Finally Mapped

[Robsbc 0 1 Cars]

RobSBC, what have you done to achieve 1928cc (bigger pistons, what size?).

 

Omega forged pistons @ 83.5mm

 

Mos isn't running hydraulic tappets.

[mos 1]

Omega forged pistons @ 83.5mm

 

Mos isn't running hydraulic tappets.

 

Rob hate to correct you

but i am running hydraulic tappets

[maxi 36 1 Cars]

Matt advised the build, what with my engine making serious power and this one with the more aggressive solid lifter profile running on hydraulics it shows QEP can deliver the BHP. I think its all down to the clever lads at Catcams. Cannot express how impressed I am with these lumpy sticks!

 

Maxi

[Miles 331 1 Cars]

Nice result's, I'll have to dig my old ones out for my old 2l with couple of mod's mainly for the torque figure's

I'll get the system price to you on Monday and be intresting if you could get another readout done just for the info.

BMEP, Must say I'd never thought I;d see that talked about on here

[Robsbc 0 1 Cars]

No problem mark...

 

Just going by the Catcam catalogue :-

 

4901551

298 / 290°

252 / 244°

12.05 / 11.55mm

3.55 / 2.95mm

custom

MECH: rally & race

[Mattsav 1]

As long as the Rpm limits of the Hydraulics are observed then a mild solid profiles is Ok on hydraulics.

 

There are a couple of potential issues (Slight loss in low end torque due to the valve closing onto the seat slower) but Catcams have run tests on an engine dyno and found the losses to be so small that they can be ignored.

 

In real life tests thay have had no problems so thats the way we went!

 

I'll take that as a big compliment Dave

 

These big capacity engine are definatley the most cost effective method of getting sensible power.

More head flow is the way to go but this is much more expensive to the customer whereas the cams cost the same whatever the profile.

The slight loss in tractability wont be an issue in a light 205. It may even be a benefit as traction is certainly going ot be a problem.

 

More power is always available but its a case of getting the best package for the budget.

[jacobs53 0]

I did a research project in catcams performance camshaft for a TU 16v engine... something seemed very interesting that piper and kent cams couldn't achieve.

 

Anyway I won't bore you with the detail of the cams, but the only explanation I could find was that in order to fit there cam to the engine the cam axis offset had been modified to 0. Cleaver guys!!! As piper and Kent were recommending larger followers for the same camshaft grind.

 

This results in less rotation of the tappet when in operation but for a fully built race engine wear isn't such a issue with frequent rebuilds.

 

Must admit Catcams certainly have the technical brains in cams!

 

lee

[smckeown 1]

People stick with the alloy block because they (wrongly) worry that the extra weight of the iron block will affect handling.

 

Well that's your opinion and I disagree.

 

For a dedicated track car / race car the extra ~40kgs weight of the iron block mi over the 8v will effect handling/performance in my opinion.

[Sandy 189]

The actual difference is 17kg, but the distance from the yaw centre makes it significant. If you can't feel the difference, great, but if balance really bothers you that much, you'll be driving a 309 anyway

 

The TU blocks are 23kg different btw, more than the XU!

[smckeown 1]

sandy, your saying the iron block 2.0 is only 17kgs heavier than the ali 8v ? I understood there to be 15kgs diff between ali 8v and ali 16v; and 25kgs from ali 16v to iron 16v. Can you confirm ?

[j_turnell 134 3 Cars]

AFAIK theres around 20kg difference between the iron block and the ali 16v. Ali mi blocks and 8v should weigh around the same, deffinetly not a 15kg difference!

[jackherer 543]

I've driven similar spec 205s on track with alloy and cast engines and I cant tell the difference but then again I'm not a racing driver so maybe there is something I'm missing...

[VisaGTi16v 1]

Its not just the handling, making up for 20kg or whatever extra weight could be expensive in bhp/ton terms to get the same acceleration. Irrelevant on a track day but not when racing or sprinting etc

[Alastairh 47]

I think your mising the point.

 

Dave, maxi, matt etc are saying such good gains at low costs.

 

Remember everything comes at a cost. And i've driven both 1.9 and 2.0 mi's and i couldn't notice the difference, and thats the same opionion of many reputable people on here.

