# Drivetrain loss



## WASCALLY_09WABBIT (Jul 22, 2014)

What percentage drivetrain loss does the 2.5 have?


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## Reflex 2.5 (Dec 15, 2012)

For most front wheel drive cars, it's 14-15%. I saw somewhere that it's ~14.32% for the GTI/GLI, so it should be close if not identical.


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## WASCALLY_09WABBIT (Jul 22, 2014)

So roughly 15%, high balling.


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## Reflex 2.5 (Dec 15, 2012)

Yeah
Rough guidelines are 15% for front wheel drive, 20% for rear, and 25% for all wheel drive.


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## WASCALLY_09WABBIT (Jul 22, 2014)

So, with a Neuspeed P Flo, I'm ball parking here, I'm probably around 155-160 hp at the wheels. With the stock a air box sitting directly over the engine, it's hard to tell just how much that heated air takes away from overall power.


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## Reflex 2.5 (Dec 15, 2012)

Should be… I'm not sure what's worse with the stock air box, the heat, or the overall restrictive design.


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## WASCALLY_09WABBIT (Jul 22, 2014)

I'd say both. With the restrictive tubing looping directly over the engine, it probably works in concert to reduce power.
Only a dyno can tell for sure.


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## Rabbidrabbitt (Mar 21, 2011)

My 07 was 138whp stock when we did a base line run.


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## WASCALLY_09WABBIT (Jul 22, 2014)

That's the 150hp 2.5, right?


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## Reflex 2.5 (Dec 15, 2012)

Seems to be 170hp… I highly doubt these cars only have 8% loss at the wheels. That would be ~19% for the 170hp motor, and I just found something saying it can be 2-5% higher for slushboxes.

http://www.audiworld.com/forums/s4-...sses-through-fwd-rwd-awd-drivetrains-2820086/ percentages are listed at the bottom of the first post.


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## Rabbidrabbitt (Mar 21, 2011)

07 manual 150bhp stock


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## Reflex 2.5 (Dec 15, 2012)

WHAT!  sounds to me like VW understated the output a little. Based on average loss, that would put the actual output of the 150hp engines in the 160-165 range.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Reflex 2.5 said:


> Seems to be 170hp… I highly doubt these cars only have 8% loss at the wheels. That would be ~19% for the 170hp motor, and I just found something saying it can be 2-5% higher for slushboxes.
> 
> http://www.audiworld.com/forums/s4-...sses-through-fwd-rwd-awd-drivetrains-2820086/ percentages are listed at the bottom of the first post.


Automatics have more moving parts, so them having more drivetrain loss makes sense.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Rabbidrabbitt said:


> My 07 was 138whp stock when we did a base line run.





Reflex 2.5 said:


> WHAT!  sounds to me like VW understated the output a little. Based on average loss, that would put the actual output of the 150hp engines in the 160-165 range.


He stated his had 138 at the wheels. That puts it at 8% loss.


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## Reflex 2.5 (Dec 15, 2012)

Yeah, that's what I'd figured it to be… but I'm having a hard time believing loss is that low. Whether it actually is, or the output at the crank was understated, I'm not complaining.


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## WASCALLY_09WABBIT (Jul 22, 2014)

If that's the case for his, mine should be similar. Shouldn't it?


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## Reflex 2.5 (Dec 15, 2012)

Should be.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Them my whp would be 156, and with the air intake, 166-171.


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## Reflex 2.5 (Dec 15, 2012)

Just found this from USP's site (2.5 test pipe page::







blue line is a 170hp rabbit with p-flo intake.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Reflex 2.5 said:


> Just found this from USP's site 2.5 test pipe page::
> 
> 
> 
> ...


The top graph shows almost 150 hp he bottom graph shows almost 158 tq. Is that to the wheels?


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## Reflex 2.5 (Dec 15, 2012)

Yes


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## WASCALLY_09WABBIT (Jul 22, 2014)

I'm gonna be getting a Eurojet cat back soon. That should get me close to 170.


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## Reflex 2.5 (Dec 15, 2012)

These cars usually only pick up 5-10hp from a catback. You'd probably need a downpipe and tune to get in the 170hp range.
Here's the 150hp map:







again, the blue line is stock cat. Their car for these runs had intake, tune (+15hp crank. Keep in mind the actual output of the 150hp engine is probably 160-165hp), and catback. I figured at 138whp base + 10whp (intake) + 2.13whp (tune) + 6whp (catback) and got the same figures as USP, 156.12whp before test pipe.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Reflex 2.5 said:


> These cars usually only pick up 5-10hp from a catback. You'd probably need a downpipe and tune to get in the 170hp range.
> 
> 
> 
> ...


