Rotus Project Build

Jamie R · December 04, 2018, 01:34:57 PM

Hey Boosted

You mentioned losing the air pump which is fine, I had relocated it, and modified pieces on the valve for more clearance on the headers.

That's not an issue I bought a stainless exhaust manifold flange from Clive earlier this year and can blank the hole up.

Looking through the manuals, I've noticed ancillary parts like on the pics below, charcoal canisters and some EVAP doo dahs that if I remember correctly sat under the boot floor high up above the diff.

Can this be junked as well?

Ive ruled everything in at this stage so I can rule it out, like my Decat pipe, I can run the standard Cat in the engine bay (pic attached) between the engine and bulkhead, it bolts to the bellhousing and thought just in case Mr. MOT inspector wanted it, its 7 bolts to swap it out.

If you can think of other stuff I can junk, just shout ..........

boosted · December 04, 2018, 01:39:23 PM

Yeah easy sport really picking off cars leaving shows....but with youtube and this craze of leaving shows doing burnouts and drifts that everybody films and sticks on youtube im not surprised...
Problem is locals quite rightly complain and thsts another circuit shutdown...!!!
Defo go the road legal route excellent for shaking down before a trackday...mines got a daytime mot..its a pig on road and very worried about the sump hitting mind.

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boosted · December 04, 2018, 01:50:29 PM

All the canister stuff can go. Just remember to cap any vac lines on the plastic intake manifold.
Mot wise...Elan is precat 92 so im 99% sure wont be needed. All the new regs ar 2006 onwards.
I have no cat as car is a Q plate! Emmisions exempt booyar! I also got it sucessfully registered as a 1300cc so cheaper tax. 3 attempt with dvla mind.
Id considered wrapping the exhaust crossover pipe...its gonna get very very hot...ive burnt my leg several times on mine!
I think with a cat in that place you could probably melt the intake....serious heat and noise is rotary!
Mine tests static noise test between 92 and 94dB with a 9" repackable silencer from Torque Techniques in Salisbury...its not got any louder...he said quote" argghh Rotary i know what cloth to use from my Janspeed days" ..silencers been great.
No cat equals flames!!!!

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Jamie R · December 04, 2018, 02:03:13 PM

Well Im hoping the Elan is tax free anyway lol ! The Mk1 escort and 1947 Chevy Truck were and they had engine swaps.

Im not fussed about the loops holes of the system, if I get stung, Ill have a track day weapon, just trailer it everywhere.

Whats your view on the decat pipe? (pic further up the post) I have no room anywhere else for an exhaust without chopping my legs off, the front wheel axle line on your westy is a bit further forward than my set up so your headers come straight out the side and I cant move my engine back any further.

I did plan on ceramic coating the hole engine bay with that sticky backed stuff, wrapping the exhaust although I think it looks hideous and having serious vents in the bonnet to let the air out.

Was trying to get clever with bonnet design and drawing radiator air out the front of the bonnet and another inlet and outlet to allow incoming air to draw the hot air of the exhaust out. Bit like that vent you have behind your air filter on the westy.

Ive seen plenty of videos on the web of glowing red exhausts on 8's and 7's so I thought with the location of the cat or the decat pipe its like a windscreen de-icer for the winter lol.

boosted · December 04, 2018, 03:03:59 PM

the decat looks fine to me it wont get anywhere near as hot as a cat...the cat it that position does concern me i think you'd have a fire.

The radiant heat from the cat is immense.

The specialist coating zircotec would be awesome but doing the manifold and decat pipe would be alot of dosh i think but would be epic in controlling the heat. I know the wrap is unsightly but it does work. I think braided fuel hose in the engine compartment would be safe choice.

Youve got to work with what room youve got and the manifold is ace, nice flowing bends and big bore so should be fine, just the heat to deal with.

where the steering column on your car? I have to remove mine pulling/fitting engine? as inlet and manifold over under it.

Jamie R · December 04, 2018, 03:13:24 PM

Im in the same boat......

2 headers loop under the column, 1 loops over it.

No decent pics of it yet.

