Hi all, I need your advice.

So long story short, I bought a used evo 8 about 2 years ago. At the time it had an intake and cat-back exhaust. I bought it from a mechanic who assured me that it wasn't "returned to stock". Fast forward about a year and getting it up to ~102K miles and driving it every day, I go to get it tuned with an ebc, walbro 255 pump, and new DV (OEM one was shot). Get it on the dyno and it's running very lean. Come to find out that it was a hose from a boost gauge that was removed and never put back together properly (should have seen that I know). So I had been driving it lean for a year...My tuner said I'm lucky it didn't blow up, but if it makes it off the dyno then it's good to go. So it made it off the dyno and I have been driving it with this setup and tune for about a year and am up to 105k miles with no problems at all. My question to you all is, do you think the damage done while driving it lean for a year is too much? Is it a ticking time bomb? I would love to get it up to ~450whp but is that going to be a recipe for disaster? Any and all advice/opinions is greatly appreciated.

Thank you

 

IMHO, 450whp (DynoJet or Mustang?) is pretty stout for a stock, non MIVEC 4G63

I would do a compression check & if all reads OK, I wouldnt worry too much about it

 

Yeah I think the first order of business should be to get an idea of what shape the engine's in. In addition to checking compression it's probably worthwhile to measure oil pressure using the procedure in the service manual and see if those values fall within spec. I wonder if you might be able to glean some insight about how much damage the detonation did to rod bearings based on those values.

 

You can assess the damage by doing a compression and leak down test. It's likely fine. You could also pull the oil pan and pull the rod caps to inspect the rod bearings. Rolling new bearings in at that point wouldn't be too difficult, just check clearance with plastigauge.

 

MinusPrevious you think 450whp is too much? I don't really care about the numbers thats just around the power level I'd like. It is a mustang dyno too, I read 259whp and 225tq after the mods I listed, but they had to keep it low because I was on the verge of needing a new clutch and was getting heat soak from an inefficient intercooler. I'm going to do all of those tests asap and if everything checks out I'm thinking intercooler, test pipe, head studs, injectors and maybe the FP 71HTA CHRA or the FP green or red?

 

All depends on how hard you want to squeeze the stock block. If youre looking for longevity & relatively trouble free, I would shoot for no more than 400 dyno jet WHP /WTQ

Others may disagree, but if youre OK w/stressing the stock block & drivetrain at its limit, 400 Mustang pwr would be way up there IMO

 

No need for head studs. With proper tuning, the connecting rods will let go first if torque is pushed too far.


I would do cams and a 71hta. With E85, you'll get over 400whp, and the car will be very responsive and fast.

 

I am definitely not chasing numbers, I am much more concerned with longevity and reliability. So you guys think cams and 71HTA for about 300-350whp on a mustang dyno is reasonable?

 

Some people worry too much, its rather funny to read about.

 

Like the others said, check the engine then go with a plan. I'd want to know the health of the engine first.

Otherwise, there are many posts on here about people daily driving their Evo's with 300 + HP for years with no issues. Do some reading on those and then compare to your car and goals.