Input on power gains by swapping head.

[moelk]

Hi

Im in need of some feedback regarding cylinder heads.

I have a L28 engine bored 1mm with flattops, triple 45s, Schneider stage 3 cam, header etc...

CR is around 10.

The car puts down 180-185 hp to the wheels (tested on two different dynos).

It performs and drives really well and was built with help by a friend of mine 2-3 years ago.

The thing is I have the 260z E88 head, many times called a boat anchor on my engine. Head is shaved a lot so the chambers are now 44cc (messured 48cc from the beginning) and it has the same valves and seats as N42 head.

What do you guys think, would i gain enough power for it to be worth the money and hassle (I live in Sweden and we have no parts here) by let’s say using a P90 head instead?

Those of you who have swapped head on your engine what’s your experience?

 

 

//Andreas

 

 

[Zed Head]

35 minutes ago, moelk said:

The thing is I have the 260z E88 head, many times called a boat anchor on my engine. Head is shaved a lot so the chambers are now 44cc (messured 48cc from the beginning) and it has the same valves and seats as N42 head.

What do you guys think, would i gain enough power for it to be worth the money and hassle (I live in Sweden and we have no parts here) by let’s say using a P90 head instead?

 

Those of you who have swapped head on your engine what’s your experience?

I haven't swapped a head.  But, your E88 is probably not much different than an N42, if it has the same valve sizes. 

A P90 has a larger combustion chamber and will lower your CR.  And it has the same valve sizes.  So, basically, all you'll get is a lower compression ratio.  You will get some "quench" but, even though quench is supposed to be a good thing, it's not very clear that Nissan's quench really offers much.  People talk about the theory and the principle but the actual benefits are hard to measure.  

Plus, you have to get it just right or you end up creating a problem.  https://help.summitracing.com/app/answers/detail/a_id/4941/~/engine-basics-–-quench

 

[moelk]

I will make the CR 10ish with the P90 If i go that way. 

[madkaw]

How much timing can you run with that combo - total advance . 

Can you get good fuel there? You could bump compression with a better head and maybe timing too? 

That  p90 would have 53cc chamber unless you shave it. 

Try a different cam?

Is that e-88 ported .?

[moelk]

My e88 isent ported.

I run 17-18 degrees at idle and 35-36 at total now.

95 or 98 octane at the pumps here.

I would like to test a different cam but would not like to put it in this head if I can get a “much” better result together with another head.

[240260280]

Shave of 2mm off a P90 will put you ~9.9CR

 

 

Here is with E88 @44cc (~10.2CR):

Edited August 15, 2018 by 240260280

[moelk]

1 minute ago, 240260280 said:

Shave of 2mm off a P90 will put you ~9.88CR

 

 

Here is with E88 @44cc:

Yes I’ve used those, makes things easier.

 

[Jason240z]

11 hours ago, 240260280 said:

Shave of 2mm off a P90 will put you ~9.9CR

 

 

Here is with E88 @44cc (~10.2CR):

Which calculator is that?

[moelk]

http://atlanticz.ca/zclub/techtips/calcs/engine builder/index.html

[240260280]

This one is newer one: S30 Engine Modeller V3 Beta 3.zip.

Just unzip and run in any web browser.  If you look at the html code in a text editor you can easily see where the tables are and you can add your special configs.

 

btw Moelk, have you considered using 88mm VW pistons to increase displacement?  ?

 

- Crank: Stock L28 offset grind  (1mm extra stroke)

- Pistons: VW 88mm pistons shaved 1mm

- Rod: Stock L28 small end enlarged to 22mm for VW piston pin. Its working length needs to be shortened by 0.5mm so an offset bore on the small end or big end will do it, (or skim more off the piston top)

- HG: Stock

- Head: your current E88

- Rod bearings: -1mm to adapt to offset grind.

This configuration optimizes squish, mildly strokes, and increases displacement with mostly stock parts and some common machining work.

It will bump up your compression to 11.1

 

 

 

 

[moelk]

1 minute ago, 240260280 said:

This one is newer one: S30 Engine Modeller V3 Beta 3.zip.

Just unzip and run in any web browser.  If you look at the html code in a text editor you can easily see where the tables are and you can add your special configs.

 

btw Moelk, have you considered using 88mm VW pistons to increase displacement?  ?

 

- Crank: Stock L28 offset grind  (1mm extra stroke)

- Pistons: VW 88mm pistons shaved 1mm

- Rod: Stock L28 small end enlarged to 22mm for VW piston pin. Its working length needs to be shortened by 0.5mm so an offset bore on the small end or big end will do it, (or skim more off the piston top)

- HG: Stock

- Head: your current E88

- Rod bearings: -1mm to adapt to offset grind.

This configuration optimizes squish, mildly strokes, and increases displacement with mostly stock parts and some common machining work.

It will bump up your compression to 11.1

 

 

 

 

Engine only has 3000km since it was built so i won’t tear it apart and do it again ; )

Would be fun to test that combo.

Dony get me wrong, the engine is great and really goes well.

But i like to know why people call some heads bad and some the best heads when there’s no good documentary? At least I can’t find any.

When my engine was built the builder built another L28 engine at the same time. It was a F54/N42 combo with flattops, same cam, same carbs, a Mallory ignition (I have a zx ignition).

He has a canon intake, I have a Harada shokai.

My cars feels faster, both me and him feels this way. Guess it comes down to the intake?

[240260280]

I like the Maxima N47 head. It is one of the later heads and seems to have the same geometry as modified E31's for racing.  The exhaust ports are fine. Larger intake seats will help it.

 

btw it is nice to get a HP data point from your work!

185HP 10.2CR 2.82litre