Some Progress In Finding More Engine Performance

[dynajohn]

My 2016 Thruxton R has undergone further testing to see if we could get more HP out of the 1200 CC motor. This was never an attempt to get additional performance through radical changes like increasing displacement, cylinder head porting, or installing a race cam which would require replacement valve springs. The modifications currently are a power commander 5, Vance & Hines (Triumph) slip on's with DB plugs removed, a cat delete, removal of the upper portion of the air intake snorkel, installation of a mild cam designed by Chad Wells & dyno tuning by Chad Wells at Commonwealth Cycle in Louisville KY. We completed the cam install, testing & tuning on 8/18/17.

Before I get into the results I want to discuss how Triumph designed some limitations into the 1200 Triumphs in order to achieve a broad torque band and still achieve the HP target they wanted on the Thruxton. First the cam was designed with negative overlap which helps produce great low & mid range torque and with sufficient duration and valve lift to reach they're HP target. The exhaust pipes which are double wall have a outer diameter of 1.759 inches (44.7 mm) and a inner diameter of 1.494" (37.95 mm). The inner inlet & outlet diameter of the stock cat & the cat eliminator is further reduced to 1.363" (34.64 mm). The inside diameter of this exhaust system is designed to produce high velocity and boost torque. Triumph did use two crossover pipes (one in front of the engine and the second ahead of the cat) to reduce back pressure. The bikes ECU which controls fueling, ignition & throttle position as well as the ABS & traction control has at least one major restriction we have found. In road mode the throttle plates are closed from 100% open to 80% open at 6,750 RPM. In sport mode the same thing happens but at 7,000 RPM instead of 6,750 rpm. The stock ECU setting for the rev limiter is 7,300 RPM.

Chad Wells used Web Cam (large US aftermarket cam grinder) and specified a replacement cam with more duration, different CL's, and the same lift as the stock cams. This cam design is a first attempt at a drop in street cam that uses the stock valve springs. Chad also used the power commander 5 rev extender feature to increase the rpm limit from the stock 7,300 to 7,700 RPM. We could not do anything about the ECU reducing the throttle openings from 100% to 80% at 7,000 rpm. You can see the effect of closing down the throttle opening from 100% to 80% on the blue line (run file 003). The blue lines are the dyno HP & TQ with the bike completely stock after it was broken in on Commonwealth's dyno 2/08/17. The red lines (run file o49) are the results now. Current HP is 94.04 and TQ is 78.11. The cam has increased HP & TQ from 3,700 to 7,700 rpm. I think there is 100 plus HP potential if the ECU can be re-programmed to eliminate the throttle plate restriction above 7,000 rpm as well as reducing the exhaust restriction caused by the small inner pipe diameter. I am sug

gesting larger ID primary pipes that connect directly to the mufflers. I am attaching a dyno sheet and four pictures of the cam install and my bike in Chad's dyno room.

 

[dynajohn]

Sorry about the posting of the pictures and dyno sheet twice in my post. This was my first time uploading images to this site. As suggested in my post we believe there is a HP restriction from the small I.D. of the primary exhaust pipes and even smaller I.D. of the inlet & outlet of the cat eliminator. I ordered an Arrow set of competition headers today which delete the cat eliminator and connect directly to the mufflers. This is a Arrow part number 71664MI. These are single wall stainless steel pipes (lighter and larger I.D. measurement). We will see if this frees up some more HP & TQ. The ECU restriction which closes the throttle plates from 100% to 80% above 7,000 RPM will have to wait until some genius decides to offer a re-flash of the stock ECU. If enough of you contact Guhl Performance asking for a Triumph 1200 Thruxton re-flash Don Guhl may take the project on. According to the part numbers this is the same ECU used on the 1200cc T-120 Bonneville and possibly all the 1200cc motors.

 

[DaveArt]

Although I'm pretty happy with my R's performance, there's always need for improvement. To that end, I've installed Cone Engineering shorties and removed the upper portion of the air intake snorkel. The bike seems to like it. My concern is that if I go too far, I'll have a snarling beast on my hands. You know, the kind of bike that is all but unmanageable on the street. Or a hand grenade that's unreliable. Breakdowns suck big time. Do you have an address for Guhl Performance? I'd certainly be interested in a reflash.

