Thread: Improving TD5 performance. exhaust query

Have been muddling along replacing warped TD5 manifold.
Muddling along because my real tools are 2000k's away in my workshop and there were broken studs, rounded off nuts and even AF bolts screwed into metric holes on other parts that had to be removed.
Was sold a set of 10MM studs (with flanged nuts).
8 x10mm and 2x8mm studs and nuts in PKT, as there is evidently not enough meat on the middle exhaust port to accommodate replacing centre studs with 10mm.
They are a BritPart Package part TE110051L Googled that number with "stud" as prefix and sellers show up

I note the earlier comment on enlarging the manifold bolt holes to allow expansion, seems I might have inadvertantly achieved that because with having to drill and extract broken studs, I didn't exactly get the replacement studs to line up like originals. My solution was to enlarge the manifold holes, so maybe I have got lucky.
Of course now there might not be enough meat around the bolt holes and the manifold may break as it tries to warp.

Will likely look to ceramic coating of manifold and see a mate who does cylinder heads and porting to see what he reckons about altering manifold.
Still wondering about SS extractors, but enlarge the bolt holes (to allow for metal expansion) and ceramic coat them as well to assist with heat. (Will put that down for alater day.)
Have checked with 3" exhaust manufacturers (Genie), they report 2.5" until flexible section then thay expand to 3" on other side of flexible.
My service person reckons no need for full 3" system, just remove CAT and big muffler and replace with free flow pipe and remap ECU.
Reckons IC is good enough for that level of modification.
I just want it to pull better and run cooler.

I will get an EGT guage installed so I can see what is going on with temp.
I often have to do long hot runs (10-12 hours in 40C+) and it may just get hot from that alone, and still require a bigger exhaust if that cools things.
I have a madman engine and trans temp monitor on other TD5 and that is very helpful.

Originally Posted by PhilipA

I think that an EGT gauge is the most important gauge for a modified TD5. A boost gauge is helpful if you want to set and control boost above 15PSI.

Mine is fitted at the dimple on the exhaust mainfold just in front of the turbo.

I think it cost about $120 for the ceramic coating but I also think that it was a cheap price done in Wyong by Wyong Powder coaters.
The flatting of the manifold cost $100 and I dewebbed it and elongated the holes myself.
So far 40KK and no problems. I also fitted Mercedes studs with belleville washers .
The ceramic coating keeps the heat in the manifold and insulates the manifold from the exhaust gasses. It is primarily a reliability thing.

The EGT gauge is not just to know what is happening. It is a primary management device. when you have a modified motor you tend to drive by it up hills while towing. Even with no mods I think the EGTs would be excessive if you drove flat to the floor in a high gear. This was reinforced to me recently when I towed my daughter's camping trailer up a steep hill. the car was pulling well in locked third but the EGTs flew up to 750. I changed back to second and eased off and they dropped to 650.
Regards PhilipA

Checked with Genie QLD who make the 3" SS exhaust for TD5.
They report that it remains 2.5" until after flex section, then it expands to 3".
I'm going (initially) with recommendation of my service perosn who says just put straight through pipe from exhaust flange past big muffler.
He insists that is sufficient.
So will try that first, as I just want improved pulling and performance, and that may be adequate for what I expect.

Originally Posted by Slunnie

My thoughts, in modding an engine you should be working to keep the EGTs down. Larger intercoolers bring EGTs down and increase power, my thoughts are that they shouldn't be an "if needed", especially if the ECU tune is being altered for more power, which will increase EGTs. If something brings the EGTs up, something has to bring them down again so you don't have a hot engine that wont allow you to use the HP when towing or on highway hills.

Yep EGR, easy done.
Extractors, as in true extractors I've never seen for a Td5? Fabricated manifolds that I've seen I wouldnt have called extractors, but they sound good.

Exhaust, from what I understand, the biggest choke is in the flex on the down tube, the rest is ok. I've tried middle muffler in/out and noise was the only difference I could note. The only Td5 exhaust system that I've heard about that actually does make a tested real difference is the TaiwanXP system. I'm pretty sure it was DPL that tested it and raved about it and I think Tombie may have tested it also. It comes out of QLD but I've just seen Perth dealers.

Landrover Discovery TD5 Wagon - 4WD Performance Exhaust Upgrades

The transition in pipe size should blend sizes just after the turbo, it shouldn't step up, that wouldnt be incredibly crap design to do that. Manufacturers and builders go to a lot of lengths to port match to increase efficiency and power, a step in the exhaust system would be a big move in the opposite direction.

Originally Posted by simonmelb

Hi Phillip,

Do you have any part no’s or details on the Merc studs and washers?

Mine is overdue for a fix with slight leak at the exhaust to head connection.

Thanks
Simon

Pretty sure I still have a spare manifold here if you want to get it done without taking the car off the road for days. Happy to give it to you on a swap basis if you like.

I'd better make sure I still have it first though I guess,,,,,,

2.5” (stock) exhaust is good for 200+hp without a problem with a good muffler set up.

As for Manifold - do not be tempted to look at a SS fabricated unit. It will crack and fail. If you want a better unit there is a cast one with a nicer runner set up available.

Originally Posted by vbrab

Checked with Genie QLD who make the 3" SS exhaust for TD5.
They report that it remains 2.5" until after flex section, then it expands to 3".
.

Nope, it's definitely 3" just after the dump and before the flex, unless they've changed the design in the last six months.
Refer photo above.

Originally Posted by Tombie

As for Manifold - do not be tempted to look at a SS fabricated unit. It will crack and fail. If you want a better unit there is a cast one with a nicer runner set up available.

I'd love to see the Allisport one dynoed against a stocker as visually I don't like the transition into the single runner pre turbo

I run an allisport manifold and JE studs with cost $230 delivered and it works great, no issues at all, the top setup cost was $1500 for the two