# Has anyone done internals...?



## MasterJetti08 (Mar 1, 2012)

Not that I'm planning on doing this any time soon, but just out of curiosity, has anyone done the internals (rods and pistons) on their 2.5? Also , what is the stock compression on our engines and what would be the gains in putting an 11:1 compression piston in there? And while we're on these subjects, has anyone ever ported the head? Bore? I was always planning on eventually putting a turbo on my car but now that IE is making a cam, I think it would be really cool to just do a completely built NA engine.


----------



## lessthanalex (Oct 12, 2009)

I think people have discussed port n polish before. From my recollection, we have an extremely high flowing head so the gains wouldn't be as big as on other motors. I think INA engineering has done port polish and offers it but I could be wrong. As far as pistons, pretty sure most who have done them have gone low compression for turbo applications. The only "problem" I can see with going high compression is getting an appropriate tune for the hardware, but that can be solved I'm sure between talking to either C2 or UM.


----------



## thygreyt (Jun 7, 2009)

raising compression to 11:1 or 12 for that matter is possible.

there arent much gains from doing so.. maybe 10, 20 hp AT THE VERY most.
In fact, theoretically, the gains should only be ~15 hp.

to get proper NA power, you need to go higher... ~13 or 14.
but then fuel would detonate... even with e85 you would be pushing it...
at the same time, be prepared to change head gaskets left and right.

port and polish is usually more trouble than whats worth, from the tuning point of view.

in reality, all this, will net you 20-30 hp if pushing it a lot... and it would be seriously expensive.
Turbo is just as much for .... all the power you can want.


----------



## MasterJetti08 (Mar 1, 2012)

I see. That's disappointing. It would be awesome to get some significant power with an NA.


----------



## bobsuncle (Oct 18, 2012)

MasterJetti08 said:


> I see. That's disappointing. It would be awesome to get some significant power with an NA.


Be patient grasshopper, cams, a belt tensioner and a better SRI are coming from IE.

Raising compression alongside cams, valvetrain and a good head job (maybe even a slight shave) w/ E85 we'll be looking at pretty damn solid numbers. No way anyone is going to bust 300WHP, but 250WHP+ is going to be commonplace.


----------



## bobsuncle (Oct 18, 2012)

lessthanalex said:


> The only "problem" I can see with going high compression is getting an appropriate tune for the hardware


If you live somewhere like DFW custom tuning an ECU that has to get shipped off site is a major obstacle. Frankly it's the MAIN obstacle.


----------



## MasterJetti08 (Mar 1, 2012)

Thanks for keeping my dreams alive. Lol. :thumbup::thumbup:


----------



## HelloMyNameIs (Aug 2, 2011)

bobsuncle said:


> If you live somewhere like DFW custom tuning an ECU that has to get shipped off site is a major obstacle. Frankly it's the MAIN obstacle.


C2 has a self flasher now: http://www.c2motorsports.com/index....n=com_virtuemart&Itemid=58&vmcchk=1&Itemid=58

Yes you do pay a premium for the convenience. But it finally got me to 'chip' my car in my own garage. Would be cool if other tuners start heading in this direction as well for remote tuning.


----------



## bobsuncle (Oct 18, 2012)

MasterJetti08 said:


> Thanks for keeping my dreams alive. Lol. :thumbup::thumbup:


I think we'll be seeing roughly a 265WHP maximum unless there are commercial ITBs --but that's a LOT of sketchy napkin math, and not something I did any modeling on. 250WHP will happen for sure with UM E85 tune, cams, valvetrain, port&polish, internals, SRI, ram/CAI, headers, and 2.25" exhaust. Make sure to leave the stock cat b/c otherwise you'll lose too much backpressure.

This motor has yet to really give us it's true glory. There's about to be an EXPLOSION of aftermarket parts for the VW 2.5L.


----------



## bobsuncle (Oct 18, 2012)

HelloMyNameIs said:


> C2 has a self flasher now: http://www.c2motorsports.com/index....n=com_virtuemart&Itemid=58&vmcchk=1&Itemid=58
> 
> Yes you do pay a premium for the convenience. But it finally got me to 'chip' my car in my own garage. Would be cool if other tuners start heading in this direction as well for remote tuning.


You have an MED 7.5 ECU but I have an MED 17.5 ECU. Unless VW walked in and handed the MED 17.5 keys to C2 then there is no way in Hell that will work for my car.


----------



## thygreyt (Jun 7, 2009)

bobsuncle said:


> I think we'll be seeing roughly a 265WHP maximum unless there are commercial ITBs --but that's a LOT of sketchy napkin math, and not something I did any modeling on. 250WHP will happen for sure with UM E85 tune, cams, valvetrain, port&polish, internals, SRI, ram/CAI, headers, and 2.25" exhaust. Make sure to leave the stock cat b/c otherwise you'll lose too much backpressure.
> 
> This motor has yet to really give us it's true glory. There's about to be an EXPLOSION of aftermarket parts for the VW 2.5L.


