Just would like to help fellow m157 owners understand they have options and do not have to spend thousands of dollars on over priced parts but yet still attaining just about the same power levels as those that do. Nothing wrong with buying parts at all so for those who did I’m not in anyway saying you shouldn’t have.

INTAKE!!
Upd spacer works well with k&n or whatever filter you prefer but removing the inner slates definitely helps flow also at the bottom of our stock intakes there is a small hole idk why it’s there but I plugged mine up. Buy some heat gold heat reflecting tape and place it on the bottom of your intake boxes it will dramatically help keep the intake boxes from being heat soaked from sitting on top of the engine. All these small steps help


MIDPIPES ! For use off road only ��... As we all know they are super over priced for 2 stainless steel pipes with o2 bungs. So here is your option

Remove stock downpipes which is a total of 8 bolts and and removing the o2 sensors. Will take a total of 2 hours if it’s your first time, took me 1.5 hours to remove the downpipes gut the cats and reinstall. If your tuned then you don’t have to worry about the check engine light, if you aren’t then you can go to any auto parts store and purchase an o2 sensor spacer which is less then $10 bucks for 2 . The first o2 sensor doesn’t need one but the second o2 sensor will , it’s very easy, screw the spacer in then o2 into the spacer. some of you may get lucky and the light may not even come on.

outcome. Very responsive, you will definitely feel the difference immediately. Faster spool, crispy throttle response, and the entire power band is stronger. But dyno reads 20-30hp 20-40tq. Will be hitting the dyno for proof tho for factual numbers. I’ve personally went from gutted cats to legit downpipes and did not gain any power from when I was just gutted cats,, so that power lose from the so called exhaust turbulence that you would get from the cats being a bigger diameter back into a smaller diameter seems to not affect a turbocharged motor/exhaust. For N.A I can’t say. Remember I’m talking downpipe not true turbo back or what some may call midpipes. That is completely different. Obviously a true turbo back will yield power. Also as far as sound if you remove your resonator and your cats with stock exhaust still in place you may get that lawn mower choppy sound. I personally have magnaflow 3” single straight through mufflers and have no chop sound at all, sounds smooth and deep. Seems the magnaflow smooth out that choppy sound.

METH INJECTION!!
pre turbo injection yields real power gains without being tuned for it. If you check my dyno post with stage 1 you will see how my meth run pre turbo gave me more power mid to top end, and I’m only injecting issuing one 175ml nozzles per side of the upper intake boxes without issue. I haven’t logged IAT but the dyno graph clearly shows my timing isn’t retarding. For more info on pre turbo injection, google (pre turbo methanol injection). Some of you are spraying massive amounts of meth pre intercooler which is proven to be the least efficient place. Also you can purchase a complete 3 gallon trunk mounted universal methanol kit from AIS or devils own for way way less then what some others are pushing the kit for, Note when spraying pre turbo it is best to use a higher meth content. I but m1 pure methanol and do a 90-10 mix


AWIC expansion tank upgrade!!
For those of you that have the new separated system. You can dramatically drop temps by increasing water volume. Buying an aluminum universal tank and reroute the lines that go from the stock intercooler into the tank. You can install a decent size one on the front passenger side next the the stock coolant expansion tank or you can run the lines under the car and place a 3 gallon tank where the spare tire goes. Temps will be much more stable and when your at the track you can throw ice in the tank, I made a switch that allowed me to turn on my pump to circulate the ice water to freeze up my intercooler before my run, that way my intake air was as cold as possible. This was on another vehicle but the same exact idea.

 

Spacer






Pre turbo location


Gutted cats . Off road use only

 

A few things. I personally don’t think there’s enough gain to warrant the turbo back kit over the DPs. There isn’t any room to get the spacer in on my downtubes. Mine are aftermarket but if the OEM location is the same the spacers may not work. Second, spraying water/meth pre turbo typically requires a higher concentration of, or pure meth. Most packaged kits do not have a high enough quality of parts to accommodate the higher concentration so people need to plan for this and may need to piece together the correct meth system. Either way, please don’t pay those idiotic prices for that fugly Weistec kit!

 

yes thx I forgot to mention when running pre turbo it has to be a higher meth content. I am using 90 meth 10% distilled water. And as far as true turbo back , I haven’t seen any before and after turbo backs so I wouldn’t doubt if the gain is minimal. I can only mention what I do know. They are so expensive plus the motor needs to be removed. With all that work I want 50hp minimum gain lol

 

Slow junk

 

sorry your car is slow junk, use some of my methods maybe it will help

 

Lmao. What's up E!!!

