found them noisy. They're really popular with the off-road crowd because the discs do a good job as a spark-arrester.

If Jake doesn't answer this, go over to STF and ask him this directly. I'm pretty sure he's tested them.

Supertrapps also look damn cool when you put a spark-plug in the muffler to a switch and run your carbs super-rich

I used them for years, when the car went to a full track car I did not run any disks.
call Kerry and ask him if you have any questions

http://www.kerryhunterenterprise.com/914-4.htm

I run the full KH exhaust and supertrap. Had to fabricate a mount for the muffler, but that was no biggie. Install went fine, no issues. High points: I like the sound w/the trap, less weight, much easier to work on the underside of the car. Low points: well, duh, no heat, and the KH system comes with just a flash coat of paint, which burns off in stinky fashion, then they start to rust. KH recomends using high temp BBQ paint(!!!), or sending out for high temp coating. They are a budget guys header. Part of the reason I did them was the Grassroots 914 project and testing showed them to make more power that the stock system, save weight, and leave some green in the wallet.

This is my second full race season using the KH headers on my 2.0 4 full vintage race car. These headers are designed more for the budget racer and seem to do the job. Although installation is a PIA without stub pipes and you should use BBQ paint to keep from rusting. I run a completely open SuperTrap which is mega loud. You can also buy the mounting bracket from KH. I had no problems with shipping or fast delivery. Decent guy to deal with.

GB

Stay away from Supertrapps...

Biggest power robbing set up I have ever tested! When they are not too restrictive they are too loud.

Jake

In your testing (on the A-1 and others), you came up with a 2.5" (or 3") Magnaflow as the best. Could you give more details on the can? Oval? Round? 5x8, 5x11?

Thanks

I have supercraps that I only use when I need to attenuate the noise..

I havent used it but Tangerine Racings headers, with the Phase 9 style muffler seems like the shizzle.. and then you can add a quite can for tracks like Lime Rock..

Chris Foley>> Tangerine Racing>> headers=good stuff

I just bought a used KH header set with Supertrapp for my 2.0 with euro p&c's, light flywheel, stock FI. If not Supertrapp, what should I put on the end for best performance?

Jim, I'm listening........

Hey guys, what other options are there for use behind the KH headers other than super trapp?

QUOTE (Porsche Rescue @ Apr 30 2005, 10:34 AM)

Hey guys, what other options are there for use behind the KH headers other than super trapp?

A carbon fiber suzuki hyabusa aftermarket can-----will flow all you can possibly put through it--and only about 250 bucks--sounds really cool too..

There are lots and lots of mufflers in all shapes and sizes and sound levels. Find a good custom exhaust shop and talk to them about it. It can be surprisingly inexpensive to have something custom fabricated.

The bike "mufflers" will be pretty loud.

Can I use the Bursch muffler I now have on the car? Will it be better than the super trapp? It is a dedicated autocross/DE car.

I've got that set up. No problems never been on a dino but if Jake says the Stupid Trapp sucks it sucks & I would be interested in an alternative muffler. BTW it is kind of loud.
E

I've raced for years using Kerry's exhaust and a supertrapp without discs...they're pretty loud without them, and restrictive with them.

I have one of Chris Foley's exhausts that I tried to get on the motor yesterday but it wouldn't fit...the motor is 18mm narrower than stock and it just wouldn't line up so I put Kerry's back on for this weekend.

I'm doing another motor with more HP that's closer to the stock width that I intend on using Chris' system on. I'm looking forward to trying Chris' pipe and seeing what the difference is.

Nothing for the 914 has touched Chris' system on my dyno...

The thing about Chris is he is not againsit development like many guys that jig up a system and just bend hundreds of them, and never open to change..

I have seen this in the development of his TIV conversion exhaust as I spent a solid day on Thursday testing his new EVO header and two new muffler arrangements. He is always open to input and to my results, he never argues he just starts talking about what we think will make it better...

I have his 914 system on my car with the 2316 Hybrid engine.... Enough power to spin through the first three gears and it sounds like none other. Chri's headers create the absolute most torque with the flattest curve I have ever seen.... Too many people buy things from peak numbers- and thats just not wise! Look down in the power curve for the true testamant to what the power is like- especially for a street car.

I fully endorse Chris' header and thats basically only because Chri's is not only an extreme fabricator but also because he is a developer that is dedicated to what he brings to the table.