 

[dynajohn]

Although I'm pretty happy with my R's performance, there's always need for improvement. To that end, I've installed Cone Engineering shorties and removed the upper portion of the air intake snorkel. The bike seems to like it. My concern is that if I go too far, I'll have a snarling beast on my hands. You know, the kind of bike that is all but unmanageable on the street. Or a hand grenade that's unreliable. Breakdowns suck big time. Do you have an address for Guhl Performance? I'd certainly be interested in a reflash.

Dave I have some of the same concerns you do. That is why I am not interested in getting into serious internal engine modifications. To that end I have so far installed a power commander 5 to be able to control the fuel and ignition advance for safety and performance. Removed the upper portion of the intake snorkel, installed a cat delete crossover, and installed the V&H slipon's with the sound baffles removed. The only way Guhl Motors is going to do the R&D to develop a re-flash is if he receives enough demand to make it profitable. With a re-flash he could remove all the restrictions Triumph programmed into the ECU or just the ones you want removed. He could install new fuel & ignition maps, remove the throttle restriction above 6,750 RPM, raise the RPM limiter. I have used his company for ECU re-flashes on my Kawasaki ZX-14 & my Honda VFR 1200 with great results.

The Triumph 1200 is very conservately tuned and with the changes I have made including raising the rev limiter to 7,700 RPM with the mild cams installed does not make the bike unmanageable on the street. Whhen the arrow pipes are installed we will re-test & tune for any changes and hopefully gain some more HP & TQ. But the big obstacle remains the stock ECU's resetting the throttle plates position back from 100% open to 80% open above 6,750 RPM's and the stock conservative RPM limiter.

 

[dynajohn]

Dave sorry for omitting this contact information for Guhl Motors

Phone 717-618-4212
Address 102 S State Street, Ephrata PA, 17522-2411
e-mail [email protected]

We need enough forum members to call or e-mail Don Guhl and express a need for him to develop a re-flash for the Triumph 1200 bikes (Thruxton, Thruxton R, T-120 Bonneville) for him to be interested. He developed a re-flash for gold wings when enough riders asked him for one.

 

[DaveArt]

Does the cat delete make it significantly louder? I was considering it, but my Cone Engineering shorties are fairly loud as is. I don't want to piss off the neighbors.

 

[dynajohn]

Yes, it is louder but not significantly. If the Cone mufflers came with sound restrictors you should try the mufflers with & without them if you install the cat delete. It is really difficult to feel a small difference in HP & TQ (2-3 HP) by the seat of your pants. That's why dyno testing on the same dyno is useful but expensive for the average guy.

 

[DaveArt]

Nope, the Cone exhaust doesn't come with any kind of restrictors. They're pretty much wide open. But I like the way they look and sound. And it was hell just purchasing them ( I live in California), so I don't plan on changing them out.

 

[DaveM]

@dynajohn it looks like you really going all out here to find the best combination that you possibly can, what are your projected results or what results would you be happy with when done. I know any biker no matter what you have you always looking for that bit extra that can be found. I suppose it is also just the fun of doing it and then knowing that you did get it right in the end as well.

 

[dynajohn]

Dave these little projects are a hobby of mine. The last one was a 2013 Honda VFR 1200. The Honda had more obvious problems than the Thruxton. Actually the Thruxton doesn't have any problems if you just want to ride it and leave it stock. The Honda had performance limiters that restricted it's performance in 1st & 2nd gear as well as a big hole in the power band around 3,500 to 4,500 RPM. It also had a top speed limiter. I knew all this before I bought the bike but I knew it had a lot of potential and I had connections in the aftermarket that I knew could help me. Don Guhl was interested in developing a ECU re-flash for the VFR and that was the key to unlocking most of that potential and he was willing to help me. The Thruxton has some of the same software power restrictions but I have not found any firm that has enough interest so far. With the throttle plates limited to 80% above 6,750 or 7,000 RPM depending on which mode you are in I doubt I will see anything over 97 or 98 HP. These projects are like peeling an onion. You can usually find the easy stuff fairly easily. Almost all mfg's. use a richer fuel mixture than is ideal especially at higher RPM to protect the engine. The Thruxton has a short enough stroke that it could be run up to 8,500 to 8,800 RPM safely. The piston speed at the stock 7,200 RPM rev limiter is very conservative. I know the rod bearings and oiling system are safe to over 10,500 RPM because a race shop in Texas that is developing a de-stroked 1200 to 900 cc has gotten 118 HP at those RPM's. I think we could fairly easily get over 100 RWHP out of this motor without any internal modification other than a drop in cam if we can get the ECU software changed to remove the throttle plate restriction. I would be satisfied with at or near that 100 HP figure. I don't think there is much interest here in even going that far. This is a very good balanced package right off the assembly line that will satisfy most buyers. Not very many buyers will go any further than installing a set of aftermarket mufflers and removing the top section of the air inlet snorkel.