 

lol I knew it was someone I knew. Your car is next brotha. Will be at the shop Monday to remove your ecu and **** it to EC. Get the meth kit I’ll help you install it. Let’s get that cl over 600

 

love seeing people think outside the box

 

An ironic note, I had a modified turbo car when I lived in Cali and I hollowed out the cats like you did. I wasn’t sure what to expect when it came time to get the car smogged. Since it was tuned properly, it passed with better numbers than previous years!

 

thats always good. Passing with better numbers lol. But usually the tune knocks out the second o2.. but if you listen to vendors they will tell you everything negative about gutting cats. But I can’t lie down pipes look so pretty. But the only person who sees them is the dealer when they change oil or jiffy lube 👀😂😂😂

 

My only concern with hollowed cats is creating turbulence when compared to a straight downpipe. But even if there is some turbulence it still has to flow better than with the catalytic matrix in place.

 

turbulence usually affects N.A cars, because it does use exhaust scavenging, but I have done dyno comparison from going to straight pipe catless from gutless cat, and it showed no gain at all. 2 cars tested were both 350whp Audi-vw. The exhaust side of the turbo has so much force coming out I think it cancels out any turbulence that may be accruing. Sound may be the only difference. I just don’t feel the 2,500 for downpipes is worth it. Again from the turbo back I’m sure there is a decent power to be had. Because the diameter from the turbo down is changed . But even that in my opinion not worth it. Cost way to much to remove the engine to get them installed, the power gain vs dollars is not there. Now if you are upgrading turbos!!! That’s a diff story.


side note. I’m waiting to hit the dyno to get my EC stage 2 numbers . But I have numbers showing when I went catless after my first EC stage 1 dyno. That way I can record factual gains. That way us m157 owners know what we are gaining when going catless without being tuned for it

 

I think the Weistec modular mid pipes aren't a bad deal $1500, I would rather keep my cats when I sell the car and then sell the midpipes but to each his own

 

high flow cats aren’t that expensive. Also don’t forget what it cost to remove the motor to install mid pipes. It would be cheaper to buy used oem cats. Much cheaper

 

Turbo back down pipes might not yield huge gains, but if you thought your turbo spool was loud with just downpipes, its even louder with turbo back dp, worth it just for that. Also the stock turbo pipes are a very awkward shape and its definitely not the most efficient, so any improvement is helpful. If you are not 4wd then removing the engine is retarded and weistec's instructions are way too complicated. Most useful thing were the torque values.

 

HI 5 to the DIYers! There's potential to be had without spending a bunch of cash! my car made over 600hp to the wheels on a mustang dyno with no tune to prove it! Keep it up!

 

I’m thinking about Weistecs modular mid pipes , keeping my stock downpipes and resonator how much louder will this be ?Will I get more turbo noise ?

 

The mid pipes seem pointless to me, and over priced. You get 2 small pipes for 1.5k and you still have to buy their downpipes to be plug and play. Better to just get regular downpipes if you are going to leave the stock turbo pipes.

 

Nice, what mods? And how much were the gains from baseline?

 

shoutout to all TTMERC. Gave me a couple of good tips that worked really well. I prefer to take advice from DIYers. THey are hands on and have went through the pros and cons . People stop taking Everything these vendors spit out as golden. I personally run a body shop and I tell my customers all their options and how to save, instead of trying to give them the only expensive option. Guess what they come back, and come back. You have to tell people the truth, eventually they will find out all the other options and pointless upgrades and remember you baited them, and they will not return. I’ve been wrenching since I was 15 so I like to find other ways

 

You get the 2 small pipes and the pipes that replace your cats to the resonator but have the option to get downpipes in the future if need be, $1500 not much different than any other company , plus Weistec make real quality parts

 

You don’t have to drop the engine to do midpipes only downpipes so you can drop the cats in one piece then bolt up the midpipes , 1 hour tops with a lift

 

arent the mid pipes the terminology used to describe from the turbo hot side that goes over the motor mounts and meets the downpipes ? Maybe I got it backwards ��

 

I was thinking there’s actually 3 sections of the exhaust system , Downpipes (short pipe from exhaust side of turbo) , the Cats(midpipes)bolt to the downpipes , then the resonator and muffler section