TVR Chimaera Turbo - Build Thread
Discussion
I am copying this over from another forum so hopefully everything works ok and sort of makes sense 
The original thread began in December 2015. Here goes:
Thought I would post this up on here as its always good to get constructive feedback and ideas from others, and i guess some people might find it interesting
I have had my 4.0 Chimaera for a while now. It has 115,000 miles on the clock and is making around 220bhp. The car is very well sorted with a fresh chassis, upgraded Cosworth front brakes, polybushes all round and Gaz Gold coilovers. It just needs a bit more power
Last year i converted it to run Megasquirt fuel and ignition so engine management wise I am sorted, will just need bigger injectors.
I did dabble with the idea of getting shot and buying a Cerbera or Tuscan but I have had the little Chim over 6 years now and I know I would regret selling it, hence the current plan!
Over the winter I will be fitting it with a single turbo, and getting the engine fully rebuilt with big valve heads but otherwise standard. The aim is to get around 400bhp at 12psi which I am sure will be plenty in a 1050kg car. I'm sure plans will evolve and extra bits will be done but I will document it all here.
Anyways enough blabbing. Here is the car when we drove it to Norway a few years ago:
And at Snetterton in November:
This turned up a couple of days ago. It only just fits in the engine bay and I have ordered up the pipework to make the new manifold, but I doubt it will get here before Christmas. I was planning on modifying the Decat y-piece I already have in there but I think it will end up better if i just make one from scratch (not that I have ever done it before!). The turbo is a Holset HX35 copy with a water cooled core, made and balanced in England with parts sourced from the UK and USA. It has a standard T3 flange so if i feel the need to upgrade to a Garrett in the future it will be an easy swap.
The original thread began in December 2015. Here goes:
Thought I would post this up on here as its always good to get constructive feedback and ideas from others, and i guess some people might find it interesting
I have had my 4.0 Chimaera for a while now. It has 115,000 miles on the clock and is making around 220bhp. The car is very well sorted with a fresh chassis, upgraded Cosworth front brakes, polybushes all round and Gaz Gold coilovers. It just needs a bit more power
Last year i converted it to run Megasquirt fuel and ignition so engine management wise I am sorted, will just need bigger injectors.I did dabble with the idea of getting shot and buying a Cerbera or Tuscan but I have had the little Chim over 6 years now and I know I would regret selling it, hence the current plan!
Over the winter I will be fitting it with a single turbo, and getting the engine fully rebuilt with big valve heads but otherwise standard. The aim is to get around 400bhp at 12psi which I am sure will be plenty in a 1050kg car. I'm sure plans will evolve and extra bits will be done but I will document it all here.
Anyways enough blabbing. Here is the car when we drove it to Norway a few years ago:
And at Snetterton in November:
This turned up a couple of days ago. It only just fits in the engine bay and I have ordered up the pipework to make the new manifold, but I doubt it will get here before Christmas. I was planning on modifying the Decat y-piece I already have in there but I think it will end up better if i just make one from scratch (not that I have ever done it before!). The turbo is a Holset HX35 copy with a water cooled core, made and balanced in England with parts sourced from the UK and USA. It has a standard T3 flange so if i feel the need to upgrade to a Garrett in the future it will be an easy swap.
Edited by AceOfHearts on Tuesday 19th September 22:31
Edited by AceOfHearts on Tuesday 19th September 22:31
Edited by AceOfHearts on Tuesday 19th September 22:31
I started cracking on with the work today. So lets start with some before photos
So I started by pulling out the Clive F y-piece. Thankfully I was able to do it without dropping the exhaust.
And then I encountered my first problem. The flanges I bought have different sized recesses than what i need, so I walked them down to my local engineering shop who are going to open them up to the correct size (I will be picking them up tomorrow)
I then placed the turbo in its rough spot and encountered issue number two. Its huge!
