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Discussion Starter · #1 ·
Please excuse any offence that the following may cause - it is not intentional, I merely wish to raise a topic for discussion.

I am interested in engine tuning options for the Evo VII. What puzzles me is that I see a number of posts relating to changing conrod bolts, induction systems, exhausts, ecus, solenoid grommet's , intercooler piping etc. however I have yet to see quantifiable evidence that these are a) necessary and b) make a measurable difference. I am not debating that they do not make a difference, I would just be interested in knowing, how much of a difference i.e. Dyno graphs before and after. To the best of my knowledge, none of the tuning companies publish this information on their web sites.

The first mod that I remain unconvinced about are the ARP conrod bolts. They should only fail when under excessive tension. The only time that this occurs is when the piston reaches TDC on the exhaust stroke and the load on the bolt is caused by the inertia of the conrod and piston still wanting to move up the bore and then dragging the piston and conrod back down the bore. This force is largely independent of anything other than the piston speed which relates to the speed of the engine. I believe that the standard engine is red-lined at 7000rpm and I would expect there to be a limiter at around 8000-8500? As long as you are not running the engine faster than the standard spec, why should the conrod bolts be more likely to fail whatever else you have done to the boost etc. Has anyone actually suffered conrod bolt failure?

On a turbo engine, it sounds entirely reasonable that changing the breathing characteristics of an engine will improve its performance. Using a less-restrictive intake/filter assembly will flow more air and thus generate more power. A less restrictive exhaust will increase flow and also generate more power. How much exactly is what I am getting at. It would be great if someone would dyno a standard car, change the air induction system, dyno it again on the same dyno and publish the difference. The same would apply to the exhaust. Has anyone done this so we can get some concrete figures relating to what these changes will quantifiably produce? I do not mean just peak numbers but actual power and torque curves so that the gain/loss is clear.

Ralliart Japan produces a Sport E/G ECU (RA560649R1) for the 7 that I believe Ralliart UK uses in the Extreme . They (Ralliart Japan) claim that this is to be used with their aluminium piping set, air filter and aftermarket exhaust. I would be really interested in seeing a dyno graph of the output of this combination as if this is true, it would provide a matched system that should be pretty good all for about GBP1500 |PLS| labour. Could anyone tell me if they have tried this setup?

The other issue that bothers me relates to induction piping kits and intercoolers. I have seen a number of kits available at prices approaching GBP1000 but absolutely no numbers to justify their superiority over the stock items or each other. The only reasons that I can see for changing the standard induction piping would be either the standard stuff cannot handle increased boost pressures and pipes blow off or the new kit is less restrictive to airflow and hence has a lower pressure drop across it. Unfortunately I have not seen any numbers provided with the kits comparing them to the stock piping to justify them. It would not be particuarly difficult to product numbers, two pressure gauges should be all that's needed.... The same applies to intercoolers, a better intercooler should ideally be more efficient (reduce temperature of the air to a greater degree than stock at max flow rates) and ideally provide less restrictive flow. Again, should not be too difficult to put numbers to. What I cannot understand is why the people who sell them do not provide us with proof of their benefit. It would be quite easy for them to do and better, they would probably sell more of a product proven to be better than stock. The thing that really bothers me is that they either have not thought of doing this or they have and the products do not provide a benefit justifying the price.

Sorry if this sounds a bit contentious but tuning any car is an expensive business and I think we all want to be as sure as possible that our cash is well spent. I would not have thought that anyone would argue with wanting to know the relative merits of modifications with numbers to back them up.

Phew, hard work this posting lark!
 
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Discussion Starter · #2 ·
silverxkr,

You make some good points in your posting. I agree that the tuning industry does not rely on enough hard evidence of improvements and you are left with the uncomfortable conclusion that it is because in many cases this is because there aren't any.

Whilst you will be able to search through the old postings on this forum to see where people have done before/after rolling road tests (certainly on Magnex exhausts) this is likely to be for the E6. As yet the E7 is still pretty new in the UK and beyond Ralliart and warrander I'm not sure that many tuners have had a go at it. The best bet may be to check the Japanese tuners.

E6 results should give you a good idea of what works and what doesn't, but with exhausts for example, this may not do you much good with an E7.
 
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Discussion Starter · #3 ·
Silverxkr,

There has been plenty of debate before on whether the ARP bolts need replacing and I too am unconvinced that this modification is required. However, I did get a quote for this work recently and at £240 it might be better to be safer rather than sorry.

I also agree it would be very useful if someone did carry out a true back to back test of a car with and without basic intake, exhaust and intercooler mods and publish some decent figures. I'm surprised none of the tuning companies out there have done that (perhaps there's a good reason why). Although I recently had my car (E6) power tested with just a Blitz filter and de-cat pipe and recorded 292bhp, but torque was down due to losing the peak torque 'bump' you normally see on standard Evo's.

Dave
 
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Discussion Starter · #4 ·
Ok. There are lots of problems here.

