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Discussion Starter #1
Question please!
So if faced with the cost of rebuilding the original Garrett T3 from my 93SE, should I consider replacing it with a GT3071 which I also have?
The 3071 also needs rebuilding so either way I'm going there.
Changing from a Journal bearing turbo do I require anything else for a Ball bearing install?
I'd prefer not to change the Chargecooler for a larger one at this time. I know this has been done by some other members.
My car was chipped by PO who couldn't remember where it came from but it's not a super high performance one.
Guessing original ECU.
Aftermarket BOV.
I have aftermarket primary injectors from Five "O" Racing, the original secondary ones and I'm using the K&N air filter.
Headers to CAT all original, aftermarket muffler tail pipe.
I've given the above details as I've read the ECU, fuel flow, exhaust flow will all go out of wack and these other areas have to be addressed at the same time??
I'm not looking to push the performance envelope here, I'd be very happy to see a modest performance improvement and maybe with the exception of the secondary injectors I really don't want to change anything else just at the moment.
So can I just change the turbo for now and would it be worth it?
Thank you!
 

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a ball bearing turbo requires an oil restrictor. This fits my GT3071R
ATP-OIL-021*** -4 size Oil inlet fitting for GT28/30/35R with built-in restrictor******** *** *** *** *** *** *** *** * 1******* $12.00*
 

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Integrator
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2,805 Posts
FYI:
https://motoiq.com/nerd-o-scope-honeywell-garretts-g-series-turbochargers/


IMO, GT3071R, at PR=~2.0, is too close to the surge line (onset of boost may be delayed). Even 56 trim looks not too bad, but 58 is dicey.

I think you'd be better to send your old turbo to CompTurbo and ask them to rebuild it with water/oil 3x ball bearing CHRA,
their own Inconel 713C 10 Bladed Turbine Wheel,
ask for billet comp wheel and max out your compressor to Super 60, it'll look "stock" and flows 34lb/min,
or
let them attach their own compressor, but not larger than .46 a/r.
Do not machine the exhaust exducer port, this area is too thin and prone to cracking.
CT Turbo has 30% off sale in March
Cheers
John
 

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Discussion Starter #7
Thanks Mr Dangerous I'm educating myself as I go down this path sorry to say much of the technical spec you sent is beyond me at this time. Certainly turbo lag is one of my complaints although it's fun when the power comes on, it reminds me of my 2 stroke motorcycles riding in the powerband many years back. I do get that this might not be the best fit. I was sort of hoping to make it work based on the fact I already have it. If I were to upgrade/repair the old T3 new go ball bearing and Turbine wheel could I expect/notice a performance improvement?
Also if I were to go bigger chargcooler and secondary injectors, billet turbine for the 3071 would that be enough to consider it?
 

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Remember to look at the fuel pressure regulator and the fuel pump as well, if you go to a larger turbo.
On the Sport300 Lotus used a larger turbo, another ecu, a better pump in the right hand tank and a modified fuel pressure regulator. They kept the chargecooler standard, apart from a 10mm cut off on the inlet side, to adapt the larger turbo.

On a secondary note, the following may be of interest to you, if you upgrade the turbo:

An adjustable fpr may be the way to go for you. Also, at that point you may want a better exhaust manifold, say an alunox one, which flows very well. They are at their 3'rd generation, so they do optimise over time. This flows far better and can follow any upgrade you may do, now or later. Then comes the cat, which should at least be investigated for flow, as they get old and bits fall off and restrict the exhaust, which may have consequences. I used a slightly larger more free flowing cat and it's stil street legal and cleans the exhaust gas and pass inspection.
In connection to this, you may want to look at the mechanical chargecoolerpump, which could be changed for a more reliable electrical one. Lot's of threads with a discussion on that topic.
At that time you do want to install better brakes, if not already ;) Some good Guys over in the UK developed a kit to remove the abs system, as the old one installed seems to develop some problems over the years, for example because of not changeing brake fluid every year or every second year. The later abs system as on the 2 Liter GT3 had a more modern faster better reacting system.
You may of course, have done all of the above already.

Let's hear what you decide on and to what effect.

Cheers,
Redfox
 

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Integrator
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Mr Dangerous trying to understand the AR and trim numbers on Turbos the info you sent on the GTX2086 is it the same specs as the pic I will enclose please?
This turbo is "too big". It will give you a sudden (and late!) onset of boost at the higher rpm range. Good for racing/track. Your street driving will not be pleasant, power delivery will be quite abrupt making the car difficult to drive "in Town" (acting like ON-OFF switch).

As a reference, the ultimate 4-cyl Lotus s4s has 0.48 ar turbine cover and 0.42ar comp and it runs like a scalded cat.

Here is a simple explanation of the A/R ratio:
https://gcg.com.au/component/rsticketspro/view-article/25-turbine-housing-and-a-r-sizing

Trim explained: http://www.dieseladdict.com/turbo-wheel-trim/

and flow requirements specified
http://www.wcengineering.com/articles/compressormaps.html#wce1
.
FYI: Sale here. https://www.turbokits.com/Turbo_Cha...8_T4_.80ar_Twinscroll_IWG_Turbocharger/11455/
.
 