 

[DaveM]

I would be satisfied with at or near that 100 HP figure. I don't think there is much interest here in even going that far. This is a very good balanced package right off the assembly line that will satisfy most buyers. Not very many buyers will go any further than installing a set of aftermarket mufflers and removing the top section of the air inlet snorkel.

I think the 100 HP mark is ok and is in the price range that most hobby tweakers would be in as well. I know that I have always tried all the smaller and affordable tweaks on my bike to just get that few more HP and even if it is not that remarkable just doing it is loads of fun itself.

 

[dynajohn]

Dave we shall see when I get the Arrow head pipes installed and dyno tuned again for the change. That 100 HP or more is easily realistic. the two keys to that power level are a ECU re-flash to remove the throttle plate restriction and spinning the engine to a higher RPM. Right now you have to use a power commander 5 to reprogram the stock fuel and ignition. With a GUHL re-flash you could get everything the power commander does for you plus eliminating the stock ECU restriction. The re-flash costs $395 from Guhl. That's about the same price as the PC 5 not counting install. What we need is for forum members to call Guhl and request a ECU re-flash. Hell he did it for the Gold Wing guys when enough of them requested he develop one for them.

 

[DaveM]

Well if you can get the ECU re-flash done then that would really be a plus. When do you expect the pipes to arrive as I have heard some great things about them.

 

[dynajohn]

Dave they shipped today. I would expect they will arrive Friday or Saturday. I will have to take them & the bike to Commonwealth and have Chad Wells install them. Can't handle the install myself right now. I will post the results with dyno sheets and pictures when complete.

 

[DaveM]

Dave they shipped today. I would expect they will arrive Friday or Saturday. I will have to take them & the bike to Commonwealth and have Chad Wells install them. Can't handle the install myself right now. I will post the results with dyno sheets and pictures when complete.

That is not bad at all and I will be looking forward to those photos

 

[dynajohn]

Sorry to say it will probably be late Nov. before Chad is able to install the new pipes and dyno-tune for the changes. His calendar is that full with motor builds, dyno appointments and all the other regular duties he has as service manager at Commonwealth. I hope the Arrow pipes compliment the changes we already made and we get positive results.

I used to do all my own mechanical work except the dyno tuning but unfortunately except for normal routine maintenance that is no longer possible so I have to depend on others and wait on their schedules. Since he can't get to my bike I am moving on for now to just riding my bikes and enjoying the fall weather here in Kentucky.

 

[DaveM]

Well at least you still able to ride while waiting for the other work to be done.

 

[dynajohn]

The Thruxton goes in tomorrow for the new pipes to be installed. They will not get to it before next week but I am leaving Friday on a 5 day ride. In addition I am having them install a aftermarket air filter before putting the bike back on the dyno for any required re-tuning. After we get the best tune we are going to slip the stock mufflers back on in place of the V&H mufflers to see how much difference there is. Before we installed the cam the stock mufflers actually made more HP than the V&H mufflers with appropriate tuning for each. I should have some more information before the end of the month.

 

[RHB]

It is my understanding that simply drilling the ECU and extracting the code, (as time consuming as that is), can't be done on the water cooled twins due to a locked ECU state. I consulted a couple of top tuners and dyno operators and they confirmed this, at least for the present time. Can Guhl even do this? If it were that easy I would suspect it would have been done already.
It would be great if someone could. But in any event, I have a street twin, and most, or actually all, of the dyno tuning and modding has been done on the 1200cc engines. Minus the ST tracker done a year or so ago with Triumphs co-operation and supplied maps and goodies. nobody is talking.

 

[dynajohn]

Do not let any shop that drills into you're ECU work on it. If anybody can do it Guhl Performance can. Guhl does all re-programming thru the stock connectors, he does not cut into the ECU. He told me he was concentrating all his time on the Japanese bikes. Currently he does no European bikes as far as I know. This guy really knows his business and until he is persuaded to take on the Triumph My ECU will remain stock. Don Guhl has done ECU work for Honda's factory Indy team. I have repeatedly posted on this forum that if you are interested in a ECU with the stock restrictions removed CALL his shop and request he re-flash you're ECU. He will have to see enough demand before he is going to put the R&D into mapping the Triumph ECU code to perform re-flashes.