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Sizing of Exhaust Pipe Turbo to bumper - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums #ForTheOwners Jump to content


Sizing of Exhaust Pipe Turbo to bumper


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Hey Fellas,

 

I am back on the road for now! Only $1400 to clear the last shop effort!

 

1) A/C works now after Sportscar Shop found the leak, O-rings on the Schrader valves on the Compressor, something Treasured Motors could not find after three attempts and $320 looking.

 

2) Radiator Fans now work. Bad relay.

 

3) Passenger window now faster up than the Driver Window!

 

4) Beautiful Door Sills installed.

 

5) Passed its MOT in my new state of Delaware and now registered there,

 

and more.

 

Now the plan for this Winter is to rid myself of the CAT, install the new electrochromic rear view mirror with temp gauge, compass and down light. Due to having a larger turbo on the car and the fabulous Alunox header installed, I am thinking about enlarging the tailpipe to 3" or larger. The current shop has a rolling road available for $150 per tuning session so what would be your thinking on sizing it or just wait and see what comes of the rolling road then? i do NOT know what turbo is installed but I do sometimes see 1.22 Bar on rug touching in first and sometimes second so it is a bit larger than stock. It was sold to me as a WC Engineering Ceramic upgrade by Jamie Goffaus (now defunct Yesteryear Motors) but John says no, not his and can not identify it. Yes the boost controller seems to still keep it from going higher than 1.01 normally....

 

my choice would be a Stainless set less Cat from the V-Banded Turbo back to a single outlet on the right side as was stock (US Federal). Cheers for now. Am playing on the roads this week.

Ideas anyone?

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Hey ho Travis!

 

Thank you for your pics! Perhaps I am confused then, not having the car at hand until later on tonight I thought the rebuild had a V-band connection to the exhaust pipe rather than the Alunox header, perhaps I am reversing it all, again, lol. Did the V-Band to R&R the De-Cat pipe if necessary for future MOT's. Maybe a V-band to the Alunox but I think it is on the down pipe side. I will know which side rests the V-Band when I get to the car around midnight. Will post more tomorrow when I get back here from Delaware. Either way, what say you to up-sizing the exhaust pipe for freer breathing for the Turbo?

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Mikie,

Congrats on having your car on the road and problems solved! Great news  ;)

 

Just for inspiration: when I canged my standard cat and related pipe to a free flow and 3" pipe on my Corrado G60, I got a lot more HP's. 12.

I have bought similar parts for my SE, but will not do it untill this coming Winter.

 

Mostly, gains will not step into effect, untill more parts which also give a greater outout etc, are Applied and can Work in sync.

 

Did someone install relay for the passenger side window?

 

Cheers,

Jacques.

Nobody does it better - than Lotus ;)

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hey all,

 

Bad news. It rained the entire time I had with the car so it went no where but i did check to see if the A/C was still cold - it was! Windows was cleaned and greased and switch was lubed with contact cleaner. Goes up faster than driver side now!  V-Band is after turbo so should work to an upsized cat pipe, etc. But to what size? 3, 3.5 or 4" I dunno. Jacques, stuff done to car: uprated turbo but completely unknown type, style it is cosworth type with full bearing though, larger and balanced injectors (all 6), S4s + 3% Chip from WC Engineering (John Welch), Alunox header, K&N air filter, green dot cam pulleys, ram air on the list, LSD, So there is potential need for better breathing and less back pressure I think. 

 

MikieP

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Not working of Lotus Esprits, my friend WHO have tuned vw and audi's for more than a decade, as his everyday job, have used 3.5" tubing for up to 500 Hp, and 4" for up tp 700 Hp. Then he also made some Electronic ports that open beyond 3000 rpm. Mostly bi-turbo setup's.

 

Anyway, your car should really move forward with that setup. Have you thought about a dyno test to keep track on what's happening when doing what?

 

Kind rgeards,

Jacques.

Nobody does it better - than Lotus ;)

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Hi Jacques,

 

Sounds like I am then looking for a 3.5" exhaust system from the turbo back then? New shop has access to a rolling road for tuning and that is perhaps on my winter work I am thinking of getting done if the car has no other issues by then. They say they can make one up without the crushing bends some places put into the bending of the pipes but cost is not known at this time.

 

MikieP

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Mandrel bent pipes?

 

Yeah, some years ago, when I bought a set of bigger stainless downpipes for my Laverds sfc1000, they did not fit correctly, so I took the pipes to a friend, WHO have this sort of equipment. It's a giant machine with a lot of various big round discs, and you insert thepipe in between and slowly bent then into shape. Worked a treat and no ugly wrinkles etc.

 

What is your target regarding horsepower? That would give an indication for the sizing of the pipes.

 

Cheers,

Jacques.

Nobody does it better - than Lotus ;)

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Mandrel bent pipes?   What is your target regarding horsepower?

 

Valid points,    Your target HP could be achieved with 3" but 3.5"  has extra benefits..   By creating a bell mouth straight after the turbo into a larger pipe you can generate a low pressure zone post turbo.  this will assist spool up and help reduce lag..  If you are using the standard secondaries / collectors on the Alunox system then the velocity created by these will be complimented by the bigger out let..  (The bigger the pressure difference across the turbine the better..)

There are many factors that need considering when looking for BHP  air flow being primary. By addressing this exhaust area correctly it will not be found needing later... I use a 3.5" system with straight though box without issue..  

Hope this helps with your decision

 

HPIM3999.JPG

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Hi Dave,

Much thanks for your input and drooly pics! Alunox is the manifold to the Turbo which has a V-Band connection to the rest of the system. EBV valve is gone and thinking the cat should go as well as I just passed Delaware state inspection three weeks ago. Not sure of what muffler to use, but I do need to keep the noise within social limitations due to where I live. Your setup looks soooo sweet. Seems like a 3 1/2'" system would be the size I should give someone to make up then.

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  • 3 months later...
  • 1 month later...

There is BeHe in Beltsville, MD and the shop in Sterling told me there is one they use near their shop but I do not know the name as yet. Still waiting for their new shop to be set up to bring my car in for several tasks... MDS in MD can do up to 3" mandrell bent exhaust pipes but I have yet to take car there to get pricing....

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