Tuning is not a simple business, so publishing a list of what results to get is probably impossible. Every dyno will give different results, and every tuner will bend those to make theirs look better!

In order to successfully tune a engine, you must look at the engine as a whole. For example, quoting 5 bhp increase from an air filter and 15 bhp from exhaust does not necessarily mean you get 20 bhp by fitting them both. Certain combinations of parts actually reduce the performance. The only way you can possibly get an accurate idea is to try every single combination of everything, on the same car, with the same air temperature, same petrol on the same dyno - which of course is not practical. It can't even be mathematically established. No two engines are the same. Castings vary, and power outputs vary. I see you have an XKR (more on that later). These vary from 350 to 390bhp stock. The same is true of EVOs. One owner will put an exhaust and filter on, and achieve 340bhp. Another will get 315bhp. Same parts.

The only thing you can do is make an assessment as to which parts of the engine are less than optimal, which is what a good tuner will do. Exhaust restrictions, intake temperature, volume of intake air, boost pressure and so on - these are all valid ways to increase power. The trick is to do so in a safe manner, which is really what we are looking to tuners to work out - what combination gives a good increase in power REALIABLY.

Really, the only way you can get the information you want is at an MLR rolling road day - you can guarantee that there will be enough EVOS with various different part combinations to estimate what works well and what doesn't.

The comments about the different air intakes, intercoolers etc. - these really aren't meant to give extra power. The whole point of cold air boxes, cold air lagging, bigger intercoolers, water injections etc. is to keep air temperature cool, regardless of ambient conditions, thus ensuring you get the same boost/power. This also helps prevent detonation too. The reason why they quote power gains is that colder air is denser and thus provides a bigger charge, so a bit more power. The real benefit though is to ensure that you get roughly the same density of air at all times. Normal engines will have temperatures varying wildly, meaning that power varies too. Ever notice how a forced induction car is faster on a cold morning than a warm day (sometimes considerably so)??

As for the XKR - my old XKR was used as the development car to raise power to 450bhp. This was done in the end with a bigger intercooler, blitz air filter, different supercharger wheel for more boost, big exhaust and so on. This was interesting, and relevant, as no one had tuned one of these before - and required us trying lots of different parts and techniques until we found a combination that worked well. For example, changing the exhaust cat back gave us 20bhp more. Putting racing cats gave another 15. Putting a small blitz filter gave us another 15. Blitz filter on its own, only 5. Bigger blitz filter on its own gave us 10. Big Blitz filter with exhaust, no difference to the small filter... and so on. Spent several weeks trying all the combinations on the car, and finally achieved 450bhp and 440lb/ft. Some of the electronic aids (VSAM from Racelogic) didn't work at all, or even reduced power. Great torque losses with certain exhausts.

My advice would be simply this : Think of how much power you want to achieve, and how you want that power delivered (peak power, good torque spread etc.) Then ask people who have done it how they did it, and to tuners too - and make your own choices.

There are enough postings on this forum to tell what things have worked well for other people.

Good luck.
 
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Discussion Starter · #5 ·
Blade

Sure putting on an exhaust, filter or whatever isn't going to release the full potential of a high performance part and you are really only going to see the benefit when you really start to push things and go beyond what the restrictions of the standard parts. And if you're looking at a serious upgrade overall you need to look at the bigger picture. But for people who want to just add a filter or exhaust it would be good to quantify exactly what that will give them. Don't forget thats what most people do and then leave it at that.

Dave
 
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Discussion Starter · #6 ·
There does seem to be a lot of debate as to what is good and bad. This is particularly confusing for newcomers which is why I bought an Extreme - I deidn't need to know. The power figures talk for themselves.

I agree with Blade on many points and am amazed that 2 tuners doing similar things get different power outputs. For instance, Ralliart get 340 bhp and 350 ft/lbs tourque. Warrander get 340bhp and 310 ft/lbs tourque, although I admit at a cheaper price. PE seem to have got some impresive figures out of Blade's car but even more expensive. I guess that the point that I am trying to make is it is more than the sum of the parts. It is how you combine them and what else you do. I am not sure that the best tuners really tell all their secrets. I am sure that Ralliart doesn't
 
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Discussion Starter · #7 ·
DaveG,

You certainly have a point regarding the cost of the ARP conrod bolts not being ridiculous. GBP240 is not excessive in itself but there is the hassle of taking the car in to get it done and leaving it overnight... My question was, is it necessary in the first place? Everyone appears to be doing it - perhaps it is entirely justified. Please do not think that I am categorically stating that it is not. I am merely sceptical as to the best of my knowledge and research, no one has had a bolt go on them. If I do not have them done, perhaps I will be the first....
 
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Discussion Starter · #8 ·
Blade,

I appreciate your comments. I fully agree that it is unrealistic to expect tuners to product dyno maps of every conceivable intake/exhaust/piping/intercooler combination. Off the top of my head, on the inlet side, I can come up with offerings from Ralliart (filter element), Blitz, HKS and A'PEXi. I am sure that there are others that I am not aware of. On the exhaust side there are at least an equal number of products. I am of the opinion that most of the combinations of these components, fitted to a standard engine, will probably not produce significantly different results. If they did, why do many of the members of this forum equiped with either the standard ECU or the Ralliart ECU use combinations of intake and exhaust and not one ideal solution?

