3428TM Build Log

[my250gt]

Hi SlowM, what body mods are you contemplating to cover that wide rubber? Are you going to fabricate to suit the tyre or have you got some arches sorted already?

[Slow M]

my250gt said:

Hi SlowM, what body mods are you contemplating to cover that wide rubber? Are you going to fabricate to suit the tyre or have you got some arches sorted already?

I am thinking SE arches. On the back the addition of a "fence" should help abate lift, and at the front, i may extend the leading edge of the nose, and radius it, slightly, to add downforce. A splitter will help as well. Also, venturi under the tank are a thought.

Best,
B.

[Slow M]

Made a couple of varaiants of the dry sump pump bracket. Early one shown below.


Axles and driveshaft arrived, but axles had wrong CV boots installed.


A few emails later ...


Will attempt to install this weekend.

Best,
B.

[Slow M]

Tried wrestling the axles into the uprights that were their intended home. Outer CVs were discussed to be 100mm at the widest point. they ended up at 104.5mm, and so they've crossed the USA once again.

While I'm not happy about all of the additional work on my part, I'm impressed that there are people who don't try to wash their hands of a losing proposition.

Best,
B.

[Slow M]

Rumour has it, third time's a charm. Trying again this weekend.

Best,
B.

[Slow M]

Axles are in.
Rear suspension is back together.

Next, I'll have to bolt together as much as I can. I move to California before the end of the month.

Best,
B.

[ivanhoew]

nOOOOOOOO....where am i going to get my tvr project fix now when i come to van !!!???

[Slow M]

Don't fret, Gregg's become the RO for the TVR club, I imagine he should be able to drum up something for distinguished visitors to see. Jarred Swalwell's also been working on his M.

Any plans to visit California?

Best,
B.

Edited by Slow M on Saturday 8th December 03:24

[Slow M]

I askked my brother run the Engine Analyser software on my combination with less than ideal header lengths. I estimated that I could have 18" primaries, if they turn down to a collector. He found that the result is a loss of over 40HP, and an erratic power curve. As I have to sharpen my CAD skills anyway, I designed a custom header flange for the AFR heads, and drew it up.

Best,
B.

[Grantura MKI]

I have a contact that can help if required?

[Slow M]

Grantura MKI said:

I have a contact that can help if required?

D,

Thank you; I'd be grateful for any contact information, but unfortunately, anything that absorbs funds* is off limits to me, until I manage to find work.

* Aside, perhaps, from a TVRCCNA membership.

Best,
B.

[ivanhoew]

bernard ,have a play with both pipe length and diameter in eap ,should be possible to find that hp back by using a different hatmonic .

rr

[Slow M]

Hi R,

I hope you're well.

We played around with PipeMax, and with Engine Analyzer. They both agreed that the diameter should be 1 3/4" (PM allowing as little as 1 5/8"). PM called for primary lengths to be 27.2" to 29.8", while EA made them 28"-30". I can make that happen, if I go with a system like this.


The next harmonic down is at roughly 19". Will get Oliver to run the numbers again at that length, when he has a chance. Will let you know what the drop is at that length. I might be able to make that happen by routing the primaries down and back, and placing the merge collectors left and right of the bellhousing. Later on, when I feel like a glutton for punishment, I can try the long way 'round.

Best,
B.

[Slow M]

R,

Good call! Looks like there'll be no need to add even more mass, heat, and complexity. 19" will do just fine.

Best,
B.

[Grantura MKI]

Ah, spagetti pipes. Love the sound. Are you wrapping them and any plug lead issues?

[Slow M]

To be honest, I don't even know where this stuff is supposed to fit. I hope not to have to be doing the forward facing "bundle of snakes," but I also can't imagine how there will be enough space if I try to route the pipes down, on the right side of the motor. There are oil pipes, starter, and dry sump pump that also share the space, not to mention engine mounts.

I need a sonic srewdriver.

Best,
B.

[ivanhoew]

nice job bernhard ,

you could also try different primary lengths for different torque peaks from each cylinder ,getting a broader power band, albeit with a lower peak ,this might let you run the pipes without having to try for equal lengths .
another thing to play with is the secondary length and diameter .

fun fun fun !

regards
robert

[TVR_owner]

ivanhoew said:

nice job bernhard ,

you could also try different primary lengths for different torque peaks from each cylinder ,getting a broader power band, albeit with a lower peak ,this might let you run the pipes without having to try for equal lengths .
another thing to play with is the secondary length and diameter .

fun fun fun !

regards
robert

Or do what Ductai do. Their exhaust desigh is compromised when it comes to equal primaries by engine configuration so they run different ID exhausts front cylinder and rear.

Here are some (poor) shots of a forward routed system in an M with a V6, its not too busy but guess it depends what the relationship is between top chasis rail and exhaust ports.

Edited by TVR_owner on Saturday 26th January 12:40

[Slow M]

Wow! Thanks; there are some great thoughts there. I know that Honda played with using different harmonics on different cylinders on their late 60s Formula One V12. As I recall, they had longer intakes on the middle four cylinders, so I'm sure they used the exhausts to that end as well.

Oddly, diameter does not seem to matter, as far as the harmonic length is concerned, at least as far as PipeMax is concerned. It gives an approximate range of volumes.
"ID = 1.481" to 1.606 Length= 27.2 to 29.8 inches long." Even with a stepped header, it still arrives at the same range of lengths (placing the steps equidistant along the primary tube/pipe). That allows for a range of primary pipe volume from just under 47CI to over 60CI. ... ... ...

So, I suppose, the next trick would be to still have sequenced pulses rotating around the collector in some sort of regular pattern.

Thanks lots, gents!

Best,
B.

[Grantura MKI]

B,
Sorry for a lack of reply. My home PC has been acting up and is currently in hospital. I did not want to spread any virus', so no out going messages were sent.
Regards,
D.