Toyota Yaris Forums - Ultimate Yaris Enthusiast Site
 

 


 
Go Back   Toyota Yaris Forums - Ultimate Yaris Enthusiast Site > Technical Forums > Forced Induction Forum
  The Tire Rack

Reply
 
Thread Tools Display Modes
Old 03-19-2015, 03:03 AM   #1
alias06
 
Drives: 2008 Red Toyota Yaris
Join Date: Mar 2011
Location: MN
Posts: 76
Custom Supercharger Possibility???

I am debating about building a relatively "cheap" supercharger for my 08 liftback. I understand that their is the Blitz supercharger kit made for the Yaris and is more or less a bolt-on setup. My idea though is to have a custom supercharger setup instead. With the research that I have done, I know that I'll need a blower of some sort, larger injectors, custom intake manifold or custom piping to the stock manifold, custom brackets to hold the supercharger, belts, etc. The reason as to why this idea came to mind was the fact that I have been able to source a few Eaton M90 superchargers for roughly $100-$250. I understand that the CFM the supercharger is capable to push is much more than needed for our little 1.5L as the M90 was designed for engines of greater displacement, but since it is relatively cheap (and cheaper than a M45 or M62) I figured that it might be worth the while. I also understand that the physical size of the supercharger might make it impossible.

The horsepower goal that I have in mind isn't crazy but around 120 whp is what comes to mind or whatever 5-6 PSI of boost can get me without heavily supported mods. With some mathematics I have came up with that our 1.5L is roughly 91.5 cubic inches with an estimated VE of 80 at 2500 RPM our engine would breathe in roughly 53 CFM of air while with a VE of 70 at 5000 RPM the CFM would be about 93, according to the equation #2 found from http://www.ehow.com/how_7953457_size...ercharger.html

Assuming that I am making 90 whp and want to reach the 120 whp goal and that everything else is proportional it appears that about 5 PSI is the magic number to get there by using the equation in step #4. The needed pressure ratio then can be determined as 1.34, using this pressure ratio and multiplying it by the calculated CFM from earlier to get compressor CFM I get 71 CFM @ 2500 RPM and 124 CFM @ 5000 RPM with the combination of equations #5 and #6.

With interpolation and the compressor map of the M90 (5th Gen) I should fall within the 55-60% efficiency of the compressor. By converting the CFM requirement to M^3/Hr as the map I get a range of 120-210 M^3/Hr (I understand that this doesn't fall in the compressor map and it is interpolation which can be totally skewed and way off), but it seems that I should be able to spin the supercharger at roughly no speeds higher than 4500 RPMs. (I know that the efficiency isn't the greatest and there are other chargers out there that would work better for the application but cost is the biggest driving force in this theoretical project)




Now my question is if anyone could double check and let me know whether or not my calculations and assumptions are correct.
I have found an old thread showing where a Jimze charger (M45) was used (http://www.yarisworld.com/forums/showthread.php?t=43995) and the pre-hack DIY Eaton Supercharger thread which didn't seem to come to completion (http://www.yarisworld.com/forums/showthread.php?t=10720)

The idea is to basically replicate the same setup as with the Jimze supercharger but with a different blower and stock engine, is there anything else that I am missing? Thanks in advance...
alias06 is offline   Reply With Quote
Old 03-19-2015, 06:31 AM   #2
CTScott
ULTIMATE
 
CTScott's Avatar
 
Drives: 09 5dr LB, 2x 08 3dr LB
Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
Your math looks fine. The typical biggest reason to not do a DIY supercharger is the cost of making a custom manifold and necessary brackets to support the significant weight of the supercharger with the torque of the belt pulling on it.

I ran into an Ogura recently off some Nissan vehicle that has a round pipe on both the input and output sides, which would make plumbing it to the existing intake manifold a whole lot easier, but like most, it has no snout, so you would have to figure out how to mount it over by the alternator. The blitz setup of flipping the alternator upside down and dropping it down about 6" lower than it sits would definitely help.
__________________
CTScott is offline   Reply With Quote
Old 03-19-2015, 06:43 AM   #3
CrankyOldMan
2ZR swap. DO IT! Ask how!
 
CrankyOldMan's Avatar
 
Drives: 09 Meteoric Metallic HB
Join Date: Feb 2011
Location: West Michigan
Posts: 2,333
Looks like you've done quite a bit of homework! Good on ya. I think you'll have to do some ratio work to get the right sized pulley, but that's how you will control the volume flow. I.e. make sure the ratio of crank pulley to supercharger pulley won't put you over your peak psi at redline.

The thing that makes the Blitz a bolt-on solution is that it comes with a piggyback fuel controller. Without it, the ECU will fight you every step of the way--trying to keep the AFR right at the stoichiometric peak (14.7). That's too lean for more than a few psi, which means your connecting rods will suffer an untimely death. Larger injectors will protect you when you're in open loop (wide open throttle) but short of a piggyback, you can't compensate for closed-loop.
CrankyOldMan is offline   Reply With Quote
Old 03-19-2015, 10:39 PM   #4
CoryM
 
Drives: 2009 5-door, 5-speed
Join Date: Sep 2011
Location: White Rock BC
Posts: 687
I think you'd do better to run the M62, which can be had for pretty much the same price as a GenV M90. Saving $100 by putting a M90 is probably not a good investment. Also if you haven't, check out the M45 from the Mini cooper. They are about the same price here (could be just here. Popular cars.). The M62/M90 are a more reliable unit though.

For tuning, consider Megasquirt if cost is a factor.
Cheers.
CoryM is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
List of Boosted Yarisworld Members whooppee777 Forced Induction Forum 262 11-23-2022 05:49 AM
What real gains from supercharger? xb visitor Performance Modifications 9 07-30-2014 08:46 AM
Blitz Supercharger: Custom Inlet Pipe and intake wildmongoose26 Photo-Video-Media Gallery 10 03-21-2014 11:20 AM
Converting from Custom Wheels back to stock!!! daddz07 Wheels, Tires and Suspension Forum sponsored by The Tire Rack 11 09-23-2010 08:45 PM
Custom tags and custom vinyl ellenbetty Cosmetic Modifications (Exterior/Interior) 9 09-11-2009 03:13 PM


All times are GMT -4. The time now is 02:40 AM.




YarisWorld
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.