Alfa Romeo Forum banner

1 - 20 of 51 Posts

·
Registered
Joined
·
10,929 Posts
Discussion Starter #1
I want to build an 11.5:1 compression, 8000rpm Busso :devious:

It must look stock (No ITB's but larger throttle, plenum and MAF is planned)
It must be N/A (no turbo, no supercharger)
It must be as reliable as a daily runner
Must be prepared to accept a sequential 3 stage NOS kit (50kW; 75kW; 100kW stages)

The build will be a long term project as I only have around R3k per month (if I don't have other expenses to cover for that month). I want to do:

Planning
Sourcing
Machining
Assembly
Installation
Commissioning

Planning:
How do we do this?
What do we need?
What would be the best sequence of events to follow?
Additional enhancements other than engine? (clutch, brakes, fuel pump, drive shafts?)

Sourcing:
Which parts do we need to buy
Where to source the required parts from

Machining:
Cams
Valves
Crank
Balancing
Headwork

Assembly:
Installing all components and building the engine

Commissioning:
First start
Mapping
Dyno
Nos commissioning
Mapping
Dyno

Anyone know where to start? And how do I do this? :yes:
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #2
My first questions:
1. To what rpm and power output are stock conrods safe?
2. To what RPM limits are stock conrods safe?
3. Crank? 8000rpm? Just a balance or knife edge as well?
4. Pistons? Stock or forged?
5. Hydraulic valve lifters or solid?
 

·
Registered
Joined
·
4,196 Posts
Well, I'm being Captain Obvious here, but the first question to ask is whether the Busso head, running camshafts and valve springs, can at all do 8000rpm reliably.
I assume you'd have confirmed that this is the case, as otherwise you'd need to basically fit an entirely new head to the engine with a desmodromic, pneumatic or electric valvetrain.
 

·
Registered
Joined
·
1,928 Posts
Definitely solid lifters. You'll also have to go complete lightened bottom-end. flywheel, crank, rods, pistons alles.

Check out the 155 DTM video. I would go ITB's
 

·
Registered
Joined
·
2,694 Posts
Well, I'm being Captain Obvious here, but the first question to ask is whether the Busso head, running camshafts and valve springs, can at all do 8000rpm reliably.
I assume you'd have confirmed that this is the case, as otherwise you'd need to basically fit an entirely new head to the engine with a desmodromic, pneumatic or electric valvetrain.
the basic premise of over head cams and spring returned valves is good for double that.
solid lifters and maybe uprated valve springs for 8000rpm.

desmodromic valves require heaps of maintenance in terms of regularly adjusting clearances. they are cool on your ducati that you ride twice a month.
rotary valves are better.
 

·
Registered
Joined
·
1,928 Posts
Forgot to ask, where are you going to put this motor? Or are you going to rebuild the GTV engine for the GTV?
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #7
I have research showing that the 3.2 engine can rev to 8000rpm in road form and even stay with hydraulic lifters, which is both good news and a bit intriguing. I am just not sure of the mods required.

The reason for 8000rpm:
1. It maximizes power potential. Higher revs = more air through the engine. My engine is at a stage where enough air is getting in but I need my cams timed for higher rpm. My power curve is absolutely flat from 6300rpm to the 7500rpm limiter which means that if I can change the cam timing and phasing to move the torque curve higher up the rev range, then the power will increase
2. Higher revs in each gear = higher speeds in each gear = faster!!! :jester:
 

·
Registered
Joined
·
2,514 Posts
Your are going the expensive direction.

The limit on the std(any) conrods are with higher revs. It can take any amount of boost or Mean effective pressure. The least I will do is to change the conrod bolts to ARP bolts, but you really need uprated (read lighter) rods. NOS or turbo will give you more air in cylinder at safe std revs.

You will be toying with the limit of the std valve springs as well, if you use a cam with less than 10mm lift. If you use a higher lift cam start looking for uprated springs. On request I will explain how to check max lift for the springs.