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Integrator
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EFR 6258-G or 6758-G double scroll are great turbos. They have BOV integrated into the housing.
Here are the maps. As you can see, at 2.0 PR, 6258 favors the lower end + has efficiency of 76%. It is good up to 31lb/min.

EFR 6758 favors mid and high end and flows well up to 35lb/min at 2.0 PR; works even better at PR=2.2 ("chipped" cars).

P.S. These are a "real" maps, not a generic approximations.
.
 

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Discussion Starter #12
Thanks again, unfortunately my cars running issues have resurfaced so putting my efforts into that. I've not been able to get freescan to run, although a friend thinks I need to change the port settings. I'm still thinking vacuum issue, I think I've changes them all except the small hard plastic ones to places like the map sensor. I hope to borrow a vacuum tester so hopefully that will help.
 

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Thanks Mr Dangerous I'm educating myself as I go down this path sorry to say much of the technical spec you sent is beyond me at this time. Certainly turbo lag is one of my complaints although it's fun when the power comes on, it reminds me of my 2 stroke motorcycles riding in the powerband many years back. I do get that this might not be the best fit. I was sort of hoping to make it work based on the fact I already have it. If I were to upgrade/repair the old T3 new go ball bearing and Turbine wheel could I expect/notice a performance improvement?

Also if I were to go bigger chargcooler and secondary injectors, billet turbine for the 3071 would that be enough to consider it?


Back in the day John Welch used to rebuild the T3 turbo with ceramic ball bearings and a few other mods that I can’t recall. I believe Mike Reed’s old S4 had the upgraded turbo and really liked it.

Search some old posts in the Yahoo Turbo Esprit forums to get some insight. He’s very knowledgeable and will steer you in the right direction. If it was me... I would contact John first.

Here is his website....

http://www.wcengineering.com

Here is the page regarding the Ceramic Ball bearing Turbo Upgrade Kit....

http://www.wcengineering.com/esprit/turbo.html


Personally... my turbo lag diminished considerably after I did the Ram Air upgrade with a K&N, and installed a HKS SSQV BOV on my S4s.

Dominick


Sent from my iPhone using Tapatalk
 

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Discussion Starter #14
Thanks Yellow Hornet, Turbo goes back on the back burner until I get these other issues now sorted out. I do have the k&N filter and the Red popular BOV already fitted from PO. So I've only driven my car with these mods so can't compare lag before/after.
 

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Back in the day John Welch used to rebuild the T3 turbo with ceramic ball bearings and a few other mods that I can’t recall. I believe Mike Reed’s old S4 had the upgraded turbo and really liked it.
Dom, I have Mike's S4 and the Welch turbo has about 35,000 miles on it. According to John the turbo is good for about 35 to 40K miles before it may be time for a rebuild. Since he no longer builds them I guess I'll be in the market for something new. That's why I've been following the GT turbo threads closely.
 

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Pete- I would assume that if your wheels and housings are OK, any competent vendor could rebuild the center section with a new bearing assembly.
(not to dissuade you from an upgrade if you need an excuse >:)
 

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Dom, I have Mike's S4 and the Welch turbo has about 35,000 miles on it. According to John the turbo is good for about 35 to 40K miles before it may be time for a rebuild. Since he no longer builds them I guess I'll be in the market for something new. That's why I've been following the GT turbo threads closely.


Hey Pete.. it’s been a long time. I totally forgot you have Mike’s S4. Like Snowrx mentioned, maybe you can get the center section rebuilt. Maybe if you can somehow get a hold of John Welch, he can refer you to someone who is familiar with his work.

My old Eagle Talon that was heavily modified (just like a Fast N Furious car) had a turbo modified by this guy Newark. If I can dig up my old paperwork, I’ll reach out to you.

Dominick


Sent from my iPhone using Tapatalk
 

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Thanks Yellow Hornet, Turbo goes back on the back burner until I get these other issues now sorted out. I do have the k&N filter and the Red popular BOV already fitted from PO. So I've only driven my car with these mods so can't compare lag before/after.


Your welcome! Do the ram air conversion when you get a chance.... there was noticeable throttle response and is a great mod with the addition of a K&N and an exhaust.

Here is a link to the instructions....

http://www.lotusespritworld.com/EGuides/EModifications/RamAir_conversion.html

Dom


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Hey Pete.. it’s been a long time. I totally forgot you have Mike’s S4. Like Snowrx mentioned, maybe you can get the center section rebuilt. Maybe if you can somehow get a hold of John Welch, he can refer you to someone who is familiar with his work.

My old Eagle Talon that was heavily modified (just like a Fast N Furious car) had a turbo modified by this guy Newark. If I can dig up my old paperwork, I’ll reach out to you.

Dominick

Sent from my iPhone using Tapatalk
Thanks Dom, I appreciate the help. BTW, you'll be glad to know that I've traversed the Jersey Pike in the Lotus a few times without incident. :smile2:
When I pulled the motor a few years back, the first thing I replaced was that dang intake manifold hose.
 

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Thanks Dom, I appreciate the help. BTW, you'll be glad to know that I've traversed the Jersey Pike in the Lotus a few times without incident. :smile2:

When I pulled the motor a few years back, the first thing I replaced was that dang intake manifold hose.


Your welcome Pete. Glad to hear that my roadside repair job held up all those years without fail . That day was definitely one for the record books. Hope all else is well and it’s great to hear from you.

D


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