Heads and FI

[ChilliWhizz]

Apologies for the thread title, doesn't give much of a clue... I've mulled this over for ages, and can't really answer my own question... which is... er, example... two identical engines, both with exactly the same specs, be it turbo or SC... so, using common 'stage' tuning terminology, taking these exact same engines, if you fit the same turbo or SC engine with stage 4 heads, will it produce more power than the engine with standard heads? My bonce says it will, because it will flow better, but if it's forced in, then shirly the advantage is only how quick the engine can exhaust it?

I'm probably being thick, but I guess the question is, is it worth expensive gas flowing of manifolds and heads if you can choose boost?

Wish I was clever fecker...

Chilli

[450Nick]

Give me a couple of days and I'll tell you..! Just had the engine rebuilt with ported& flowed heads, bigger inlet manifold and a new cam so will post up a dyno plot before and after if I can find the old one! Should be done by Friday...

[Classichim]

I think boost pressure over rides any gains porting, sort of a waste of money, more boost more power so as you say Chilli the limit must Sirley become the exhaust!
The thing is I'm thick so I'm probably wrong but that's my gut instinct.
Good thread.
You imagine that the better heads would increase power, so do it anyway but I get the feeling it's the boost that becomes your power sorce more than anything else!
I'd look at a flat plane crank mate, it won't drive on the road but you'd be a storm on track. 8500 revs,
No FI will get near you, it revs, you can drive it hard off turns and you'd set proper times!

Sorry I'm off on a tangent.

[NickOrangeTVR]

ChilliWhizz said:

Apologies for the thread title, doesn't give much of a clue... I've mulled this over for ages, and can't really answer my own question... which is... er, example... two identical engines, both with exactly the same specs, be it turbo or SC... so, using common 'stage' tuning terminology, taking these exact same engines, if you fit the same turbo or SC engine with stage 4 heads, will it produce more power than the engine with standard heads? My bonce says it will, because it will flow better, but if it's forced in, then shirly the advantage is only how quick the engine can exhaust it?

I'm probably being thick, but I guess the question is, is it worth expensive gas flowing of manifolds and heads if you can choose boost?

Wish I was clever fecker...

Chilli

Will make no difference - the whole point is that pressure overrides any need for porting.

[Hoofa]

And prob explains why Jools blended base works better than trumpets as it has a clear air path and it's getting rammed in !!


FFs chilli just flipping do it and stop procrastinating ,,, mind you last time you drove down the a1 I was sure you had some carpet stuck under the accelerator pedal so maybe you don't need it after all

[Discopotatoes]

NickOrangeTVR said:

ChilliWhizz said:

Apologies for the thread title, doesn't give much of a clue... I've mulled this over for ages, and can't really answer my own question... which is... er, example... two identical engines, both with exactly the same specs, be it turbo or SC... so, using common 'stage' tuning terminology, taking these exact same engines, if you fit the same turbo or SC engine with stage 4 heads, will it produce more power than the engine with standard heads? My bonce says it will, because it will flow better, but if it's forced in, then shirly the advantage is only how quick the engine can exhaust it?

I'm probably being thick, but I guess the question is, is it worth expensive gas flowing of manifolds and heads if you can choose boost?

Wish I was clever fecker...

Chilli

Will make no difference - the whole point is that pressure overrides any need for porting.

I disagree.
Any porting or head work helps the engine breath, so adding boost to a ported engine will increase performance,
The question should be is it worth the extra expense on better heads or would you be happy just upping the boost?
These engines don't like anything over 1.5 bar boost ( heads can lift) so there is a limit on turning up the boost.
Also the engine isn't in boost most of the time so all off boost activity will benifits from any normal tuning methods

[K4TRV]

NickOrangeTVR said:

Will make no difference - the whole point is that pressure overrides any need for porting.

Respectfully disagree.........the "effort" in creating the pressure when using a ported head will be much less to achieve the same volumetric efficiency of a standard head.

Less effort means less power lost in generating (u don't get something for nothing?) the greater output. Volumetric efficiency works with N/A or blown, so get a head that's ported IMVHO?

T

[SILICONEKID345HP]

Neal1980`s twin Turbo had problems trying to get more power ,it needed ported heads .

[Richard 858]

The thing is Chilli, you're probably talking about spending an extra £1200+ to get an additional 20-30 bhp. In my recent experience jumping from 275 to 415 was plenty in one step. The other consideration is how much can your gearbox, prop, diff & driveshafts cope with. All this power is useless if you can't put it down ! All IMHO of course.

[macdeb]

Discopotatoes said:

NickOrangeTVR said:

ChilliWhizz said:

Apologies for the thread title, doesn't give much of a clue... I've mulled this over for ages, and can't really answer my own question... which is... er, example... two identical engines, both with exactly the same specs, be it turbo or SC... so, using common 'stage' tuning terminology, taking these exact same engines, if you fit the same turbo or SC engine with stage 4 heads, will it produce more power than the engine with standard heads? My bonce says it will, because it will flow better, but if it's forced in, then shirly the advantage is only how quick the engine can exhaust it?

I'm probably being thick, but I guess the question is, is it worth expensive gas flowing of manifolds and heads if you can choose boost?

Wish I was clever fecker...

