View Full Version : Pistons and con rods

24-02-2001, 20:22
What are the best pistons/con rods/gasket for the evo6 tme? for high boost and power.

Dennis the Menace
25-02-2001, 10:16
My opinion is that if your power is below 330 hp or there about, I would consider changing to GRP-A head bolts and ARP conrod bolts.I would only start to consider about upgrading the pistons and conrods when you are taking it up to 350|PLS|hp. Try contacting Dragonautosport/sales@dragonautosport.co.uk, they have a vast range of upgrading items like pistons, crankshaft, conrods and so forth.

25-02-2001, 16:53
Evolution, Dennis is right,if you have less than 340bhp,and you don't want to go for high power upgrades the best solution is to change the bolts,and why not the head gasket.

Anyway the most common high quality parts to go for are the hks. You can find them in uk.
They have forged pistons,conrods,upgraded head gasket and everything else.
You can find them at www.tdi-plc.com

BOZZ SPEED have some forged pistons too and they use hks conrods for their 500bhp evo.
You can see some pictures at http://communities.msn.com/EvolutionV or www.bozz.co.jp

JUN have a full engine kit for the evo vi(2.2L)composed by a special crankshaft,pistons and conrods. You can see pictures and prices at www.junauto.co.jp

25-02-2001, 19:43
Thank you very much for the info !
I am considering the up rated engine internals as I expect my car to produce around 400 hp. The big end bolts I already did, and much more, you can see in www.evoblast.com.
I donít like HKS so much, I have installed several items from them on my car, a larger intercooler, oil cooler and turbo pipes. The turbo pipes were really difficult to fit (my car is a LHD and there was a problem with fitting in the area of the master brake cylinder).
What about Carolli con rods?

Dennis the Menace
26-02-2001, 10:10
I do share your opinion, I do not care much about HKS products either. I am not saying that all HKS products are bad. Put it this way, they are not good in everything they made. Heard from somebody that the HKS intercooler is not a huge improvement over the std. intercooler. Considering the amount of money you have to spend on a HKS intercooler. Now that your car is producing more than 350hp, is time to look at some aftermarket engine internals. Is going to be rather expensive to do a rebuilt if the engine goes. There is no prior warning as to when it goes.

26-02-2001, 11:27

I think that if you want to go for a really good upgrade,you should go for the JUN kit.
It's expensive but it's really good quality,they made 1000bhp upgrades for nissan skylines and their kit includes a shaved cranckshaft to bring your engine at 2,2liters.
They have also camshafts and pulleys,valve springs,valve retainers.

Did you had a look at their website?

Bozz speed pistons seems to be a good option if you don't want to go for the JUN kit,
and if you don't want HKS conrods, POWERENGINEERING supply uprated ones.

I don't know if you can order parts directly from JUN,you can email them,otherwise up auto is maybe able to order them.

www.powerengineering.co.uk www.upauto.co.uk

Hope this helps

26-02-2001, 13:29
Well if you plan building up a 400|PLS||PLS| HP engine, hell yeah its best to upgrade everything then already for maximum reliability! [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1-->

Bozz Speed forged pistons are very very good, arguably the best ones on the market, and I'd say comparable to the RS450 engine conversion package. Jun stroker kit is good, but it won't be advisable to crank up the boost on a stroker kit because of the longer stroke and its pistons aren't as low-comp as one would like them to be for high boost applications (Bozz Speed has 8.0:1 compression ratio pistons, ideal for boosting really high, like 26-28 psi and up)

You can email / inquire about the Bozz Speed kit from their master mechanic who speaks english, Yuki Hisada at crazybear@dream.com for more details. He cane build you an engine too if you want, but labor for him alone would cost you a Thousand US Dollars a day! [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1-->

Good luck! [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1-->

13-03-2001, 17:32
I have had the Omega pistons and Arrows Con rods fitted into my engine. Very pleased with the new engine except for one point. OIL CONSUMPTION.
Becasue the tollerances ofthe GP-A stuff is slightly 'looser' I am getting throug no end of oil. I am using approx 1 Litre per 250 miles. I believe that this is standard on engines of this spec (at least it seems to be the case with other RS450 engine owners that I speak to). Its not really a major problem, as I dont seem to be burning it as such, it is just bloody expensive !!

13-03-2001, 23:07
Mark is this natural?