Ive got pie cut exhaust headers all the way up to the collector, some parts are only tacked and there are only tacks on the manifold flange.

Cant finish it till the engine comes out.

Back to the column......that will be heat shielded too,

re japi · December 04, 2018, 03:27:41 PM

Jon had good point there, exhaust is super hot! Then, N/A rotarys are really really sentive about headers. Can compare 2stroke tuning, you can lose or gain lots of power with crappy exhaust...

Also, you need to figure out how to get maximum air flow to radiator and oil cooler(s). Rotarys are really sensitive about those. Water cools about 70% from engine massive heat, and oil cools rest. Howerer, in rotary oil needs to be really good and in good temp...

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boosted · December 04, 2018, 03:41:10 PM

Somebody on rx8club said my exhaust manifold was rubbish! Dont know enough about exhaust tuning to disagree but if my straight out headers 1 bend each into a 3 inch straight through silencer is worse than the stock log manifold id be very surprised...
There was talk of unequal length is best to accomodate the exhaust pulses but at 5000 to 9000 rpms thats 1 hell of lot of pulses and unequal or not there gonna collide at the collector unless your a maths genuis ...my take would be you got to work with what space youve got and try and make it as free flowing as possible, which i believe mine does. The stock rx8 manifold is a brick wall for gas flow but Mazda had to work with the space they had.

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Jamie R · December 04, 2018, 03:44:00 PM

That's an interesting point.

I've had opposite feedback about the headers on the RX8 because of the side port and its not as sensitive as the RX7 with peripheral ports.

I've designed and built a few expansion chambers for 2 stroke bikes, and yes I take on board your point.

Look at the standard RX8 manifold, its rubbish, the front port exhaust gas has to travel much further as a percentage compared to the rear port before it gets to the cat.

I emailed Racing beat in America, and they said they had run several different options on header length and when dyno'd made little difference because of the side port and you don't get the same benefit from the "pulse"

So from experiences, I've made the exhaust headers long enough to make them work practically and a lot of people in the 4 stroke world like "equal length headers" but some are as much as 10" difference in length. I've managed to keep all 3 headers with 100mm of one another just to balance things out as near as I could.

And yes I've heard that too about the oil coolers. I've stuck with the stock ones as Im only going for a Bridgeport and an Adaptronic ECU in terms of tuning, so im happy around the 280 Bhp mark if possible.

The bumper will be custom made in fibreglass too, and will probably resemble a fish with a gaping mouth LOL. I don't have any constraints in terms of air flow into the radiators, but more about room getting the air out, which is equally important.

I do appreciate the feedback though, its good to share stuff as it leads to good ideas.

Jamie R · December 04, 2018, 03:46:08 PM

I think ive just echoed Jon's post there LOL

Jamie R · December 04, 2018, 04:24:39 PM

Just read back on my post, and it sounds REALLY condescending reading it back.

Apologies if its rubbed anyone the wrong way.......... tone and context is difficult to express in text!!

Was just trying to be informative

boosted · December 04, 2018, 04:50:45 PM

Did not come come across that way to me so dont worry.

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re japi · December 04, 2018, 06:26:25 PM

Yeah, and I dont understand anything anyways

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re japi · December 04, 2018, 06:33:19 PM

As for headers, I dont know much about renesis headers. But yes, exhaust ports are very restricting and narrow. So I would imagine that good flowing header is much easier to build than stock one.

Howerer, theres much tests and tips how rotary headers for Peripheral exhaust should be made. One key tip is that first you go with straight pipe for 5cm and only after that can first curve begin. Also, there is few best choise of header leghts. But what I have found out, many will build too restrictin collector...

Im sure that Hayward knows best lengts for Renny headers. But I think aftermarket like RBs are really good too

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boosted · December 04, 2018, 06:48:41 PM

Yeah Carl started explaining it to me once i nodded approvingly and i think he thought i understood but it was abit lost on me...lol
Then I had a conversation with Clive about exhaust gas scavenging again i got the jist but yeah but no but...lol.
Just get in and floor it....if it feels fast happy days.

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