TC Racing port recommendation,,helpful info

I spoke with Tom Carlson of TC racing today about porting and here's pretty much what he said. I told him what I had done to my bike and what I plan on doing,,,putting XR cam and 416 piston in it and he said I would NOT notice a difference in power if I were to get the head ported. Now if I put his custom TC racing pipe on,,(which is a full race pipe) larger carb, a TC racing cam, and remove my airbox lid then porting would make a difference.

So after about a 15 minute talk with Tom,,,Porting while running a stock carb, XR cam, 416 piston, will not make a noticable difference, but of course he want's to sell me all his products also.

He almost says that porting on a 400ex is not necessary,,UNLESS you add a wilder/race cam,,,bore it to a 416/426,,and get a bigger carb of any kind. Which he is also talking about taking our 28 HP 400ex's and making them into 50 HP monsters...

This is not my opinion or advice I'm just relaying this on to the rest of you,,,Tom Carlson is a very respected engine builder and does know what he's talking about....it's up to you to take his advice...I still think I'll be getting a play port done, which is just cleaning the ports up a little,,,no major work...

[465Stroker]

Sounds like TC Racing does not want to waste your money on modifications that will not work effectively with your current list of equipment. Sure you can clean up (play porting) your stock ports for an additional .50 horsepower, but to me that sounds like a waste of money compaired to the same amount performance you could gain with having your quad jetted right, geared right, additional weight removed, etc, etc.
Also, TC Racing's porting has extensive testing to match their exhausts, carb sizes, etc...to give the most out of your motor.

Well I have had mine done and i could tell a major differ he can say what he wants but I have had it done and i know it worked. Common knowledge, (intake) the more you can in and the more you can get out (Exhuast) the better your motor will run

[Leo]

from what I've been told the 400EX head flows well enough in stock form for mildy modified engines...

from a price/hp perspective it's not a very cost effective mod untill you start getting into major work (at which point money isn't an issue)...

there is a hell of a lot more to it than most people think... I'd REALLY have to have faith in someone before I let them take a grinder to my cylinder head.. it's a lot easier to make things worse, than it is to make them better.

[I'm talking about major port modification here, not a simple cleanup of the casting]

so I guess it depends, if you just want the ports cleaned up (there is always a casting imperfection or 2) then it's fine.. but if your talking about a $400 full race port/polish unless your putting some serious parts in, don't bother save the money for an FCR

my .02

Leo

[51]

i just got my engine back from tc and he help me out bunches....i reccomend everybody to him...he seems to be a great guy and did an awsome job on my bike....it rips and about the port thing i agree with him...yea sure you might be able to get more fuel into it with the ports...but if you don't got the carb to back it up or the cam to open em up then there isn't really a reason to do it...mine was ported when i got it so i can't really do a side by side comparison but i'd wait if i were you rico until you get a carb and all that good stuff...hope this helps

[86atc250r]

Leo and Tom are correct.

The 400 head flows well from the factory. Porting yeilds only small returns even on engines that need it.

There's a reason stock cylinder heads aren't cast with huge ports... It's because of velocity. Larger ports equal less velocity which kills low end power. Hogging out ports to "get more air into the cylinder" isn't the way to think. It's MUCH more complex than that.

The 400EX head has a fairly good design that flows well without compromising too much on velocity for a wide range of configurations. Most people "in the know" won't try selling you porting until you have substantial other mods to back them up. Even then, they'll usually let you know that the porting is only to try to extract that last tiny bit of power out.

Personally, I've had a little work done to my head - mostly minor casting cleanup (the 400's casting is pretty clean), port matching to the intake and exhaust, a little bowl work and combustion chamber polishing.

I don't think 50 horsepower even with race gas and a 440 kit is a resonable quote. Try low 40s. Also don't just ask one engine- builder, you should call up atleast 5 and take notes on what each one has to say, and try to cut through all the crap they tell you. I personally will use LRD when I build my engine, just don't believe everything they will tell you on the phone, find out using many sources, and ultimately your own mind. For instance, somebody was saying head porting will not do anything for you, and a couple people actually backed him up, yet NOBODY showed any mathematics involved with blue-printing engines, no dyno charts, or any testing done on the flow bench, or any other feesable FACTS to back yourself up, just theory. If you really want to get involved with your engine do your own research, or tell an engine builder what you expect out of your engine, and pay him to do the work for you. THINK FORYOURSELF, QUESTION AUTHORITIES!

[86atc250r]

Hmm...

Well, instead of sending my engine off and praying, I built it myself. So I guess my opinions don't count.

How many dyno runs have you looked at? I've looked at more than a few myself. I've also talked with several engine builders & people that have work done. I've also seen what works and what doesn't. Unfortunately I don't have a dyno myself, but I've been told by those that do that even on a heavily built engine, "race" porting is good for about 1hp. What I've seen at the sand drags and races back that up.

I figured that given my posting history here and elsewhere, any idiot with half a brain would know that I wasn't just posting an agreement, without any info or experience to back it up. I didn't think a simple post in a web based forum required an answer that involved heavy math or hours on the flow bench to back it up.

