erioshi

It sounds like you are going through the process I was involved in when trying to decide what to do with my rebuild, For me the question was do a "almost stock" build or go with something much bigger? I wanted 400+ mustang whp but didn't want to loose the car's street friendly driveability, good torque and fast spool. For me the choices seemed to be a new gen twin scroll gt35r & possible stroker build for big power (since it wouldn't really cost much more then a 3076 based set-up) or keep the car close to stock and use only parts that were almost part for part OE replacements.

I had already invested in a mix of parts that were about 50/50 each way - the head work, oversized valves and uber high lift Piper cams said go big, but my 3" OE replacement TBE, ported stock intake & exhaust manifolds and modified K&N intake said keep the car close to stock. To go big I would need a new intercooler, piping, turbo, BOV, wastegate, etc along with some custom exhaust parts and my rebuild parts. For a stock like build I needed a Green, smaller cams (I'll explain below) and some way to increase boost like meth injection or e85. Either way I would need to add more fuel with bigger injectors. Another question was engine management - how well would the OE ECU adapt to a large turbo set-up. The exhaust was an issue because my 3" TBE connect to a down pipe connection in the stock location like most turbo kits, it essentially combines the down pipe & pre-cat pipe with a one piece flex pipe.

Now for some OT:

I'm not sure why 400 whp is such a magic number in Evo land. In the MR2 world (another place I mod) the magic number seems to be 300 whp on a dynojet - and again it's usually just out of reach unless you build the car just right or spend enough money to build a 500+ whp car. There seems to be a "magic number" like this in just about every commonly modded car community.

A good number is 10:1 - 1 hp for every 10 lbs of car. A car with that power to weight is usually considered really fast. A ratio of 7.5:1 is crazy fast and a ratio of 5:1 is beyond description unless you spend alot of time in race cars. Even at 10:1 most cars start braking OE parts when driven hard - better ratios brake parts faster - like my blown front diff & stretched rod bolts... The number crunching melts a bit because I'm using a steady value of 125% to convert whp to crank hp; Mustang numbers. Not perfect but it gives us some reasonable numbers to compare.

More ratios:

220 whp = 11.6:1 ratio - stock Evo 8
240 whp = 10.7 ratio - 108% of stock Evo 8 - stock Evo 9
340 whp= 7.5:1 ratio - 155% of stock Evo 8 - your car
385 whp = 6.6:1 ratio - 176% of stock Evo 8
400 whp = 6.4:1 ratio - 180% of stock Evo 8
500 whp = 5.1:1 ratio - 227%of stock Evo 8

So what does all this mean? The ratio is the best way of showing how much faster you car will feel. The feel doesn't exactly match the ratio but it's a solid measure of real world performance gain. A 400 whp FP Green set-up is 117% of you current car so the jump in power will feel much smaller than your first jump - for comparison that was a 143% increase from stock Evo 9. What all of this really shows is that to keep getting that "much faster" feeling it takes significantly more power at each step. It also shows why the first 100 whp bump in power feels much faster than the second.

Back to the original topic:

With each of the "big power" mods I had added to my car, it's day to day driveability had gone down a bit, until the car was no fun in traffic and it was starting to have other driveability issues. I have built a big HP car before, and eventually that car was really fast, but no fun to drive - exactly what I didn't want the Evo to become. What I decided was that I loved the way my stock Evo drove, it just needed a bit more power. The end result was that I decided on a near stock build with good power that I would enjoy driving anywhere.

I hope all of this helps again - anything else I can help you with? Oh - if you post any of this in the general forums please credit me. I haven't posted much lately; been kinda busy.

sokaroza - hope you don't mine I posted this reply to your PM in the forums. It seemed like good info to share.

ronitlancer

iTrader: (2)

good read

RsxTypeS-2-Evo8

iTrader: (16)

Nice....

tkdabb22

iTrader: (2)

i think that the way i want go to

Ludikraut

iTrader: (17)

Good thoughts. I have a few comments/questions...