I pulled out the removable black cross member and moved the swirl pot out of the way. This meant i could sit it on a small gag of gravel to get it at roughly the right height and eye up my options. I think I am going to have some issues getting it to fit. As you can see here the exhaust port it already off centre and the compressor housing is resting on the two fixed chassis bars. I can lift it into a better position with clearance but it is still very tight. At this point it was getting dark though so I packed up and will carry on tomorrow (and hopefully get some welding done)
I can see why the kits come with the small GT35 copies
So I started by pulling out the Clive F y-piece. Thankfully I was able to do it without dropping the exhaust.
And then I encountered my first problem. The flanges I bought have different sized recesses than what i need, so I walked them down to my local engineering shop who are going to open them up to the correct size (I will be picking them up tomorrow)
I then placed the turbo in its rough spot and encountered issue number two. Its huge!
I pulled out the removable black cross member and moved the swirl pot out of the way. This meant i could sit it on a small gag of gravel to get it at roughly the right height and eye up my options. I think I am going to have some issues getting it to fit. As you can see here the exhaust port it already off centre and the compressor housing is resting on the two fixed chassis bars. I can lift it into a better position with clearance but it is still very tight. At this point it was getting dark though so I packed up and will carry on tomorrow (and hopefully get some welding done)
I can see why the kits come with the small GT35 copies
I got the flanges back from the machine shop today so I could start mocking everything up properly.
I tacked on the 4" to 3" reducers and clamped them onto the manifolds:
I then put the turbo back in place resting on some sandwich bags full of gravel. I sat it a bit higher up in the bay which gave better clearance and looks like it should be workable.
I finished the day by taking some rough cuts from the T-piece. I could really do with a band saw but will have to make do with a grinder. I will just have to go slow and steady with the final finishing cuts.
I tacked on the 4" to 3" reducers and clamped them onto the manifolds:
I then put the turbo back in place resting on some sandwich bags full of gravel. I sat it a bit higher up in the bay which gave better clearance and looks like it should be workable.
I finished the day by taking some rough cuts from the T-piece. I could really do with a band saw but will have to make do with a grinder. I will just have to go slow and steady with the final finishing cuts.
After a bit of research I don't trust those ebay wastegates so will probably end up with a Precision PW46. Am doing a bit more reading before any purchasing though.
In other news I have ordered up a load more pipework today and my intercooler. Had to go 10cm smaller in the end than what I originally wanted due to space, but is still bigger than the kit supplied ones. I have gone for top mounted inlet and outlet to simplify the pipework runs and should hopefully look pretty good
Intercooler turned up today from Rally Design
In other news I have ordered up a load more pipework today and my intercooler. Had to go 10cm smaller in the end than what I originally wanted due to space, but is still bigger than the kit supplied ones. I have gone for top mounted inlet and outlet to simplify the pipework runs and should hopefully look pretty good
Intercooler turned up today from Rally Design
More parts turned up, and I have just ordered my wastegate. I was going to hopefully get the exhaust finished up today but the weather is against me 
I got the top half almost finished the other day though, just need to finish tacking and then can take it off for seam welding. The pipework fit if i'm honest is not as good as I was hoping but its the first time I have done anything like this and i'm sure the welding will take up the slack.
I got the top half almost finished the other day though, just need to finish tacking and then can take it off for seam welding. The pipework fit if i'm honest is not as good as I was hoping but its the first time I have done anything like this and i'm sure the welding will take up the slack.
Small amount of progress so far this week.
I got the upper part of the manifold fully tacked and bolted the turbo up ready for the outfeed pipework to be made. I also removed the main exhaust and welded in a new wideband bung as it was in the old y-piece before which is obviously no longer being used. Was very windy so I used flux cored welding wire but it was a bit messy (thats my excuse anyway)
So all that is left to do is connect these two up and get the wastegate sorted and its off for welding.