11.5 compression ratio with a road cam, will give you a thorny stick to scratch the lions ball with. Sooner or later the knock sensor will max out and engine will detonate. You will need 98 to 100 octane fuel. You can go 12:1 with a 300deg cam on 95 octane but this is not for everyday use anymore. Adjusting cam timing require days on the dyno and a tuner with a brain. I am not convinced that you will win this test.

I would rather go for a 25kw, 50kw 75kw rpm controlled electronic NOS system, on full throttle only and a 10:1 compression (or lower) ratio. All the turbo dangers (read knocking first) apply.

See Dawie and have a strong car for a week.
 

·
Registered
Joined
·
2,694 Posts
you're looking at R20k + for a set of up-rated rods. And that's only to handle revs.
you can get a lot of power at standard revs for R20k.
 

·
Registered
Joined
·
94 Posts
Easy. My mate has this reliable with CPS Pistons ( 100g lighter) , PPM rods , 12.5 comp , solid lifters , definitly uprated valve springs s. Newman cams . Throttle bodies . Do not use 184mm clutch as they only last a few goes for road use .
Dawies Gta in production series touched 8300 a few times when downloading software .
So you need to start with £1000 for Pistons .
OR skip all the head work of solid lifters etc and just go 3.7 and your extra cost is block boring . You only need to rev to 6000rpm MAX and no throttles either . Very reliable from Dawie - my motor now still strong 10 races ( two heats so 20 races ) and five years of road driving . No head leaks or oil consumption issues ( out of the ordinary )
You end up with 194 kW on wheels .
Try find spare motor and build it up slowly . If you cant find a 3.2 use a 3.0 as that will probably Rev even easier . Remember that 156 coloni at Z , that was a howling 3.5 !
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #11
Can anyone answer the following questions then:
1. What is the maximum power than you can extract in N/A form from a 3.2 at normal rpm?
2. How will optimising for running at 8000rpm affect drivability? (Assume forged rods, forged pistons and solid lifters with race springs and 9.7mm lift, long duration cams)
3. Is possible to build a 240kW 3.2 engine and what would it take? (Flywheel power, as installed in the car and driving anciliaries like a/c; p/s; alternator and water pump)
4. How does cam timing affect torque curve? (Advance, retard, increased overlap, decreased overlap)

I have specific reasons for each question:
1. If I can get around 225kW from a 3.2 at "normal" rpm and N/A then I would be happy.
2. If I build a higher revving engine in mild tune but able to flow enough for the higher rpm then it would automatically make more power. I'll explain this.
3. I hope this can be done by increasing the rpm limit.
4. My understanding:
Advanced timing on both cams shifts peak torque to lower rpm
Retarded timing increases peak power at higher rpm (same as shifting torque peak to higher rpm)
Increasing overlap improves high rpm efficiency
Decreasing overlap improves idle quality

See small high rpm engines without variable cam timing or variable induction, but with torque peaks at relatively high rpm and therefore high power outputs at high rpm:

Example: 97kW Toyota 4A-GE after T-VIS units.

Power: 97kW @ 6600rpm
Torque: 148Nm @ 5800rpm

Double the engine capacity to double the outputs (1.6 scaled to 3.2 engine)
Power: 194kW @ 6600rpm
Torque: 296Nm @ 5800rpm

Real 3.2 Busso:
Power: 184kW @ 6300rpm
Torque: 300Nm @ 4800rpm

Clearly when you look at the Busso compared to the upscaled Toyota engine you realise that you can have a high revving engine with a substantial power boost, smooth idle, being relatively reliable but at the expense of peak torque and low down torque.

My satisfaction would be getting the ideal cam lift, duration and cam timing to have "almost" both.
And to have the hydraulic valve lifters that work in the 20V engines because they work at 8100rpm and higher.
And to be able to add nos when required :biglaugh:
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #12
Parts I planned to use:
Forged rods
Forged pistons
Race valve springs
9.7mm to 10.3mm long duration cams (nothing as bad as 11mm!)
Lightened flywheel
Lightened, balanced crank and rotating assembly
Headwork is mostly completed satisfactorily except for lifters and valve springs.