- why do you feel that a 3" exhaust is not adequate at the 400-500whp level?
- IMO the 400whp level is a big deal for Evos, since it's not that easy to achieve for a VIII on pump gas and/or with only bolt-ons
- I agree that 5:1, i.e. any Evo over the 500whp mark, gets pretty hairy for street driving

l8r)

SLVRNBLK

iTrader: (169)

I hear you! I share the same feelings. Great information!

SLOWRREX

iTrader: (1)

400 is my goal as well..But, i have an evo 9..I put down 321hp,and 316tq with only an intake,tbe,mbc,and a tune..I am looking into cams,and maybe meth next..And finally a turbo upgrade..We have 93 octane here,and also have gas stations that sell 100 octane at the pumps..I dont really want to go big turbo,so it looks like the green is probably going to be my choice..I guess my question is,Are my goals realistic??I am hoping so,but,i also dont want to lose the driveability of my car..I really do enjoy it the way it sits now,besides the slipping clutch..Different story all together..Any suggestions in my quest??Thanks for some possible insight..Justin

mplspilot

iTrader: (7)

Good read indeed!

Evo8Emperor

iTrader: (12)

A nice read indeed. Now to decide what to do with that info. But I dont really agree with that the evo becomes harder to drive with the more mods you do. The only real problem comes when you go bigger the a 35r on a 2.0 i think. With all the TS tech. popping up and all the ways the keep your car running on the stock ecu to maintain drive ability like stock theres plenty of options out there i think to keep a nice fast DD. but thats imo.

sem23tex

iTrader: (6)

Nice read! Thanks for taking the time to post.

InitialE

iTrader: (5)

Interesting & informative. Can anybody guesstimate how these weight/whp ratios translate into 0-60 numbers, at least in terms of ranges? Say 10.7 (stock Evo 9) seems to translate into 4.4-5.1 secs. Where would 7.5 take you?

erioshi

One of the big things I wanted to highlight was there there is really going to be a very small difference in feel between a car with almost 400 whp or one that does have 400 whp. It's usually not worth spending alot of money for just a little more power.

I don't feel the Evo does get that much harder to drive with additional power, especially when compared with any 2wd car. However with enough power you do start to have traction problems - and they come on sooner than most people expect. Even with a good set of coilovers and sticky tires I ran into front end wheel hop on straight line acceleration with essentially just a Green, cams & e85 (plus the supporting bits) while I still had the boost turned down to about 18 PSI. The wheel hop was violent enough that now I'm pretty sure my front diff is toast. I'll be pulling it out of the car to check things out when I have a chance later this summer. Looks like I get to miss more track events with the Evo.

There is a big difference though in grinding through an hour's worth of stop & go when you get caught in the wrong place with a stock car vs one that is more prone to stalling & has low speed surging and a touchy clutch. None of those issues are a big deal individually, but when you add up several of them a can can become a grind in the wrong kind of traffic.

Also I want to clarify the 3" exhaust thing - I wasn't disputing using a 3" exhaust at all. In my situation MY 3" exhaust would have needed some custom pipe fabbed up to make it work with most typical big turbo kits. That's all.

Vapor

iTrader: (4)

love the original post. Thats kind of the same philosophy that I've taken in building my Evo. I've been building fast cars for well over a decade - making HP is just a function of cash and know how, its not hard. What is hard is maintaining a car that is civil to live with. My method I like to call "enhanced OEM" - like stock, but better. I've just tried to take the approach that drivability should never be sacrificed, because thats when you start to grow weary of driving the car.

In general, 400whp for any 4 cylinder is fast and on the verge of no longer being streetable.

SpyderTB

very nice thread

Ludikraut

iTrader: (17)

I agree with the drivability comments. It's amazing how a few little things can add up to take your car from being a blast to drive to being a teeth-grinding experience. Fortunately in my case it's swung back towards the fun-to-drive area... now if I could only get a good clutch...

l8r)