I think there is some thing wrong if you are using a litre per 250 miles.
What's it being used as octane boost?Even if the turbo is burning a little of it ,No way should any engine use this much oil over such a short space mileage.Sure your piston rings are ok?No slight decrease in compresion over a space of time.


Paul s

14-03-2001, 11:42
Omega pistons in Evo engines have a reputation for high oil consumption , not good , the oil pollutes the fuel/air charge and effectively reduces resistance to detonation.

Mr Mime
20-03-2001, 11:04
If you go to using forged pistons over cast pistons you have to expect an increase in oil
consumption, since the tolerances at cold for the forged option have to be set higher,
because forged pistons although much tougher than cast ( reduced porosity ), do expand more.
When the engine is at operating temperature the oil consumption is reduced, it is
the warm up period when most oil is lost/burnt off.

-Mr Mime

03-04-2001, 02:16
According to the Technical manual for the E4,5|PLS|6, The pistons are forged as standard.

The E3 pistons weren't.

The piston skirt was reduced in size on the E5 piston to reduce weight and the oil gallery was added on E6 pistons but all are forged.


03-04-2001, 03:11
Hi there....I would go for the Jun items too. They are top quality, and have a good reputation in Japan. Worth giving a call to OS Giken. They specialize in full engine conversions and make one of the best for the GTR. Not sure if they make anything for the Evos but if they do you should consider them. HKS are a bit too comercial...they are well know only because they are big..like Blitz and so on. Try looking for more quality goods from lesser known specialists....Japan is full of them. For example ...intercoolers. Dont go for HKS, try out ARC. They make great ones and even construct bespoke ones to any specifications. They even use titanium to make them!! They are pricey, but what do you expect.
Oil consumption....shouldn't you go for a oil-sump upgrade after such mods!?? If you are using different turbo or higher boost you should protect your engine with a bigger sum/pump...no?!?!?

Braf (ptb)
20-04-2001, 03:21
Has anyone come across a titanium conrod from Japan called Tomai?

Braf (ptb)
19-05-2001, 02:51
Someone must have heard of these rods?

A Guy in Jamaica has ďTomaiĒ? rods fitted to his engine. He reports huge gains in engine acceleration. Apparently they are almost indestructible. He fitted them after bending one of his stock rods.

Anyone in Japan know of these?

19-05-2001, 08:36
Interesting He reports huge gains in engine acceleration it's a shame none of these cars can ever be seen performing, only claims on various websites etc.. The EVO hardly revs slowly when standard let alone after the usual mods that we all do, I have never noticed a huge increase in engine acceleration after fitting uprated rods in any of the modified cars that I have been involved with. It takes a lot more than rods alone to make substantial changes in engine pickup/acceleration.

Kevin A

Braf (ptb)
19-05-2001, 11:30
There are many good things about living on a small rock. Unfortunately however, economic constraints make it unlikely that you will find a rolling road down around the corner. [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1-->

I did get this information third hand and so canít even offer my personal impressions of this mod I know next to nothing about. On the other hand I find it entirely plausible that gains can be had from fitting titanium rods. I may stand correction here but didnít Mitsubishi drop the piston mass in revising the E4 to E5? I am guessing that lowering the mass of engine internals will let the engine accelerate faster. The reciprocating mass of the piston and rod must figure in the equation.

Anyway I am not advocating their use. I just want to know where I can find a set!

19-05-2001, 15:21
Where did you get that info. from? Whose car was it?

19-05-2001, 15:41

I contacted the Bozz guy over a month ago, no reply!

Braf (ptb)
19-05-2001, 16:49

Peter told me of the guy. Peter knows him from rallying. I will ask for a name and let you know.

The story goes that when you put intake advance into these engines and are running high boost the rods will eventually bend. Peter was surprised as he was mixing toluene and had no sign of detonation. Reported huge top end power!

Your countryman had a similar experience and fitted these rods and has never looked back.

If anyone thinks that this is pure fantasy, please feel free to ignore it. [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1--> If you know where to find the rods, do tell!

Braf (ptb)
30-05-2001, 07:25

I think I have found these guys. Anyone do Japanese?[img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle ><!--e1--> Have a look and see if these are the right ones.

<a href|EQU| http://www.tomei-p.co.jp/webcatalog/conrod2.html target|EQU| _blank ><!--auto-->http://www.tomei-p.co.jp/webcatalog/conrod2.html</a><!--auto-->