MOT is due in Feb as well so I will throw the cat back in for that whilst the welding is getting done and carry on after
I got the upper part of the manifold fully tacked and bolted the turbo up ready for the outfeed pipework to be made. I also removed the main exhaust and welded in a new wideband bung as it was in the old y-piece before which is obviously no longer being used. Was very windy so I used flux cored welding wire but it was a bit messy (thats my excuse anyway
)
So all that is left to do is connect these two up and get the wastegate sorted and its off for welding.
MOT is due in Feb as well so I will throw the cat back in for that whilst the welding is getting done and carry on after
Progress!
New injectors fitted last week (450cc from Astra VXR). The Megasquirt was great, the new injectors are almost exactly twice the flow rate of the old ones, so I just halved the required fuel setting and she drives great!
Now the Trabant is of the drive I could bring the TVR round and start taking it apart. I pretty much stripped all of the cooling system and took the bonnet off for better access. The biggest worry was that the manifold welding had warped the pipework but I am pleased to report it still fits!
With the turbo mocked up in place the plan for the next couple of weeks is get the wastegate mounted, sort out the oil and coolant lines and get the intercooler in and all the pipework sorted. A modified cross member will also need to be made up at the same time. Once that is all good it will come out again for a final clean up / paint / polish and to get the internal wastegate of the turbo welded up.
I have already found an issue with my original plan in that to get any pipework to the turbo inlet is going to be far too restrictive, so I am having to compromise and fit a filter directly to the turbo.
New injectors fitted last week (450cc from Astra VXR). The Megasquirt was great, the new injectors are almost exactly twice the flow rate of the old ones, so I just halved the required fuel setting and she drives great!
Now the Trabant is of the drive I could bring the TVR round and start taking it apart. I pretty much stripped all of the cooling system and took the bonnet off for better access. The biggest worry was that the manifold welding had warped the pipework but I am pleased to report it still fits!
With the turbo mocked up in place the plan for the next couple of weeks is get the wastegate mounted, sort out the oil and coolant lines and get the intercooler in and all the pipework sorted. A modified cross member will also need to be made up at the same time. Once that is all good it will come out again for a final clean up / paint / polish and to get the internal wastegate of the turbo welded up.
I have already found an issue with my original plan in that to get any pipework to the turbo inlet is going to be far too restrictive, so I am having to compromise and fit a filter directly to the turbo.
New oil pressure sender
Oil return sorted, just need another 90 degree fitting for the turbo side. Its a long run but the turbo sits about 5" higher than the sump fitting so hopefully it should drain ok.
Oil feed sorted, hose is way to long though so will pop to the local hydraulics place to try and get it shortened.
Oil return sorted, just need another 90 degree fitting for the turbo side. Its a long run but the turbo sits about 5" higher than the sump fitting so hopefully it should drain ok.
Oil feed sorted, hose is way to long though so will pop to the local hydraulics place to try and get it shortened.
And to finish the day I cleaned and refitted the washer bottle, and relocated the horn. Happy now that everything in the front of the car is sorted
Next up is research for the turbo water cooling. Annoyingly I don't know what thread size they are but should be something standard. Need to decide where to take off from the cooling system too.
One vote so far for bonnet screamer then
Next up is research for the turbo water cooling. Annoyingly I don't know what thread size they are but should be something standard. Need to decide where to take off from the cooling system too.
One vote so far for bonnet screamer then
Made a bit more progress today. My week off is running out quick though and it is frustrating waiting for parts
Finished off the oil return pipe
Drilled and tapped the plenum for MAP sensor / boost gauge takeoff
Fed the pipe through an expertly driller hole in the bulkhead
And teed behind the dash to feed the ECU and boost gauge sensor
I also wired up the boost gauge so it is all ready for the new dash to turn up
On top of all this I also replaced the engine bay flexible fuel hoses with Gates Barricade fuel hose (£30 a meter!), as the R9 hose that I put in 18 months ago had already started to deteriorate.