I have followed the development of your car with interest, it is certainly a unique vehicule which promises to be a showcase of what is possible. Please do not take offense but I would estimate that you have plowed many, many thousands of pounds (I would guess approaching 20k) into it. Your experience with the XKR also seems to indicate that you followed a similar route tuning it. Unlike you, I am not interested in pushing the tuning of my cars to that sort of limit, I am looking for relatively minor modifications that will achieve the most bang for the buck! The compressor maps for the standard Evo turbos show that the best you can get in any case is maybe 370-380bhp. The turbo just cannot flow any more air than that which is required to burn the fuel. You may get a little more with a more efficient intercooler giving you a denser charge. I am interested in shooting for perhaps 350bhp. This is 25% more than stock. Your point regarding the variation in standard engine horsepower is well made and I am assuming 280 to start with.

Whatever one does to the engine however, assuming an unchanged compression ratio, optimised injection and ignition, free-flowing exhausts, the same charge temperature in the inlet manifold; at the same (true) boost all evo engines will give more or less the same power output. This is governed by physics. The one caveat is that apparently, the standard ECU calculates the boost that the engine is seeing from the volume of air that flows through the sensor. Piping and intercooler modificatons will change the effective charge. This would have to be corrected for in the above example either by mapping the ECU or using external black boxes.

I think it likely that the standard engine internals are stronger than most people give them credit. Group N cars are not allowed to change them under FIA rules and Mitsubishi are not going to produce a marginal engine for what is, the basis for a competition car. I would hazard that most problems occur because people make modifications to the engine without properly re-mapping the fuel and ignition curves as required. This is why a balanced solution such as the Ralliart combination that I mentioned in my original post is of interest to me. I do not see why it should not produce 340bhp or so with good torque if it is properly balanced. What I would like to see however are torque curves for these engines as strong mid-range is probably of more benefit than outright power. The Group N engines have extremely strong torque outputs from 3000 RPM upwards.

With regard to the induction and intercooler piping as well as the intercooler itself. The numbers I am interested in are applicable to all applications. They are not bhp figures but the pressure loss across components as compared to the standard ones can tell you that by changing, say, the intercooler, you will gain .2bar of boot that is being lost in the standard item. The temperature differential will also tell you how much denser the charge is likely to be and this can also be applied to your particular set up to calculate what the likely gain would be and more importantly, how much this gain is going to cost you.
 
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Discussion Starter · #9 ·
A few points:

Probably the first mod you should do is to fit a progammable ECU with data logging. Why? because if you data log you can measure vital statistics such as boost pressure, rpm, timing,detonation and lambda every quarter of a second. Typical tuning method is to roll from below 2000rpm in 4th gear all the way up to about 7500 with foot flat. This way you can base line the performance. For instance how long it takes to go from 2000 to 3000 can show the effect of changes in spoolup time. You should use a straight on a stretch of road you travel regularly and will find that results are surprisingly repeatable (generally within .25 of a second to 100mph |PLS|) and you can see gains and losses in the various increments. For instance a change to a big bore exhaust from turbo back might make the lower rpm increments take longer and the higher rpm increments take less time.

Also once a mod is done you can experiment with fuel, timing changes to optimise that mod. And you can compare this to what was possible pre mod.

As far as grp N goes be careful here. The presence of a restrictor alters the turbo characteristics to allow more boost to be developed lower down the rpm range (1.6 or morebars at 3000rpm). However boost has to be removed higher up the rpm range falling rapidly from around 4000 onwards. These motors make less power than a standard motor and there is no point doing big revs. The earlier motors (VR4) actually used heavier rods with larger bolts but these were overengineered for the grp N characteristics and thus they were lightened to improve response.

andrew
 

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Re: Re:Tuning the Evo VII

silverxkr said:
2 WELL ESTALBISHED TUNERS/ENGINE BUILDERS TOLD ME THAT ITS HYPE AND THAT THE CONRODS WILL GO FIRST.I RANG 4 COMPANIES ON ADVICE ON THIS MATTER.INFACT ONE OF THE COMPANIES HAS ONLY EVER SEEN THE CONROD BOLTS FAIL WHEN THEY HAVE BEEN CHANGED !!

DaveG,

You certainly have a point regarding the cost of the ARP conrod bolts not being ridiculous. GBP240 is not excessive in itself but there is the hassle of taking the car in to get it done and leaving it overnight... My question was, is it necessary in the first place? Everyone appears to be doing it - perhaps it is entirely justified. Please do not think that I am categorically stating that it is not. I am merely sceptical as to the best of my knowledge and research, no one has had a bolt go on them. If I do not have them done, perhaps I will be the first....
 
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