I agree with Jake that too many people buy their parts (headers in this case) with top end numbers in mind...instead of usable horsepower.

Taking into account what Jake just said...I can't wait to try Chris' pipe on the next motor...time to get started on it.

QUOTE (HotRod @ May 2 2005, 11:06 AM)

it wouldn't fit...the motor is 18mm narrower than stock and it just wouldn't line up

Greg,
Trim a little length off of the #3 & 4 pipes to get it to fit.
The best way to figure out how much is to attach the main section, then slide in the 3 and 4 pipes. If they bottom out just measure how much further you need to go until the flange will seat and cut that much off the end of the tube.
The heads on my full prep engine were cut pretty deep and I had no trouble attaching my header to the engine.
18mm does sound like a lot though, lol.

As stated above KH with Supertrapp muffler is a budget AX power enhancer. My stock 1.8 came alive with the KH headers and the Supertrapp. I can feel a significant power difference across the entire rpm range even with that "power robbing" muffler. I'm amazed that I even get low end torque increases with this setup. In uphill corners where my car would bog down it pulls now.

I run 15 disks on my AX Supertrapp and it makes great power and you can get away with running it on the street its not like running an open megaphone as some will have you believe. I havent been banned at any 92 db events running 15 disks. Power is still great with 12 disks and it is acceptable for the street. It all comes down to your or your neighbors noise tolerence. I live on a few acres in the mountains and I dont have to worry about neighbors. If my car made much more power with disks off I'd do it, but it doesnt, so I'm not sure why so many people say that the system is a power robber. I think people who report poor power are below 7-8 disks or have disks that arent installed properly.

If other mufflers make make more power than I'm more than willing to expereiment. You'll also note that few offer imperical data to back their claims of power robbing properties of a properly setup Supertrapp with a healthy amount of disks installed. It would be pretty easy to Dyno a Supertrapp with 5 or 6 disks and show below average power, but once youre over 7-8 disks power is great.

Pluses are its tons lighter than most anything else. Cons are terrible finnish that burns off and lets tubes rus. Something that isnt mention often is that if you have a later model car with those bumper tits the Supertrapp will melt the driver side tit with great effeciency.

Rather than dealing with changing disks all the time I bought a second Supertrapp for $125 from Summit racing. I set one up for AX and the other for street. Changing disks is a hassel for me and those little allen head bolts tend to snap off.

15 disks?! That's like 1.5 inches worth?

I'm running 9 right now, and the thing is uncomfortably loud for extended periods. Perhaps its because a number of things have fallen out of my car including the backpad, the rubber isolation mat behind the backpad, the haybale sound deadening mat inside the engine bay, and the engine lid / raintray.

As a matter of fact, my ears are still ringing from yesterdays activities -- three 20 minute sessions of zinging from 3K to 5K RPM. I couldn't wear earplugs on account they would have defeated the purpose of having an instructor in the car.

I suspect the benefit of the exhaust system is the Kerry Hunter half, not the SuperTrapp half.

Grant, I'm not sure I understand. Are you saying power is better with 15 or with 12? Apparently the engine needs a certain amount of back pressure or it loses power. Too few discs results in less power, not more, right?

QUOTE (Jake Raby @ May 2 2005, 07:36 AM)

Nothing for the 914 has touched Chris' system on my dyno... The thing about Chris is he is not againsit development like many guys that jig up a system and just bend hundreds of them, and never open to change.. I have seen this in the development of his TIV conversion exhaust as I spent a solid day on Thursday testing his new EVO header and two new muffler arrangements. He is always open to input and to my results, he never argues he just starts talking about what we think will make it better... I have his 914 system on my car with the 2316 Hybrid engine.... Enough power to spin through the first three gears and it sounds like none other. Chri's headers create the absolute most torque with the flattest curve I have ever seen.... Too many people buy things from peak numbers- and thats just not wise! Look down in the power curve for the true testamant to what the power is like- especially for a street car. I fully endorse Chris' header and thats basically only because Chri's is not only an extreme fabricator but also because he is a developer that is dedicated to what he brings to the table.