What else?
 

·
Registered
Joined
·
2,514 Posts
Do you want your 240kW on the crank or on the wheels? If it is on the crank, I do not see a problem, and it would be MUCH cheaper.

My assumption is that we lose 25% to the wheels, altitude take 11/2%(1% per 100m - fact). I did 231whp (231ckW) with std head and GTA2/1 cams meaning std 9.5mm lift(no need for uprated valve springs). 11:1 Compression ratio(piston 0.4mm higher than std), K+N and home brewed exhaust. Adjustable Fuel pressure regulator and UniQ.

Later I did 228whp with same set-up, flowed valves and seats but with GTA1 cams both sides.

In comparison, Gertie did 205whp with his 3 ltr with GTA1 cams on both ends. That means still no expensive tinkering and reliable everyday road cars. Unless MRD runs a GT dyno.

Bradley wouldn't tell us what the GT racer is doing on the dyno. They run a 300deg cam, worked head. There were statements that the block is std, which I take tongue in the cheek. They run 8000rpm and needed an uprated clutch. So the torque is way higher than std. Unfortunately I could not get a lift in it at Kyalami, they were doing set-up on the car. Maybe on the ARCOP trackday.

I stick to my theory that a turbo on a unmodified engine apart from lower compression and uprated clutch, will do everything you need, with much less unknowns. At 300ckW the turbo is very turned-down. Hennie did 400whp(400ckW) on a high compression set-up, which is more dangerous. In daily tune he run it at 365whp(a horse for every day of the year) The problem with this much horses is the fwd, which in his case, is kept tame by the traction control.

There is a 390wkW turbo GTA in Gauteng, running forged pistons further std engine built by Emil Andreata with pipework from vd Linde.
 

·
Registered
Joined
·
2,514 Posts
Parts I planned to use:
Forged rods
Forged pistons
Race valve springs
9.7mm to 10.3mm long duration cams (nothing as bad as 11mm!)
Lightened flywheel
Lightened, balanced crank and rotating assembly
Headwork is mostly completed satisfactorily except for lifters and valve springs.

What else?
A big valve head (opened ports similar to a 3.7) and you will need a calmer cam which is better for the road. Find out who did the GT racer, do the same with a calmer cam like the super boss profile(276 deg @ 10.6mm)
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #15
Now that we know that my GTV has a bearing knock, this project will go a bit slower than usual. I first need to sort out some other major expenses in the meantime:

Brakes for the 159. Dealers quote R11k, and R15k including fitting. I'm thinking of getting me drilled and slotted discs instead, as well as performance pads. For R6k for the lot :cheese:
Engine for the GTV: R45k for a motor in a crate + approx. R3k for fitting.

In the meantime I'll be buying my engine upgrade bits, and polishing them every few weeks or so :biglaugh:
 

·
Registered
Joined
·
4,528 Posts
What does the forensic work suggest happened to the motor, Ian?

Sent from my SM-G925F using Tapatalk
 

·
Registered
Joined
·
10,929 Posts
Discussion Starter #17
What does the forensic work suggest happened to the motor, Ian?

Sent from my SM-G925F using Tapatalk
The car's still parked at home. I have a few other financial commitments to complete first, unfortunately. Like brakes for the 159, and then seriously reducing my other debt.

I seriously am beginning to suspect a level of oil starvation on that engine because:

1. Cam lobe wear as indicated during the head rebuild.
2. Collapsed tappets as indicated during the head rebuild.
3. Bearing knock.

The tappets were replaced and cams rebuilt and reground, but perhaps the bearings took a while longer to display their misfortune.

This therefore points to a long term event. As far as I know the oil levels were always correct and there never was an oil light under any circumstances. I may need to have the oil pump checked and then have a new one fitted. Or perhaps the overheating engine caused the oil to sludge up and starve the engine.

Maybe I just drive the thing too hard on mountain passes and get oil starvation that way? Might need to install baffles in the sump too then. I'll let you know as soon as the motor has been removed and taken apart.
 
1 - 20 of 51 Posts
Top