Is this 1.6bar overboost in the midrange or 1.6bar all the way? I'm just saying what's recommended by professionals. Things take time to fail, you can be lucky. Are you trying to say that you know of people running 1.5 or 1.6bar throughout the rev range with no internal mods? I wouldn't do that for long.
I haven't gone for a boost upgrade myself and am still making comfortably over 300bhp, just with breathing aids.
Cams. I've seen 346bhp with only 1.3bar. This was using a de-cat exhaust system with Shell Optimax 98RON fuel and I doubt you'll get anything like 350bhp with 93RON fuel at 1.3bar.

 

Ah, with cams, not a problem, I thought you were looking to get that from your "Stage 1." And yes, there is quite a few Evo's that run 1.5 bar, but obviously not through the whole rev range, no car runs the same boost through the rev range. The standard turbo wouldn't hold 1.5 bar until the limitter anyway. Quite normal is to build up boost to whatever 1.5-1.6 and then level off to 1.2 or something around there. Still, I don't think the bolts will be needed, or have you ever heard of big-eng bolt failure on an Evo? Also the conrods are good to beyond 1.6 bar, I think generally it's good to replace them at around 1.8. There's cars that run that boost WITH new pistons but WITHOUT new conrods and have done so reliably for years. I think it's also quite common in the US DSM 4G63 engines.

 

I think we're on a different wavelength here. When I refer to 1.3bar as being the limit for the standard conrods, I'm talking about holding 1.3bar to 7000RPM. It's how much boost you hold at the top end of the rev range that determines the power output of the engine. At lower engine speeds, like the midrange, the reciprocation of the forces involved obviously isn't as frequent and higher boost can be ran without exceeding the limits of the conrods. I've seen a warped standard conrod from an R33 skyline who tried running 1.4bar and 620bhp with a set of mines turbos - not pretty, they advised him, he didn't listen and now they keep the item as a warning to others. A guy from a magazine got the same conversion done but had to wait for the Trust titanium conrods. They told him not to take it over 6000RPM in the mean time and very wisely he didn't.

 

A live test. Can't say fairer than that.

Have you no internal modifications at all? Do you quite regularly use the full 7500RPM? Keep me posted.

 

Okay. Send a quick post when it breaks.

 

It won't break!!! Like I have said before, tell me about a big-end bolt failure on a Evo 4G63, then we can talk. But obviously you haven't seen/heard anything like that yourself so there's no proof for your side of the story. For our side there's quite a few...

 

People don't tend to go round broadcasting it when it happens to them. This advice isn't my advise really, it's the advise of Torque Developments International, JUN, several magazines, you name it. I'll quote the January 2002 edition of 'Cars and Car Conversions - CCC':
"Replacing the ARP bolts... will give you the flexibility to increase boost to 1.3bar before strengthened conrods are needed... If you are to exceed 1.3bar boost, Ralliart recommends the above engine strengthening mods before turning to the turbo for answers."
You can get away with exceeding this for a while but it's a question of reliability. There's no proof for your side of the story either. You have one person who's running 1.4bar with no internal mods but no proof of how long it will last. The bottom line is that you're better off with 350bhp and a guarantee slip from a professional than a 400bhp DIY job and crossed fingers. If you insist on a DIY job, at least listen to the professionals. As far as I'm concerned Ralliart are the final word but you run whatever boost you want. Run 1.4bar. Run 5.4bar. Even bolt on a 650bar Rolls-Royce multi-stage barrel compressor if you like.

 

Why does everybody decide to go with the interals AFTER the fact. Fer me, I'd rather have a car that I know will run safe at higher boost before I even THINK about goin fer more bars.

Quick analogy....half the people I sell cell phones to buy plans that give them a lower amount of minutes than they think they'll use. If you go over it costs you $0.40 per minute. The next plan up only costs $10 more. If you go over by only 25 minutes, yer paying the difference between the plans....So why didn't you start off higher?? There's no penalty for switching down.

It's just kind of a "ya I know, but why?" question...Not trying to say anybody's stupid fer doing other things to help increase boost first....Just wondering why not do it the other way around?

Hooby

 

I have about a $3000-4000 budget. The evo V already has an intake and boost controller. What are my options? I definitely an aftermarket exhaust. I was looking at the apex-i N1. So far, I've been looking at upgrading my suspension first. what do you guys think of this set up. CUSCO everything. lower armbar type 2, 3 point rear bar, cf front strut bar, front and rear stabilizers, and the Apex N! damper system. I can get all this the exhaust and front pipe for about 3 grand. this is from japan at www.takakaira.com. are the prices on this site good? would you recommend not going for suspension first? please help. thanks!

 

Ralliart are the final word.... hehehe, that's really funny. What you call professionals, I call salespeople. Professionals are people that actually try and find the best value for money for you and know what they are talking about, there aren't very many, I admit. Have you ever thought that people might be selling you something that you don't really need?? Or do you go and buy everything you see on television too?
There isn't only one car out there that runs that sort of boost without internal mods, there is a LOT! F.e. I think that RC Developments don't put in the ARP bolts unless runnig over 1.6 bar or something. I would also like to see where you saw that JUN recommended what you said.... Anyway, you still have NO real example for your story, where as I have at least ONE and I KNOW of quite a few others. Go and have a look at some of the DSM sites to see what the 4G63 is capable of.

 

Mitsubishi and Ralliart designed and built the car! Suppose Mugen don't know Hondas. Suppose STi don't know Subarus.
Or they might just figure that you can't afford internal upgrades and tell you that you don't need them, just to get you to go for the more expensive upgrade. Alternatively, they may just give you a time bomb conversion so they've secured future business for themselves. They may be so ill-informed that they don't know and/or don't cover internal upgrades.
If I was running 1.4bar, I'd want my internals to be capable of 1.6bar. Call it engineering tolerance. Professionals know and understand this.

Well, again you're wrong there. The RC Developments Evo VI is in the December/January 2002 Issue of Banzai. In the spec. you'll see 'ARP rod bolt kit'. You'll also see that they used additional oil coolers to side-step the replacement conrod issue. This is also for an Evo VI with hollow crown pistons. We're talking about a V here. Not that there's evidence of their car having lasted very long yet anyway. Torque Developments International have never had an engine fail.
You have no real example of your story either. I could put 3bar through a standard engine but how long will it last. Tuning companys create cars for advertising purposes and can afford to spend endless hours maintaining them. This is very different from day-to-day use. What the hell does DSM mean?

On a lighter note, japspec4G63, I'd get the engine upgrading done before the suspension because it may need to be adjusted/reconfigured after a power hike. Might not make any difference but there's no disadvantage to doing it this way.

 

I was thinking about getting an Apex catback exhaust. who do you think makes the performing exhaust for the evo V or do you think it's all about the same? what about ecus? haltech? motech? custom? thanks!

 

The MoTeC M48 Pro piggyback ECU is good. I confess to not knowing much about haltech but 'Gems' is also worth checking out.