De cat pipe, power gains ?
De cat pipe, power gains ?
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ClassiChimi

Original Poster:

12,424 posts

178 months

Friday 19th February 2016
quotequote all
As tittle suggests, I'm just wondering what a nice Clive Y or similar would offer me in power gains,
If my engine had say a reputed 300 Bhp and 350 ft lbs torque using the Mbe Ecu and CATTED Y piece
What extra would a fully de CATTED system offer me on both the power and more importantly torque curve,
I'm using lambda's so that will have to be addressed I know but re mapped what should I expect. Ball park will do,, I'd like to see 325 Bhp for instance but not sure if that's feasible ?
Cheers Alun

4.6 engine !

OleVix

1,438 posts

177 months

Friday 19th February 2016
quotequote all
ClassiChimi said:
As tittle suggests, I'm just wondering what a nice Clive Y or similar would offer me in power gains,
If my engine had say a reputed 300 Bhp and 350 ft lbs torque using the Mbe Ecu and CATTED Y piece
What extra would a fully de CATTED system offer me on both the power and more importantly torque curve,
I'm using lambda's so that will have to be addressed I know but re mapped what should I expect. Ball park will do,, I'd like to see 325 Bhp for instance but not sure if that's feasible ?
Cheers Alun
You could expect 10-20 horses, some have had more gains, esp on 5l engines

ClassiChimi

Original Poster:

12,424 posts

178 months

Friday 19th February 2016
quotequote all
I probably need bigger injectors too, then the fuel figures plummet, about 20 hp is what I thought, mmm would I get a similar torque figure increase or less as I'm imagining, ?

Pupp

12,948 posts

301 months

Friday 19th February 2016
quotequote all
Not sure why you think running sensors is an issue; before I went Emerald, I used an Adams chip in closed loop with an ACT Y and little cats out, ran real good

QBee

22,464 posts

173 months

Saturday 20th February 2016
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Mine has the decatted Y and lambdas. Works fine.

phazed

22,464 posts

233 months

Saturday 20th February 2016
quotequote all
My decatted 4.6 running the usual 72mm plenum, Typhoon cam and V8D stage 4 heads.


QBee

22,464 posts

173 months

Saturday 20th February 2016
quotequote all
After three years of watching these power threads, I am convinced that the words "stage 4heads" are the only really significant thing you need to read on that last post.

When Phazed bought his 5.5, it had stage 3 heads and underwhelmed him somewhat. He still at that point had the 4.6 with stage 4 heads. After a discussion on here he was persuaded to go into his multi garage establishment at Phazed Towers, and swap the heads between cars. After doing that, the 5.5 on stage 4 heads was considerably more powerful, around 380-390 BHP IIRC.

I conclude that we can upgrade our plenums, injectors, hoses, AFMs etc all we like, but unless we fit bigger valved heads, our BHP output will always be less than we expected or hoped for. My own V8 D 5 litre, with all the extras, but stage 3 heads, is a case in point - a mere 315 BHP.

Bassfiend229hp

5,530 posts

279 months

Saturday 20th February 2016
quotequote all
QBee said:
After three years of watching these power threads, I am convinced that the words "stage 4heads" are the only really significant thing you need to read on that last post.

When Phazed bought his 5.5, it had stage 3 heads and underwhelmed him somewhat. He still at that point had the 4.6 with stage 4 heads. After a discussion on here he was persuaded to go into his multi garage establishment at Phazed Towers, and swap the heads between cars. After doing that, the 5.5 on stage 4 heads was considerably more powerful, around 380-390 BHP IIRC.

I conclude that we can upgrade our plenums, injectors, hoses, AFMs etc all we like, but unless we fit bigger valved heads, our BHP output will always be less than we expected or hoped for. My own V8 D 5 litre, with all the extras, but stage 3 heads, is a case in point - a mere 315 BHP.
  • chuckle* ... Is that their Stage IV "Mk1" or Stage IV "Mk2" spec though. biggrin

ClassiChimi

Original Poster:

12,424 posts

178 months

Saturday 20th February 2016
quotequote all
Bassfiend229hp said:
QBee said:
After three years of watching these power threads, I am convinced that the words "stage 4heads" are the only really significant thing you need to read on that last post.

