Boost level depends on which version you have I believe, i.e. the 150 or the 160.

Usual max boost on standard internals is 12psi.

I think standard boost is 12psi midrange and lower at the top end (7?) from what I've seen on my car (160)

 

Compression ratio is 9.2:1 I think the boost pressure is 8 psi but not 100% sure on that

 

Thats great, thanks guys! i will have the pistons rated for 15psi to give me some scope for more power as iam wanting roughly 200bhp, do you know what 12psi generates in relation to BHP? iam uprating pistons rods and liners, though keeping the standard crankwhich iam just hoping doesnt explode lol

 

I have read numerous threads etc on tuning the K Turbo and the consensus seems to be the crank is good for a max 300 bhp as the turbo will produce its power at lower revs than a n/a lump. I will be going down the same route with my Boys ZT in the future so keep us updated on pistons etc, I will be probably be using Maxspeeding rods as they do the shorter rods for the turbo.

 

will keep you updated, iam in talks with a company for k-series turbo rods, they make rods for subaru rally cars, so have a good reputation, will let you know how things go but at the moment they are looking alot cheaper than the max speeding ones

 

I have and am using the maxspeeding shorter rods and have Omega pistons which have been turned down slightly to reduce the cr as they are higher comp than standard and I wanted them running as standard. I also have the option to run a 1mm head shim if using standard Omega pistons unmachined in another engine mate

 

i have seen your thread ian and am very eagerly watching over it to see how things go

I decided to take a slightly different route for a few reasons:

1: cost - the pistons iam having done as a one off by a company based about 20 miles from my house and 3 miles from where i work is not only conveniant but also £680 for the pistons including rings, pins and locks is very competitive, i had tried contacting omega about these pistons, and they did not want to know

2: power - wheras you are going for a much higher bhp, iam only looking for about 250 max, as this is a car i will use every day i dont want some tyre shredding, fuel guzzling track car to commute with

3: knowledge - i am not a mechanically minded person, seeing your thread using the plastigauge and a chemists burette (giving me nightmares of a-level chemistry) basically scared the hell out of me, all the suppliers of my engine components are close by, so i can use their knowledge in helping me to build it back up, at worst i can stick the engine in the boot and drive the 20 miles to find someone who knows what they are doing, rather than e-mailing someone in america for help

will be interesting to see how well the 2 engines work, yours is more or less guaranteed to be a mind blowing sucess, but mine is to show (hopefully) that a more powerful turbo can be done on a budget by a numpty in his garage!

 

have you decided on what turbo you are going to use as I hav`nt really investigated that side of things yet

 

i have not ventured that far either, i have heard that nissan turbo's fit the standard manifolds, so possibly something like a pulsar or small skyline turbo would work well

 

Something else that may be of help is my Boy has messaged Z&R and they have confirmed that the mems 3 is fully mapable to over 300 bhp so no expensive after market management needed.

 

As far as I know there is no restriction on mapping the mems 3 other than the parts you are using. I do not know why people keep quoting 205bhp as the limit it will go to??? Maybe their (Z&F) limit running standard Rover parts but I just do not understand why people think it can not be mapped to any setting parts on your engine permitting. Am I missing something? Interesting to see your comment Paul as when I spoke to them 2 years ago they told me the same that whatever my build they could fully map it to suite.

 

Emerald Vs Mems

Having just spent 2 hrs reading through various articlea on the Emerald site it appears that in a lot of cases the Mems3 peak power readings are higher than those from the Emerald maps BUT throughout the rest of the range the Emerald produces better bhp and torque

 

At the end of the day it is the map/mapper that makes the difference. You may need to substitute a higher MAP sensor to go to higher boost levels but that should be straightforward. I would imagine a 2 bar sensor would top out at about 200bhp(ish).

 

That may well explain the figure of 205 bhp on a standard engine

 

Will be intetested to learn more about these pistons. That's a great price for one - off. Less than I paid for my wossner low comp pistons and that was part of a set of 4.

 

I made enquiries with Omega about this exact thing back in 2013 and did start a thread but at that time there was no interest.
Below is the reply. 3 sets 12 pistons need to be made to get the price basically a forged turbo spec piston running at the correct CR. I went ahead and modified my own hc Omegas and have the pattern ready to send to them for their approval or alternative design

Our minimum order quantity would be 12 pistons and our lead time at the moment is 8/9 weeks. As previously stated, these would be custom, so completely suited to your engine, so costs are difficult to estimate. If we can achieve the design from existing tooling with no 3D machining involved, you would be looking at around £115.00 GBP each + VAT including rings, pins and clips.
>
> If you think you might like to go for custom pistons, you can send in a sample piston and we will give you a definitive quotation. If you choose to not proceed and order, we will return your sample at no extra cost.

 

I use pistons from JDM dyno/UK in my supercharged K S1 Elise. They are designed for a 9:1 CR and std head volume.
They are manufactured by Wössner, but are a JDM dyno exclusive design and only available though Jon.
http://www.jdm-dyno.com/contacts.html

They are about 650 quid, but worth every penny. They are machined on both sides to save weight. I have matched the weight of all four pistons to below 0.05g.

They weight 222g without rings and pins. This is very light. The same Wössenr 12:1 CR pistons wights about 100g more.
He build a turbocharged Elise with 280HP. I spoke with the owner. The car is fast.

I use them with std length chinese steel rods, Mahle motorsport bearing shells and nodular iron liners from Westwood.
CR is further reduced by a 1mm copper shim. CR is about 8.3:1.
The shim is mainly there to save the cylinder head from indentation.
Head is a lightly ported VVC160 head with some chamber work, curtesy of Roger Fabry, a blanking kit and Newman ph2 cams.

Earlier this year I have also upgrade from a Rotrex C30-74 to a C30-94.
Boost went from 0.55bar at 7000 rpm to 0.8bar at 7000 rom and 0.85 bar at 7300 rpm, the rev limiter. Gearbox is a B4BP.
Never been on a dyno. The engine like methanol water injection and gains considerable HP. Not spring, I have to add a bigger pre rad for the charge cooler.

Here is a pull in 5th gear only, but no water injection, on the Autobahn to the limiter (about 143mph).
https://www.youtube.com/watch?v=EJt2Hb0gWZc

Marko