Absolutely. With the P-flo, catback, and tune, I'm probably around there. I'm using 93 octane as is, so I'll definitely get close. But, just to be sure, I'm gonna get it on a dyno once this is all done. That way, I'll be able to see exactly what I've accomplished.

EDIT

Also, I'll see if I can get the graph of that dyno so I can post it here.


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## WASCALLY_09WABBIT (Jul 22, 2014)

This bump is a question. I know some of you have the EuroJet catback already. Any thoughts on it? Opinions?
Didn't want to start a new thread for this.


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## dub_life91 (May 8, 2013)

WASCALLY_09WABBIT said:


> Absolutely. With the P-flo, catback, and tune, I'm probably around there. I'm using 93 octane as is, so I'll definitely get close. But, just to be sure, I'm gonna get it on a dyno once this is all done. That way, I'll be able to see exactly what I've accomplished.
> 
> EDIT
> 
> Also, I'll see if I can get the graph of that dyno so I can post it here.


been using the p-flo for about a week and love it. noticed a decent increase in throttle response and funnily enough my mpg's has gone up by 2-3ish


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## Reflex 2.5 (Dec 15, 2012)

^ Yeah, these engines seem more responsive to intake upgrades. The response and MPG bumps are the result of removing the German over-engineered heat sink VW called an intake.


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## dub_life91 (May 8, 2013)

Reflex 2.5 said:


> ^ Yeah, these engines seem more responsive to intake upgrades. The response and MPG bumps are the result of removing the German over-engineered heat sink VW called an intake.


if it is a heatsink then i could use it on my computers cpu! that would cool it right down


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## Reflex 2.5 (Dec 15, 2012)

^ Hook a water pump up to it and rework the piping to recirc it… should work. :laugh: A heat soaked plastic maze isn't the best choice for an intake though.


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## dub_life91 (May 8, 2013)

Reflex 2.5 said:


> ^ Hook a water pump up to it and rework the piping to recirc it… should work. :laugh: A heat soaked plastic maze isn't the best choice for an intake though.


hahaha that would be a fun project for sure! yeah it was a weird idea to do for an intake


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## WASCALLY_09WABBIT (Jul 22, 2014)

And the stock exhaust with not one, not two, but three sound mufflers. Can't wait to get this Eurojet catback on it.


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## Reflex 2.5 (Dec 15, 2012)

Technically four if the car has an actual resonator (I'm counting cat, mid, and rear muffler), five if it's a Cali emissions car. All in all the stock exhaust actually flows pretty good for what it's worth though.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Reflex 2.5 said:


> Technically four if the car has an actual resonator (I'm counting cat, mid, and rear muffler), five if it's a Cali emissions car. All in all the stock exhaust actually flows pretty good for what it's worth though.


Ah, I wasn't counting the cat. Yeah, counting that it's four (cat, resonator, mid muffler, and rear). 

I've been told it flows really well for being stock, but it's just not the same without some sound note to cap it off. After a fair amount of research, I'm going with the EJ catback. Dyno graph to show the numbers, audio to prove a lovely sound, and it's fairly priced. AWE was a close choice, but the decision has been made. :thumbup: I will be buying it in a few weeks, and I will be looking at a tune shortly after. So far, IE has my vote on that. The shop UM has is waaay too damn far to make it considerable.


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## WASCALLY_09WABBIT (Jul 22, 2014)

Looks like I'll be getting this exhaust early. 

I've been taking my time on modifying, partly due to making sure I'm getting a decent bang for a decent price. I'm not building a racecar. I don't need the best parts available.
Mostly due to money constraints. I'm working full time supporting my mom and myself, while trying to have some fun with what I've got left over. 

Well, I earned way more than I expected to this week, so I'll be ordering the EJ exhaust come Monday. Bills come first, then fun. :thumbup:

And, if it comes in before next weekend, I'll be putting it on that Saturday.

I'll record videos of the exhaust sounds before and after, so that anyone who is trying to decide which exhaust to get will have an idea where the EJ sits.


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