Good luck.

Sent from my HTC Sensation 4G using Tapatalk 2


----------



## Kevin_FaKin_spLits (Aug 1, 2012)




----------



## Rabbidrabbitt (Mar 21, 2011)

bobsuncle said:


> I think we'll be seeing roughly a 265WHP maximum unless there are commercial ITBs --but that's a LOT of sketchy napkin math, and not something I did any modeling on. 250WHP will happen for sure with UM E85 tune, cams, valvetrain, port&polish, internals, SRI, ram/CAI, headers, and 2.25" exhaust. Make sure to leave the stock cat b/c otherwise you'll lose too much backpressure.
> 
> This motor has yet to really give us it's true glory. There's about to be an EXPLOSION of aftermarket parts for the VW 2.5L.


Why 2.25" exhaust? So you're saying if I go 3" and lose cat I will lose too much. This is like beating a dead horse here. With proper tune and supporting mods, you can see gains with larger exhaust and test pipe.


----------



## Rabbidrabbitt (Mar 21, 2011)

thygreyt said:


> Good luck.
> 
> Sent from my HTC Sensation 4G using Tapatalk 2


:thumbup: I second the good luck. Fred I think we both have seen the N/A pains LOL


----------



## bobsuncle (Oct 18, 2012)

Rabbidrabbitt said:


> Why 2.25" exhaust? So you're saying if I go 3" and lose cat I will lose too much. This is like beating a dead horse here. With proper tune and supporting mods, you can see gains with larger exhaust and test pipe.


One of the guys running 3" and test pipes lost power until he added a 2" muffler to increase backpressure. Not to.mention its illegal to cat-delete in many states.


----------



## bobsuncle (Oct 18, 2012)

Rabbidrabbitt said:


> :thumbup: I second the good luck. Fred I think we both have seen the N/A pains LOL


The n/a growing pains mostly revolve around pushing a car built for 6k to 8k rpms. With the new stuff coming out soon, the only real beotch left will be blowing accessories faster than normal.

There's still the issue of no custom on site dyno tuners for VW cars with MED 17.5 ecus --and that's a BIG obstacle that may never get resolved.


----------



## thygreyt (Jun 7, 2009)

Rabbidrabbitt said:


> :thumbup: I second the good luck. Fred I think we both have seen the N/A pains LOL


its not the pains, its the limitations... its the price.


----------



## bobsuncle (Oct 18, 2012)

thygreyt said:


> its not the pains, its the limitations... its the price.


Welcome to the hobby. It eats cash like Audrey 2.


----------



## mldouthi (Jun 26, 2010)

bobsuncle said:


> One of the guys running 3" and test pipes lost power until he added a 2" muffler to increase backpressure. Not to.mention its illegal to cat-delete in many states.


Backpressure is a made up word..... 

A lack of vacuum is what you are talking about and there are ways of designing/tuning a larger exhaust.


----------



## MasterJetti08 (Mar 1, 2012)

Oh lord...the never ending debate if the illusive back pressure has begun. Lol.


----------



## mldouthi (Jun 26, 2010)

:laugh: :wave:


----------



## Rabbidrabbitt (Mar 21, 2011)

bobsuncle said:


> One of the guys running 3" and test pipes lost power until he added a 2" muffler to increase backpressure. Not to.mention its illegal to cat-delete in many states.


So if I added a 2" muffler to my 3" exhaust it would add power? With just C2 N/A race file I was at 198whp Just had a little dip in torque, a proper tune fixed it. Back pressure ??:banghead:


----------



## MasterJetti08 (Mar 1, 2012)

You know honestly let's get some real discussion going about this. Not the usual "he did this and it made more power" or "he did this and I think he lost power" and all that bs. How bout we hear some factual evidence of whether back pressure is for real or not? Like maybe a dyno sheet of the exact same car on the same dyno with the only difference being a 2.5" exhaust and then a 3" exhaust? Or at least some valid arguements of why back pressure is good or not? This is something that has interested me for a long time because it seems to be such a big arguement everywhere in the automotive industry. It's not like we're talking about whether god exists or not. This is something that should be able to be proven by factual and "scientific" evidence. So how bout some?


----------



## mldouthi (Jun 26, 2010)

All I was saying is "backpressure" doesnt exsit. What people are talking about when they mention "backpressure" is vacuum. When each cylinder fires it creates a rush of gas which in turns creates a vacuum in the other cylinders when it reaches the collector of the header. You want this gas charge to reach the collector at the same time the next cylinders exhaust valve opens and therefore helps pull the gasses out of the cylinder and causing less work for the engine. To make this charge of air reach the collector at a certain point you can change to length of the primaries in the header or you can change the diameter or… even heat wrapping or coating will change this. X amount of air in a small tube will move faster than X in a larger tube, but hotter gasses move faster as well. So, for example you could have a 2.5in pipe move Y speed and a 3in wrapped pipe move Y speed also because of the temp difference. This is mostly about headers design but it has a lot to do with the exhaust design also. If a vehicle only has a header it will lose its vacuum on the other cylinders (Called Scavenging) because of the large pressure drop right after the collector. The same effect can be seen in running to large of an exhaust. Like running a 4in exhaust after the header will have similar effects to not running exhaust at all. The problem is, running a small exhaust can restrict the amount of air flow that will go through the engine. Since air is the fuel for the engine, you can only get as much in as you can get out. The amount of power a car produces in proportion to its displacement also plays a role in the exhaust size. Low powered car don’t need as large of an exhaust and will have a negative effect if a large exhaust is used. But a car pushing a higher power number and therefore a higher quantity of air they will need a larger exhaust. 

