rappit4

Hello guys!
I know this generally have been asked a lot but I just want to have your personal opinions on the subject about my car.
I think as of now the most restrictive component on the build could be the stock pistons.
This is a completely rebuilt VVT engine in a 96 NA chassis. I've got TA Techinx con rods and brand new OEM 0.50 ovesize pistons with ACL race bearings. The head is ported and all the valves, springs, stem seals etc. have been replaced with new oem ones. I've the boundary oil pump and a fluidampr harmonic balancer.
I've got a cometic head gasket with arp head studs, I also have a coolant reroute and a mishimoto alloy rad. My injectors are Bosch ev14 640cc. I've a mishimoto intercooler and a forge BOV.
My turbo is a Garrett GT2860RS with a kraken manifold and a full 2.75" exhaust system with a magnaflow muffler and a sport cat.
The ECU is a MS3 with the expansion panel.
I've got the Type 1 Torsen diff with a 4.1 ration and a 6 spd tranny (I know its pretty short like this hoping for a 3.6 or a 3.9 diff).
My tuners main concern is that the stock pistons CR is too high and he thinks that it would not sustain anymore than 250whp, which I am a bit bummed about because I was hoping for maybe 300 at the wheels.
What do you guys think? And also do you think there could be some more weak point that needs to be replaced before I start assembling everything except the engine?
Thanks in advance!

WigglingWaffles

More than 4 but less than 2,000

Skamba

Doesn't Hungary have decent e85 availability?

rappit4

Unfortunately not anymore. There is no more e85 gas stations left.

Skamba

That's a bummer, I remember that they had it a few years ago when I visited. At least get the highest grade fuel you can get, as it makes a big difference.

Based on what I've read on these forums so far, I think you should be able to go over 250 whp. Not sure if you'd be able to get to 300 though.

rappit4

Yeah that is fair enough. I mean it would be nice to go for 300 but 250 should be plenty. And at least with these safety components hopefully it will be pretty reliable. Btw the fuel in Hungary is really high quality especially the 100RON Premiun ones.

rwyatt365

I'd think that 250 whp (+/- 20) would be a reasonable estimate. I think that your limiting factors are the turbo, injector size and exhaust system (even though 2.75" is better than my 2.5"). Think of your engine as an air pump - the higher the flow, the higher the peak power. If you can flow more air (bigger, or better-flowing turbo, good flowing exhaust manifold (the Kraken is good) and bigger exhaust (up to a practical limit) then you can theoretically make more power. Of course you have to have the fuel to support that higher air flow, thus the bigger (or better-flowing) injectors.

rappit4

So you would go for a 3" system? Many people recommend the 2.75 instead of the 3. Isnt the 3" too droney and loud for daily usage?
Also do you think if I trade my 640 with a 1000cc the turbo would still have some potential left?

borka

iTrader: (1)

i made 309whp in my ff630 cc injectors, so injectors are fine.

why did you install new stock 10:1 pistons?
if you were planning to turbo, better to install stock pistons out of an NA miata, they are 9:1

i have a rods only rebuild, with stock 94 pistons on my vvt motor, untouched 200k mile head and made 309hp.

rappit4

Because I wanted to stay N/A and then I got an offer for the con rods while the engine was still apart but I have already got the stock pistons and then gone down the rabbit hole

rwyatt365

Many people complain about the sound from a 3" exhaust (unless they've supplemented it with a monster Magnaflow). As I said, I have a 2.5" exhaust so my setup doesn't compare. BUT, I'm a glutton for punishment (no A/C, no PS, 245 tires on a Xida suspension w/ 700/400 springs and AWR engine mounts - that I DD), so if it relates to comfort, or NVA...DON'T follow my advice.

Regarding the injectors, I'm running 650cc FIC injectors and at 250whp, on 205kPa of boost, I'm at about 80% duty cycle. So, there's still some room for more power, but not much. IF I weren't poverty-stricken (kinda), I'd be on 1000cc ID's right now - for the extra headroom.

HowPrayGame

The Magnaflow to use with a 3" system is the Magnaflow 12589

rrjwilson

Your tuner is right.
CR really needs to be measured to be sure but you should put it pistons and ring in too.

Everything else you have done seems ok but 330bhp or 300whp would require a new fuel pump too which isn't mentioned.

Better flow = more power.
2.75" < 3"
I appreciate the trade off for volume though.

rappit4

What I'm afraid of is that the cylinder wall should be honed again for the new rings to seat properly right? That would bump the cost pretty significantly. :(
Yes the 255 walbro pump is on the list!
I think i'm going to trade the 2.75 for a 3"