Drivers seat also removed for bolster repair at the same time. Quite a busy day and a lot of small jobs done
Finished off the oil return pipe
Drilled and tapped the plenum for MAP sensor / boost gauge takeoff
Fed the pipe through an expertly driller hole in the bulkhead
And teed behind the dash to feed the ECU and boost gauge sensor
I also wired up the boost gauge so it is all ready for the new dash to turn up
On top of all this I also replaced the engine bay flexible fuel hoses with Gates Barricade fuel hose (£30 a meter!), as the R9 hose that I put in 18 months ago had already started to deteriorate.
Drivers seat also removed for bolster repair at the same time. Quite a busy day and a lot of small jobs done
Big progress today. I might put a picture up on Pistonheads for a bit of controversy, as I am sure it will divide opinion.
I started by removing the bonnet supports as they were fouling the intercooler pipework. The bonnet is still rigid without them so an easy win.
Before:
After:
I also got the blanking plugs through for the original breather ports on the plenum
Boost controller (now relocated to the other side of the rad for clearance as you will see in the later pics
Now onto the big stuff! Wastegate pipework made up and tacked on
Looking loud 8)
Butt clenching time
Phew
Still lots to do but it has been a good day
I started by removing the bonnet supports as they were fouling the intercooler pipework. The bonnet is still rigid without them so an easy win.
Before:
After:
I also got the blanking plugs through for the original breather ports on the plenum
Boost controller (now relocated to the other side of the rad for clearance as you will see in the later pics
Now onto the big stuff! Wastegate pipework made up and tacked on
Looking loud 8)
- not* a TVR's best friend
Butt clenching time
Phew
Still lots to do but it has been a good day
A bit earlier than planned but another update
The welding is now done. Wastegate takeoff, screamer pipe and the internal wastegate on the turbo. Very happy with the wastegate welding as it is cast iron to stainless and apparently is very easy to crack, but thankfully my friendly tig welder did a great job!
I also turned up a little bung today which allows me to fit the air temperature sensor in the silicone t-piece by the plenum. When the car was NA it was fitted in the front of the car by the air intake, as in the engine bay it suffered from heat soak. I am hoping that by mounting it in nylon / silicone it will insulate it from the external heat, only time will tell though. If it is still not great I will fit it in the front of the car in the cold side of the intercooler (a common solution for turbo MX5 apparently)
The welding is now done. Wastegate takeoff, screamer pipe and the internal wastegate on the turbo. Very happy with the wastegate welding as it is cast iron to stainless and apparently is very easy to crack, but thankfully my friendly tig welder did a great job!
I also turned up a little bung today which allows me to fit the air temperature sensor in the silicone t-piece by the plenum. When the car was NA it was fitted in the front of the car by the air intake, as in the engine bay it suffered from heat soak. I am hoping that by mounting it in nylon / silicone it will insulate it from the external heat, only time will tell though. If it is still not great I will fit it in the front of the car in the cold side of the intercooler (a common solution for turbo MX5 apparently)
Another day, another update.
Here is the air temp sensor in its new home and hopefully protected from the heat
Welded an 8mm barb into the coolant 'swan neck' for the turbo
And a quick lick of paint (still a bit wet in the picture) but shows the modified pipe. If all works well I will get a nice stainless one made up in the future.
I also tidied the wiring in the engine bay and started getting everything ready for its final fit. Not long to go now with only the new cross member needing to be fabricated, the new McLeod clutch to be fitted and the new dash.
Getting dangerously close to its first start!
Here is the air temp sensor in its new home and hopefully protected from the heat
Welded an 8mm barb into the coolant 'swan neck' for the turbo
And a quick lick of paint (still a bit wet in the picture) but shows the modified pipe. If all works well I will get a nice stainless one made up in the future.
I also tidied the wiring in the engine bay and started getting everything ready for its final fit. Not long to go now with only the new cross member needing to be fabricated, the new McLeod clutch to be fitted and the new dash.
Getting dangerously close to its first start!
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