When Phazed bought his 5.5, it had stage 3 heads and underwhelmed him somewhat. He still at that point had the 4.6 with stage 4 heads. After a discussion on here he was persuaded to go into his multi garage establishment at Phazed Towers, and swap the heads between cars. After doing that, the 5.5 on stage 4 heads was considerably more powerful, around 380-390 BHP IIRC.

I conclude that we can upgrade our plenums, injectors, hoses, AFMs etc all we like, but unless we fit bigger valved heads, our BHP output will always be less than we expected or hoped for. My own V8 D 5 litre, with all the extras, but stage 3 heads, is a case in point - a mere 315 BHP.
  • chuckle* ... Is that their Stage IV "Mk1" or Stage IV "Mk2" spec though. biggrin
Well yes, stage 4 what, is that matched to the inlet, it's got more CC's in the engine to so more suck,, but it does seem clear, your heads the thing that matters,, going by Peters old 4.6 I should be around 325 Bhp de CATTED but I'd be surprised if it was as I have standard Plenom etc,, today at Bedford my car sounded loud to me,, I'd fail the noise text so then I need cans etc,
I'll leave it alone for now.

QBee

22,464 posts

173 months

Saturday 20th February 2016
quotequote all
It's the valve sizes that restrict the amount of fuel/air mixture getting into the engine, I think, Alun, and that determines the power output.
Your 4.6 valves will be smaller than Peter's stage 4 head valves. Look, I could be wrong, but I don't believe the other components, such as plenum, AFM injectors etc make much difference if the valve sizes are the restricting factors. Jools said as much to me when he checked over my car in November.

So, if I want another 30 bhp I need a pair of stage 4 heads. Which fitted will set me back around 2 grand. That's a long way towards supercharging the thing and getting another 80-100 bhp. Your money, your man maths.

What do other people think? The informed ones, I mean.

Bassfiend229hp

5,530 posts

279 months

Saturday 20th February 2016
quotequote all
QBee said:
It's the valve sizes that restrict the amount of fuel/air mixture getting into the engine, I think, Alun, and that determines the power output.
Your 4.6 valves will be smaller than Peter's stage 4 head valves. Look, I could be wrong, but I don't believe the other components, such as plenum, AFM injectors etc make much difference if the valve sizes are the restricting factors. Jools said as much to me when he checked over my car in November.

So, if I want another 30 bhp I need a pair of stage 4 heads. Which fitted will set me back around 2 grand. That's a long way towards supercharging the thing and getting another 80-100 bhp. Your money, your man maths.

What do other people think? The informed ones, I mean.
As an uninformed arse (as opposed to a uniformed arse) I'm surprised at the brick wall that seems to be the valve limitations but I don't have any reason why I should be surprised - after all they will flow a finite amount at atmospheric pressure and that's your lot.

I've gone for the biggest vales on standard seats (V8D Stage 4 Mk1) rather than the bigger seats for pretty much teh same reasons as you put there ... the plan is to get the lump well run in and then supercharge it.

Phil

ClassiChimi

Original Poster:

12,424 posts

178 months

Saturday 20th February 2016
quotequote all
Some say if your super charging why waste time with the porting or valve sizes as it far out ways the gains anyway, Richards super charged car today seemed way way fast. You can't beat it really this FI lark.

Bassfiend229hp

5,530 posts

279 months

Saturday 20th February 2016
quotequote all
ClassiChimi said:
Some say if your super charging why waste time with the porting or valve sizes as it far out ways the gains anyway, Richards super charged car today seemed way way fast. You can't beat it really this FI lark.
Because I'm not going FI straight away - and it's *POSSIBLE* that I might be happy with what I have for a year or two.

It seemed like a sensible use of funds to replace the heads (as they needed completely refurbing) with the biggest sized valves that I could without spending silly money - that way I could make the most of what I have (which I'm really hoping will be north of 300hp and I've been told "should" be 320hp/350ftlbs but who knows) and still have something that doesn't have too much wasted work *IF* I decide to get it supercharged.

Phil