BTW, I think TC likes to quote crank HP - in that case, 50's is about right. Your estimation of low 40's to the back wheels is also correct. A VERY heavily built 400 can go into the 50's at the rear wheel, however... I don't think it's probably worth spending the money and the potential reliability problems though.

Oh yeah - here's your dyno run for the 51 rwhp 473EX
(I didn't link it because it has to be pasted into a browser address window, otherwise Geocities will block you from viewing it)

http://www.geocities.com/Baja/Ravine/4093/fdo.gif

If you still have any disagreements, there are ways to go about posting them without pissing anyone off, of coming off as an A-hole.

Then again no one person is the same nor are all engines and riders the same. You can take 2 of the same quad and there will be differences in a dyno run

[86atc250r]

Yes, there will be differences, albeit small and mostly insignificant - unless there is a large discrepency somewhere.

Engines of the same family respond to the same mods. Porting is not something that will work for one EX and not for the other - given they're built the same.

I just picked up my 400 from Trinity Racing in SOCAL. I bought the White Bros slip on pipe after the Pipe Shootout in Dirt wheels.
The airbox has large drilled holes, that the only mods so far.

They showed it made 32HP on the DYNO.

The Trinity DYNO showed a peak of 28.4@51.1MPH.
The first one with the suggested jet showed a peak of 25.2@45MPH.

I find it hard to believe that a stock bike makes a claim of 28RWHP and a slip-on pipe with jetting brings it to 32HP. To get the HP up to 35ish they recommended the 440, w/midrange cam, and of course their new pipe, with their port&polishe, chamber work. They also said their new pipe alone would add 5hp. They also said that after 30 days if I didn't like their pipe I could bring it back for a full refund.

Allways go for the Money where their mouth is and write it down.

[JabberJaw]

Tool, Just some questions for you to think about:


I don't think 50 horsepower even with race gas and a 440 kit is a resonable quote. Try low 40s.

In your own words:

YOU showed no mathematics involved with blue-printing engines, no dyno charts, or any testing done on the flow bench, or any other feesable FACTS to back yourself up!



Also don't just ask one engine- builder, you should call up atleast 5 and take notes on what each one has to say, and try to cut through all the crap they tell you.

I think next time I get a liver transplant I will try this angle...maybe I will just do the work myself.


Tell an engine builder what you expect out of your engine, and pay him to do the work for you.

What if he's a crappy engine builder? I think the ONLY research you need to do...is find a reliable honest mechanic. Some of us would rather spend our time riding, rather than learning about engines.



THINK FOR YOURSELF, QUESTION AUTHORITIES!

Most people know this will get you NO where! But you will figure that out eventually. And if you hadn't noticed, most of us have no authority here. Why don't you call your local police station and harrass them for a while?

Simply put...your attitude sucks!

jabberjaw....How old are you? Just wondering cause you sound young.

[Moddedx]

Originally posted by TOOL
I don't think 50 horsepower even with race gas and a 440 kit is a resonable quote. Try low 40s. Also don't just ask one engine- builder, you should call up atleast 5 and take notes on what each one has to say, and try to cut through all the crap they tell you. I personally will use LRD when I build my engine, just don't believe everything they will tell you on the phone, find out using many sources, and ultimately your own mind. For instance, somebody was saying head porting will not do anything for you, and a couple people actually backed him up, yet NOBODY showed any mathematics involved with blue-printing engines, no dyno charts, or any testing done on the flow bench, or any other feesable FACTS to back yourself up, just theory. If you really want to get involved with your engine do your own research, or tell an engine builder what you expect out of your engine, and pay him to do the work for you. THINK FORYOURSELF, QUESTION AUTHORITIES!

I dont think it would be that hard to pull 50 HP from a 400ex, your comments acts as if though it would be really hard.. TC was getting 50 HP from a 250X engine back when Travis Spader was running 250X's.....

[Tommy 17]

i think it possible to get 50+ hp out of our 400ex. i have a xr400 cam, pc t-4 pipe and header, no air box lid. i ordered my piston yesterday its a je 10.8:1 and i am having a guy build my quad for me, hes not a big name guy to many of u buts i rode 2 400exs hes built and they run hard. i also rode a 416ex just 2 days ago and let me tell u these stock bore 400s will keep up. hes does sometin to ur carb i dunno what ,and hes goin to do some porting, jetting, shave my fly wheel and a few more things for me too all at a cheap price 500$ that includes parts. this guy knows what hes doin he been building quads and dirtbike since 1986 the year the 250r came out. he went to some high tech school just for quads and bikes. his name is rob gremly. he has 3 other 400exs and 1 xr 50 ahead of me so i am lookin till december or january till its finished i will get u his phone number if anyone in pa wants it.


JABBER THATS THE FIRST POST I HAVE SEEN U MAKE THAT ACTUALLY DOESN'T JOKE AROUND MUCH BUT THE LIVER ONE HAHA.