I would disagree with you in that the KH header makes a signficant differnce across the entire RPM range not just peak. But my sense is Kerry has enough sense not to come on a 914 board and promote his products. Just ask a few people who have seen my car run in Nor Cal Ax's. My car is pretty darn fast for a basically stock 1.8 engine with a header (of couse this is all relative - a stock 1.8 with a header is like a slow out of tune stock 2.0). I saw signficant imporvements in my AX times when I put the header on the car and thats certainly not all top end power. I have much more low end usable power with this system as well.

I have more than 25 years driving and 200,000 plus miles in 1.7, 2.0 and 1.8 914's my butt feel of power increase with this Kerry Hunter header says its pretty impressive across the power band. Its not just top end.

I think Kerry did a damn fine job with a header that costs a 1/4 of the Tangerine system. Anyone on a buget will be well served by his product.

QUOTE (Porsche Rescue @ May 2 2005, 04:26 PM)

Grant, I'm not sure I understand. Are you saying power is better with 15 or with 12? Apparently the engine needs a certain amount of back pressure or it loses power. Too few discs results in less power, not more, right?

The more the better from my expereince so far. 15 seems to be the best number for my car and I dont see any drop in low end performance, in fact it seems to get better low end with 15. Below 12 disks I feel a differnce in the mid to high end power (less power), but noise is more acceptable for street driving. I talked to somone else and he uses 14 disks on a 2056cc engine and his car is very fast as well.

QUOTE (Cloudbuster @ May 2 2005, 04:05 PM)

15 disks?!  That's like 1.5 inches worth? I'm running 9 right now, and the thing is uncomfortably loud for extended periods.  Perhaps its because a number of things have fallen out of my car including the backpad, the rubber isolation mat behind the backpad, the haybale sound deadening mat inside the engine bay, and the engine lid / raintray. As a matter of fact, my ears are still ringing from yesterdays activities -- three 20 minute sessions of zinging from 3K to 5K RPM.  I couldn't wear earplugs on account they would have defeated the purpose of having an instructor in the car. I suspect the benefit of the exhaust system is the Kerry Hunter half, not the SuperTrapp half.

Us folks in the Nor Cal mountians who used to drive baja bugs with big stingers in High School during the 70's cant hear very well now But seriously my car doesnt have any firewall mat and I dont need ear plugs. Yeah its agressive but loud in the cockpit? My 15 disk AX setup isnt that bad. And my 12 disk street setup is hardly ear plug material. 9 is almost down right civil.

Now I'm really confused.........12 discs is quieter than 15? I thought more discs, more quiet.
Reason I am so inquisistive is that I have a used system on the way which I plan to install on my AX car. It is a 2.0 with euro. p&c's, lightened flywheel, stock fuel injection. Should I start with 15 and go from there?

QUOTE (Porsche Rescue @ May 2 2005, 05:26 PM)

Now I'm really confused.........12 discs is quieter than 15? I thought more discs, more quiet. Reason I am so inquisistive is that I have a used system on the way which I plan to install on my AX car. It is a 2.0 with euro. p&c's, lightened flywheel, stock fuel injection. Should I start with 15 and go from there?

Yeah the less disks you use the more restrictive the system gets. Each disk creates space for exhaust gas to escape. Fewer disks means less room for exhaust gas to escape but less noise. I had similar thoughts to you until I saw the muffler. And 15 is good for AX just a little noisey for the street. After some time in the car you will feel like you have been driving a race car, but your helmet truly is enough to buffer the sound. Thats why I have two mufflers. You wont get 15 spacers with the stock KH system. I think its 12 that comes with the muffler. You can buy additional spacers from Summit Racing or other places that carry the Supercrapp. One other thought Supercrapp is like a cigarette you smoke it and then throw it away - its not the best quality muffler I have seen.

Thanks Grant. I'm looking forward to giving it a try. When this thread started I thought I had made a mistake. The Tangerine headers may be great but when I looked at the price they were not an option for me. I thought the KH system was expensive enough.

I ran a KH with suppertrapp for about a year on my 2056...ran at 12 disks on the street it was decent, a little annoying on the street (gutted interior also). I purchased it used for about 250 complete.

Two years ago I switched to a used eurorace header and turbo muffler, purchased it used for 300. The sound is much better in my opinion, more throat, less sputter...and my butt dyno noticed more low and midrange power, top end was probably a draw. I also noticed less exhaust leaks and I really dig the stub pipe design. I would jump on Chris's system in a heart beat if I ever find one used or fall into some cash...But for the budget I think the eurorace header is hard to beat. You get the stub pipes, I have seen a couple reviews that show it making a little more power than the KH, and in my opinion the sound is much better.

