Thread: Project Roverkill D2a

Originally Posted by turtle

"This valve is vacuum controlled, a vacuum line runs up into the engine bay and meets a solenoid that feeds of the intake manifold. I have a small switch next to the gear shifter that controls the exhaust valve."


Just a question re controlling the exhaust valve. If you are accelerating heavily and your foot is to the floor, won't your vacuum drop to 'very little' in the manifold and then you would lose the control signal? This would then close the valve and you would lose the benefit of having a 'free flowing' exhaust.

Foxy

A small vacuum reservoir and a non return valve on the vacuum line fixes that. No different to a brake booster.

Originally Posted by turtle

"This valve is vacuum controlled, a vacuum line runs up into the engine bay and meets a solenoid that feeds of the intake manifold. I have a small switch next to the gear shifter that controls the exhaust valve."


Just a question re controlling the exhaust valve. If you are accelerating heavily and your foot is to the floor, won't your vacuum drop to 'very little' in the manifold and then you would lose the control signal? This would then close the valve and you would lose the benefit of having a 'free flowing' exhaust.

Foxy

Hi, Yes you raise a good point. I failed to mention i have a check valve between the manifold and the solenoid for this reason. The valve is just off a Japanese 4wd, i believe a Toyota surf (those cars have a gazillion vacuum lines).

Nice Build! Good to see custom fab on a D2

Where did you get your headman headers from?

Originally Posted by D2_TD5

Nice Build! Good to see custom fab on a D2

Where did you get your headman headers from?

Hey thanks mate. Yes i enjoy doing some handy work with the welder etc. I am deciding whether or not to sell the ARB bar and custom build a front winch bumper or just modify the ARB unit... I i like the idea of a custom built unit, we will see.

Hedman headers were from JEGS in the States. Hedman 39800: Standard Duty Uncoated Headers | JEGS part number 39800

unfortunately they are not a direct bolt on. Test fit the headers and then you will likely find that each runner (just after the exhaust port on the head) needs to be pie cut and welded a small amount as to pull the bottom of the header away from the chassis rail. Once you test fit/modify them then i would recommend to have them ceramic coated like i did. I recommend getting the "sandwiched" type of header-exhaust port gasket, these gaskets are the best for this header. Do not use the gaskets that come from the box.

Pros of these headers:
-i could feel a power increase in the top of the rev range, the car is happy as Larry to sit up in the 5000rpm range, good for sand driving.
-because of the 4 into 1 configuration the car now sounds like it has a small, small block chev in it .

- i could not feel a loss in low down torque (everyone said i would).

Cons:

-mediocre build quality, light wall tubing.

- after you factor in the ceramic coating, they cost as much as any other Australian header on the market. (although the Aussie headers are not 4 into 1).

- added engine noise. The light wall tubing transmits a lot of exhaust sound.


Hope that helped.
-Blair

below you will see the relief cuts and welds that i did to make the headers fit. I only realized it needed to be modified after the ceramic coating.

Cool, thanks for all the details! Cant wait to get stuck into the Rover V8, I rekon with the right mods and tune it could make some decent grunt and be some what economical, for what it is anyway.

Are you planning to get a tune?

Originally Posted by D2_TD5

Cool, thanks for all the details! Cant wait to get stuck into the Rover V8, I rekon with the right mods and tune it could make some decent grunt and be some what economical, for what it is anyway.

Are you planning to get a tune?

Being honest mate these engines seam like a dead end, hate to burst your bubble. Have your fun however don't bury to much money in to one haha. The max i would do to one is some headers and a camshaft... that is about all i have planned for this engine. If i want more power/reliability then it will be engine conversion time

From my research it appears that the Bosch m5.2.1 ECM is not able to be tuned easily. Its not all bad news however because the stock tune already has a considerable amount of leniency when it comes to air fuel ratios. The closed oxygen sensor system will cater for camshafts, exhausts etc. You may be able to get away with a few mods and the ECM will adapt to the new engine parameters (with more fuel). I have known a few blokes who have put a 4.6 crankshaft into their d2's and the stock ECM caters for the increased need for fuel just fine.

cheers,

cool, be keen to see the graph if you ever put yours on a dyno.

I guess that's probably the reason I couldn't find much on modding the Rover V8 unlike the GM LSx engines! Should have a bit of an idea in the next few months what I can get out of it. Gotta sort a dead MAF issue first

I have a 4.6 high compression in my D2 manual with stock Bosch EM and injectors and it goes very well and with good economy.

Mate what a great thread - your build up is something to be proud of. I did an inline thermostat and it has been excellent. Yours looks neater than mine. Would you mind posting up the component details including hose numbers and types and joiner that appears to have the bleeder in it. I have a TEFBA Filter that complicates my set up (maybe mine cannot run like your set up due to filter). Mine works well and had been there for quite some time and a hell of a lot of corrugated roads so I should leave it alone... Cheers