The next step. More power!

[Peter255]

Just back from Owens!

Headline fugure is now 257.6 BHP @ 6600rpm [smilie=icon_cheers.gif] (up from 248.2 @ 7100 prior to AWT manifold work).

Over book figure :wink: at lower revs and around the 260BHP I was hoping for.

Significant gains across the entire rev range too! Infact very nice gains in mid range torque (10+Lbft gain from 2500 - 6750). Biggest torque gain from 3000 - 5500. Which will be nice for the road!

Peak power ~500 rpm earlier than before and then it seems to drop back to the previous output levels from 7000 to the limiter. Maybe some other restriction? Need a plenum spacer Ben? [smilie=doubt.gif]

I'll post up the trace when i can be arsed to connect up my scanner...

Cheers
Peter

 

[TRW1]

Nice one!

 

[stevo]

cool cool, running well now

 

[Peter255]

Yeah well pleased, no where's my scanner....

Peter

 

[BenR]

Good news peter, told you not to worry :wink:

Peak power will be achieved earlier as the engine can produce higher levels of VE, cylinder filling, at lower rpm and produce a higher specific torque, rather than having to rely on rpm to process the same amount of air. The cap your hitting is most likely to be due to the engines total ability to process air, namely cylinder head/cams and inlet manifold design. A spacer might help a little bit and it might alter the torque curve as the pulse waves are reflected at different time intervals, so i cannot say for sure which way it will swing, but the larger volume should help either way.

You'll be able to continue the process of chasing the next restriction and increase your output levels, as I know that particular manifold is capable of 290bhp at least.

Get that graph scanned!

 

[Peter255]

Yes i'm too lazy to connect the scanner :badgrin:

Peter

 

[BenR]

Looks great!

Sort out some of that latter stage breathing and that line will just continue on up!

Torque curve is impressive though.

And all this on stock, mild as a korma, cams!

Mind you, the jeggedy torque curve post 5500rpm corresponds with the de-phasing of the vvt pulleys, so I have no idea on the effect if they were kept open, or are suffering other ill effects.

 

[Peter255]

Ben,
If I can keep it from dropping off in such a way between 6750 and 7250 there looks to be 260+ there to be had... Ideas?

Peter

 

[Jamesv6]

Reading this with interest and pleased for you Peter.

Is your right foot quite steady?

 

[Peter255]

Reading this with interest and pleased for you Peter.

Is your right foot quite steady?

For insurance reasons you are not allowed in the dyno cell. :wink:

Peter

 

[Duncan]

As i said the other day, its a great result! and congrats for being in the elite club of mk2s that make (and clear) book figures!

whats next? more? or is the quest complete?

 

[Peter255]

As i said the other day, its a great result! and congrats for being in the elite club of mk2s that make (and clear) book figures!

whats next? more? or is the quest complete?

I'm going to look into a plenum spacer (and anything else that i can come up with) to see if anything small can be done to improve the breathing at the top end as it appears to be running out of puff between 6750 and 7250. The std mk2's make their top figures just before the limiter so i want to see if i can get the same and thus look to get over 260. It looks on the cards i can sort out that apparent "restriction". But is may be something elsewhere entirely.

But we now have some firm quantitative info for other owners to think about WRT mods.
For a mk2 full decat (inc manifolds), modified mk2 plenum, induction kit, and bespoke ECU map looks to be ~260BHP and more torque across the rev range. All of which fits under the std covers.
Which may be the max simple bolt on mods you can do....

Peter

 

[Brett]

Nice work Pete :thumb I take it head works on the cards now? There's some nice cheap heads on Ebay at the moment to get started with :wink:

I hear Nissan 350Z owners are having brilliant succes with the spacer plates. Will be very suprised if you struggle to get an extra 3 bhp.

 

[Jamesv6]

Found the perfect spacer for you Peter.

:wink:

 

[Peter255]

Found the perfect spacer for you Peter.



:wink:

An expensive doorstop! I feel your pain!

Thats the point of this thread to try to work out what does / does not work (measured by independant people :wink: ).

Similar idea tho. Just badly executed!

Peter

 

[BenR]

Wow! Déjá Vu!
I swear I've thought of something like that before lol.

Peter, If you give me a little time (I'm in the middle of moving the workshop) then I'll be able to make a plenum spacer out of ally with twin O ring seals on both sides to negate the need for gaskets (a large cost saving for those who will forever be taking their plenums off). I wouldnt bother with 'ptfe' type spacers as these degrage over time and especially with heat, ironically, and deform over time. Add the fact that they are pratically pointless during high mass air movements as there isnt the time frame for air to conduct much heat.

Pricing will probably be a teeny bit higher than most expect simply because there is a huge amount of wastage generated from either milling or water jetting out of ally plate. About 80% of the plate will be wasted as offcut, and it'll have to be thick plate to be of much use.

Its also only a trial as the design differes greatly between something like the 350Z and the clio V6 and cannot be directly comparable.

You will get significantly more from headwork, but that also includes a significant price difference and can hardly be regarded as a bolt on.

And it might, for the sake of an easy check, be worthwhile holding the vvt phased until the redline to see if it does anything to the curve.

 

[Peter255]

Ben,
As already discussed i'm v interested. Drop me a mail / PM and we can discuss prices. It will be all fitted next year now anyway so no hurry for a bit to cover your move.
Tell me more about the VVT phasing tho. How could i change that?


Cheers
Peter

 

[Jamesv6]

I had drawn these ally spacers and thought they might be too difficult to machine/cnc so I scrapped the drawing.

 

[BenR]

Obviously you should have shredded them........or just not have been so trusting.

The vvt is meant to dephase again at 5500rpm, or 'retard' the cam timing. However, you could aftificially hold this open by applying a ground to the trigger wide of the vvt mech and checking how the power curve would run with the vvt phased through the entire rev range, then you could do the same with the vvt dephased. After you could overlay each curve and see which makes most power/torque in each region.....and if smart, program the vvt to phase or dephase in those particular areas. Although, i have no idea if phasing the vvt to the redline will see any gains at all.......but theoretically you might by reducing the LSA of the cam timing.

It all depends how far you want to go really, and how much effort you want to put into chasing the next 5bhp which might arise from the spacer/vvt checking. You might end up spending a few hundred quid installing spacers, checking vvt on a rolling road and remapping.

But on the other side of the card you have a large amount of money spent on cylinder head work and cams to see substantial gains.

Tuning, what a joy....... [smilie=icon_cry.gif]

 

[Peter255]

A little observation, having spent some more time driving her. Its all very subjective but the midrange does feel very good now. You can really feel it surge on as it gets into its stride. Before it was a bit strangled. It never really "WENT"! A sort of mild coming on boost sensation can now be felt. Now you can feel the acceleration build pleasantly as you go up the rev range. It reallt does stick you into the seats.

Well pleased. Thanks Ben and Mark! Oh and thanks for reading.

More next year (if i get my bonus! )

Peter ::