I hope this makes sense. I’m an engineer not a English major. 

This topic could fill a book. So this is only scratching the surface.


----------



## MasterJetti08 (Mar 1, 2012)

That was actually a very good explanation. So for an NA 2.5L, would you agree that a 2.5" exhaust is about right? At least for what we have available now? 2.5" seems to be what most people think is ok for the 2.5, unless you turbo it. Then you need a bigger exhaust because your sucking in more air, therefore putting more out correct?


----------



## mldouthi (Jun 26, 2010)

From what I have read, (I dont have personal experience) but from what we can get from these car power wise N/A (minus ITBs) 2.5 seems to be the largest you would want to go. But I could see going bigger would help with more power. Such as the ITB car or with Cams.


----------



## MasterJetti08 (Mar 1, 2012)

Yea that's what I'm thinking. Maybe once we get cams and all that good stuff 3" would be alright, but for the most part 2.5" seems to be what you want. I get what your saying about back pressure not being a real thing, it being a vaccum makes much more sense. Lol. I guess it's just one of those terms that people use without really thinking about what it actually means.


----------



## bobsuncle (Oct 18, 2012)

mldouthi said:


> Backpressure is a made up word.....
> 
> A lack of vacuum is what you are talking about and there are ways of designing/tuning a larger exhaust.


This is 100% semantics, which are in fact arbitrary. A lack of exhaust vacuum is called backpressure, but this is English --we drive on parkways.


----------



## bobsuncle (Oct 18, 2012)

mldouthi said:


> From what I have read, (I dont have personal experience) but from what we can get from these car power wise N/A (minus ITBs) 2.5 seems to be the largest you would want to go. But I could see going bigger would help with more power. Such as the ITB car or with Cams.


2.5" won't choke out cams IMHO. We'll see when the day comes, but I don't think it will.


----------



## mldouthi (Jun 26, 2010)

bobsuncle said:


> This is 100% semantics, which are in fact arbitrary. A lack of exhaust vacuum is called backpressure, but this is English --we drive on parkways.


Well I guess I should have said Backpressure is a word made up to describe a lack of vacuum in an fluid system (exhaust). *It is a word*.... just a made up one. 
You will not find backpressure in fluid dynamics book. But the word back pressure doesnt matter.

I was just being difficult.:beer:




bobsuncle said:


> 2.5" won't choke out cams IMHO. We'll see when the day comes, but I don't think it will.


You could be correct in your opinion. I never said it would, I just said maybe. Only testing, and in an ideal world math, could tell. I have not done either, thats why I said maybe 3".

Maybe one day someone will do a true same day dyno comparison.


----------



## MasterJetti08 (Mar 1, 2012)

Ill do it! If a company with the dyno will let me use it for free. Lol.


----------



## MasterJetti08 (Mar 1, 2012)

So what kind of power gains do you guys think we're lookin at when this IE can comes out?


----------



## MasterJetti08 (Mar 1, 2012)

So what kind of power gains do you guys think we're lookin at when this IE cam comes out?


----------



## mldouthi (Jun 26, 2010)

MasterJetti08 said:


> Ill do it! If a company with the dyno will let me use it for free. Lol.


haha, many have said that. The free dyno part if the hard one. I would do the same. 



MasterJetti08 said:


> So what kind of power gains do you guys think we're lookin at when this IE can comes out?


If I said a guess that would be all it would be... so I wont. We will all know soon enough.


----------



## MasterJetti08 (Mar 1, 2012)

No it's not soon enough!!! I need it now! Lol.


----------



## kevin splits (Aug 23, 2010)

I had AkronHP install my NGP drop in pistons and rods. I've put almost 5 thousand miles on the motor since then and I'm starting to get some chatter. Compression is fine, but in the long run I'll have to go to a over-bore setup and I'll probably get high compression pistons next time around. Running the lower compression with no boost is fine, mpgs haven't changed, the sound of the motor has, little bit of vibration but that might just be the mounts, now that its cold cold-starts are different seems to take a couple more cycles. 

UM has shown the motor will hold 450hp at the crank so might be best to skip this for awhile. I also don't really see the need to port and polish the head as it flows very efficiently. Past 7500rpm I would upgrade the valve springs to prevent valve float but with the new cams coming out I think that 250whp is possible n/a... I think...


----------