Chilli

Will make no difference - the whole point is that pressure overrides any need for porting.

I disagree.
Any porting or head work helps the engine breath, so adding boost to a ported engine will increase performance,
The question should be is it worth the extra expense on better heads or would you be happy just upping the boost?
These engines don't like anything over 1.5 bar boost ( heads can lift) so there is a limit on turning up the boost.
Also the engine isn't in boost most of the time so all off boost activity will benifits from any normal tuning methods

^^^ this. Porting and flowing will enhance FI. In not doing so you are limiting the possible power output and as Daz says, Neal1980 will explain his first hand experience I'm sure. Oh, and I was with him at the dyno. If you want around 400hp then boosting will be ok without head mods'. If you already have them [Chilli] then it's a bonus, yes?
Saying it makes no difference is er, how shall I say? erm not true.

Edited by macdeb on Monday 16th June 22:57

Edited by macdeb on Tuesday 17th June 16:26

Edited by macdeb on Tuesday 17th June 16:29

[SILICONEKID345HP]

ChilliWhizz said:

Apologies for the thread title, doesn't give much of a clue... I've mulled this over for ages, and can't really answer my own question... which is... er, example... two identical engines, both with exactly the same specs, be it turbo or SC... so, using common 'stage' tuning terminology, taking these exact same engines, if you fit the same turbo or SC engine with stage 4 heads, will it produce more power than the engine with standard heads? My bonce says it will, because it will flow better, but if it's forced in, then shirly the advantage is only how quick the engine can exhaust it?

I'm probably being thick, but I guess the question is, is it worth expensive gas flowing of manifolds and heads if you can choose boost?

Wish I was clever fecker...

Chilli

Looks like i might have something carbon under my bonnet

[phazed]

SILICONEKID345HP said:

Looks like i might have something carbon under my bonnet

I couldn't wait so bought a triple carbon plenum with a car attached

[macdeb]

SILICONEKID345HP said:

Looks like i might have something carbon under my bonnet

Daz, forget the carbon thing, get some de-comp' plates and turbo.

[OleVix]

On the stage 3-4 heads both exhaust and intake ports and valves are ported and bigger, so sure it will help to get the most out of the FI engine.

I contacted Paul Goodenough who makes the heads for V8d, he made me stage 3 heads, ported intake 45mm and shipping for 800... (without valve springs which I have)

Do the compression lowering plates work safely?

[Classichim]

Boom!
So how does the bottom end cope with all this power?
That's what keeps me away!!!
Is there a consensus as to how much the crank can handle let alone the drive shafts,
It's surely not just bolt on 450bhp and go,,,,, the gearbox and Dif are strong but you must be looking at a clutch and better drive shafts, etc.
enlighten me.
I'd suppose you could go for a completely different Dif and shafts, bespoke!

Could we put the gearbox used in LS conversions, ( mate it to the RV) and new prop.

It would be fab if we could get a Chimeara upto 202mph, Daz on to you mate, lol.
So you lads with bonkers power curves, who's going to do a flat out run in your FI examples and see just how fast the Dif will turn!!
Would we break 180mph?

That would get into Autosport, lol lol .

[Discopotatoes]

Classichim said:

Boom!
So how does the bottom end cope with all this power?
That's what keeps me away!!!
Is there a consensus as to how much the crank can handle let alone the drive shafts,
It's surely not just bolt on 450bhp and go,,,,, the gearbox and Dif are strong but you must be looking at a clutch and better drive shafts, etc.
enlighten me.
I'd suppose you could go for a completely different Dif and shafts, bespoke!

Could we put the gearbox used in LS conversions, ( mate it to the RV) and new prop.

It would be fab if we could get a Chimeara upto 202mph, Daz on to you mate, lol.
So you lads with bonkers power curves, who's going to do a flat out run in your FI examples and see just how fast the Dif will turn!!
Would we break 180mph?



That would get into Autosport, lol lol .

How many 4.6 rover v8 cranks have you heard of snapping ?

[Classichim]

There's your answer excellent, hang on a minute, but what RV8 packs 450bhp being forced in and ran for any length of time?
Is there any forced engines that have been running for a number of years and covered thousands of miles.
I'd love to see one if it has, mega.

[Alexdaredevils]

From what I've seen the bottom end of the rv8 looks pretty solid, (except the 500) as Richard said, how many cranks have you herd breaking?

[Classichim]

Can you improve oil flow to the crank bearings, that's my worry!

[SILICONEKID345HP]

Classichim said:

Boom!
So how does the bottom end cope with all this power?
That's what keeps me away!!!
Is there a consensus as to how much the crank can handle let alone the drive shafts,
It's surely not just bolt on 450bhp and go,,,,, the gearbox and Dif are strong but you must be looking at a clutch and better drive shafts, etc.
enlighten me.
I'd suppose you could go for a completely different Dif and shafts, bespoke!

Could we put the gearbox used in LS conversions, ( mate it to the RV) and new prop.

It would be fab if we could get a Chimeara upto 202mph, Daz on to you mate, lol.
So you lads with bonkers power curves, who's going to do a flat out run in your FI examples and see just how fast the Dif will turn!!
Would we break 180mph?

I think the same gearbox is in the Cerb ,it can handle the 4.5 AJP.

That would get into Autosport, lol lol .