They are a deal at 500 new, and I just couldn't pass 300 used

Good luck,

Tony

Chuck the supercraps and get either a Moroso Spiral Flow or one of the Magna Flow mufflers. They will be much better. I also like the FLowmaster. Ran a 3 chamber on my street car for awhile. INtake noise outdid exhaust all the time. Might be worth trying a chamber as well. One reason Supercraps and that type of muffler don't work is there is not enough area inside it to allow proper expansion and slowing of the exhaust gases. The problem with the big mufflers is packaging. Take a look at the mufflers for the late model boxters and 996s. They have a lots of volumn.

A two stage muffler would be the best. A vaccum or soleniod controlled setup that would bypass a larger chamber with a straight through pipe upon WOT would really be cool. If I only had time for another project.

Check out the February 2002 issue of Grassroots Motorsports magazine www.grmotorsports.com to see the complete dyno results of the 914-4 header system on a relative stock 2.0 litre engine being built for their 914 Project car.

"The system was a standout on the Williams Racing engine dyno,
producing a maximum of 111.3 horsepower at 5100 rpms - 1 4.9
horsepower increase over the stock system.... The Kerry Hunter system was louder, but certainly not objectionable." "The Kerry Hunter system is also very light. At 21 pounds, it is 16 pounds lighter that the complete Bursch system fitted with the stainless steel heat exchangers" Tim Suddard, editor

They also tested Chris's which made more HP I can't find the actual results. KH has never stated that his make more HP than others header . Its all a trade off of how big your wallet is vs how much is it worth to you.

A little background when Kerry made his first headers he did because he could not find anything that he liked. I begged him to make me up a set, which he did. I got the second set made.

Note: When you put the screws in the super trap use anit seize and make sure its cold.

Cha914, Is the eurorace system the one that runs along the passenger side of the engine and melts the plastic on the clutch cable? I had one system like that on a race car, it actually melted the clutch pully too.

I have always been happy with the KH system, although Chris' system I think is of a better quality, it's over twice as much. I do like he design of the Tangerine system in that it goes over the half shaft and provides room for different muffler options.

Chris, I did do a some trimming but decided that I didn';t want to trim too much and make the header useless for other motors. I'll just keep the KH on the flat top motor and use the Tangerine system on the dome motors.

Yeah, the eurorace is the one that will melt your clutch cable if you aren't careful. I fabed up a little alumn heat shield and used some high temp cloth and no worries yet...Plus I had the exhaust ceramic coated, so that has helped also...

Good luck with that tangerine setup...

Tony

Ok so what it sounds like is that KH headers are good but its the STrapps that need improvement. Will the other alternatives mentioned fit every thing or will modifying be manditory.
E

I would think that the KH system would be good. The Tangerine system is the best (as tested by Jake). But let us not forget the reason these systems are good. STOCK SUCKS!!!!!!! Having said that get the best you can afford and dial in your fuel to suit. Dont like the supertraps, get something else. You are probably still going to be better than stock. If not you did something wrong.
Personally I run stock cause i'm broke.

Chris, whant to donate an old used system? Please!?!?!?!?

QUOTE (914fan @ May 4 2005, 12:01 AM)

STOCK SUCKS!!!!!!! Chris, whant to donate an old used system? Please!?!?!?!?

The stock muffler on SSI's made more power than a Bursch in the GRM tests.

I will have a used system up for auction later this year once I make an Evo system for my race car.
I may auction off the one on my white car too. It has the HE option added.
The Evo won't yield any more power on a stock engine or other engines with less than 6500 redline, but will kick ass on high rpm engines.
I don't think you can beat the bang for buck of the KHH on small, mild engines, but the sound is a problem along with other shortcomings that are typical with budget products.

Ahh,
But if you Upgrade to the SSI you are no longer stock. Even a Monza (read 4 tip POS) is better than stock everything. The bursch on factory exchangers is an improvement. I would imagine that the SSI's would be next and then KH. But if you actualy build a motor (not stock) Tangerine is the only way to go. Ofcouse Jake would need to build the motor to fully utilise the Tangerine.

Ok thats 2 endorsements for Tangerine (I must be getting close to that free system by now) and 1 for Jake. Cool I can now work on that free engine / header combo.

When should I expect delivery