 

If your that bothered, go to the gym yourself and loose a few kgs!.

 

Alastair

[smckeown 1]

Yes i agree this route is the best for value for money for max bhp/per tonne. No question.

[VisaGTi16v 1]

I dont doubt that the 2 litre iron block is highly tuneable. I was talking about from a competition point of view, not going out and having a bit of fun. I won my class in a sprint this year by 0.09 seconds, if I had been 20kg heavier I wouldnt have. Thats how I see it. In an ideal world I would have 280bhp from a 1.9 or a 2 litre, which type is irrelevant as both would be so quick it wouldnt matter if one was a bit heavier

Edited January 31, 2007 by VisaGTi16v

[Sandy 189]

The Iron block is 17kg heavier than the Alloy block with liners etc. I didn't say anything about fully built 8v vs 16v etc.

 

Adding 17kg to the car isn't a big deal, but adding 17kg 120mm roughly ahead of the front axle line, does affect the balance of the car and turn in, in my opinion.

[smckeown 1]

The Iron block is 17kg heavier than the Alloy block with liners etc. I didn't say anything about fully built 8v vs 16v etc.

 

Adding 17kg to the car isn't a big deal, but adding 17kg 120mm roughly ahead of the front axle line, does affect the balance of the car and turn in, in my opinion.

 

But have you got any specific weights for the 8v vs 16v ?

 

I'd also assume as the iron block/head is taller centre of gravity increases

[Shevy 4]

Impressive results.

 

Any luck with the graphs yet ?

 

I'm also interested to see how quick the power tails off after 7400rpm

[Robsbc 0 1 Cars]

Impressive results.

 

Any luck with the graphs yet ?

 

I'm also interested to see how quick the power tails off after 7400rpm

 

Be nice to see the graphs too...

 

Is running cams for solid lifters on hydraulic lifters a bodge?

[Shevy 4]

The way I understood it Rob was that It's fine to do.The main limiting factor is the RPM at which the Hydraulics lifters don't work properly at. The main reason that it can be done is due to the capacity increase bringing down the RPM where peak power is, also I think you do need to run uprated springs but someone else will probably confirm that as I'm no Mechanic and don't claim to be an internet mechanic

Edited January 31, 2007 by Shevy

[Robsbc 0 1 Cars]

The way I understood it Rob was that It's fine to do.The main limiting factor is the RPM at which the Hydraulics lifters don't work properly at. The main reason that it can be done is due to the capacity increase bringing down the RPM where peak power is, also I think you do need to run uprated springs but someone else will probably confirm that as I'm no Mechanic and don't claim to be an internet mechanic

 

Thanks Shevy

[DrSarty 90 1 Cars]

If you're that bothered, go to the gym yourself and loose a few kgs!.

 

That's funny - but to do this he'd have to do enough aerobic work out to lose basically his torso and vital organs to achieve a weight loss of 20kg. Maybe a leg too; and I don't think anyone's that dedicated.

 

Plus if he used weights, as muscle weighs more than fat, then he'd accelerate even slower.

 

Whilst as I've admitted before that I clearly need phsyciatric help , the facts cannot be ignored that acceleration is directly effected by the power to weight ratio. Hence we're all arguing in circles coz if a heavier iron block can be more cheaply made to give large power gains, which are subsequently used up in shifting the extra weight, then this cancels out the logic in the iron versus alloy block argument.

 

If all we wanted to do is to compare power curve print outs from a rolling road session then surely that's against the whole driving spirit ethos of the 205?

 

What people are achieving here in power terms is amazing technically, but I learned a lot from Puma's story here (3rd post on page)and think we should all flag down a black cab and head back to what it's all about....driving enjoyment.

 

(Steps down from soap box)

 

Rich - expecting a nasty retort

[Sandy 189]

But have you got any specific weights for the 8v vs 16v ?

 

I'd also assume as the iron block/head is taller centre of gravity increases

The Mi16 is 13kg heavier than the XU9JA, but when I weighed the 1.8 16v back to back with the XU9JA, they were as good as the same.

[Batfink 201]

rule of thumb is for every 10kg you loose you gain 0.1 of a second 0-60 i think so more power offsets this quite easily