Charlie C
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| posted on 5/2/18 at 03:36 PM |
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Haynes Roadster Turbo MX5 engine project
I’ve decided to a turbo to my Haynes Roadster as there’s not a massive amount of information out there about turboing these cars so I thought I would
make some notes on here in case anyone else wants to do likewise.
My car
It’s a Talon chassie with sierra running gear with an MX5 engine, when I started the build there wasn’t Talon mx5 chassis option only the Saturn plans
and I didn’t like the look of the rear diff cage. The car passed the IVA test in January 2017 with a K reg age related plate so no cat which is handy,
so I’ve only run it for one summer effectively. My roadster is a little on the heavy side with a full cage and steel floor and cast engine block but
its going on a diet with a lighter cage and aluminium floor and a few other chassis improvements.
The Engine
The engine is a recon mk1 1.6 mx5 from Basset Down Balancing and I’ve added GSXR ITBs, Piper Cams, lightened flywheel, megaspuirt MS3 and a Westfield
SDV exhaust + manifold (all for sale soon) its been dyno’d at 143bhp which is fun and make a nice sound, but it could do with a little bit more power.
I don’t go on track days I just like a bit of fun on the Worcestershire Herefordshire and Shropshire B roads on my own because id don’t have any
friends.
Plans
I had several plans and these included tuning my 1.6 with some head work and Jenvey ITB’s, adding a supercharger, building a mx5 1.8 engine using a
mk2 head and a mk2.5 bottom end I read this was the best combination or adding a turbo to my 1.6 or the 1.8. my ideal bhp target was about 190-220bhp
and after talking Dale at Bailey Performance, Basset Down Balancing and Nick at Skuzzle they all said the same thing which was to stick with my 1.6
and add a turbo.
Before I go any further I did concider other engines and gearbox’s which would be lighter and probably better but better the devil you know and all
that also I had the engine already set up.
The advice a have been given was to use a TD04 turbo (from the older Subaru’s) but this is where the advice differed, one person said get an old cheap
turbo and if its crap of fails then buy another cheap but don’t buy the Chinese copies, this made sense as there is a lot of old subaru’s out there,
but I don’t like to take that sort of gamble. Other advice was to buy a cheap Chinese copy and when it start burring oil replace it with another this
made some sense as well, but I don’t like replacing bit just because its cheap to do so. The last piece of advice was to buy reconditioned turbo, but
these are about £550-700 I spoke to several companies sell refurbished TD04’s they all said their where the only ones worth buy because we test ours
and balance then bla bla bla which is all probably true but it made me less confident of the refurbished turbos.
I gave up on the TD04 because of the conflicting advice and at some point the supply of TD04’s will start drying up and increase the price when it
need replacing, a used one is already £200 on average which they use to be about £100 a couple of years ago. After some research on mx5/miata web
sites I came up with two turbo options either a Garret GT25 or Borg Warner EFR, although the latter is a beautiful piece of kit at £1550 its outside
my budget so I decided to go with a Garret GT25.
For my 1.6 engine and the space available in the chassis the GT2554r appears to be the most suitable it the smallest Garret GT25 but I’m not after
huge power and space is limited after all. The handing thing about the MK1 1.6 is they have a oil and water supply on the side of the block left over
from when the engine was original designed for a turbo, the most turbo need both so this is very usefull.
For the turbo manifold I’ve found this great company called Dave Fab https://davefab.com/ who make a turbo manifold and down pipe specifically for
Westfield SDV’s but for the TD04 amongst other things. They have redesigned the manifold and down pipe to take the GT2554r turbo in the Haynes
chassie. They are really helpful chaps well worth a call, have a look at the web site there is some really nice work on there.
To be continued…………………
Can someone recommend a photo hosting website so I post some pictures.
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Bunje
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| posted on 5/2/18 at 03:47 PM |
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i did the very same thing as you in my westfield.
i have the 1.6 engine turboed with jenvey throttle bodies. i used the td04 i got mine from ebay for 85quid and it has been fine ever since. they are
ten a penny on the subaru facebook pages and arent hard to get hold of at all infact i have a spare which i got for the same money. its made 196bhp at
wastegate pressure youll probarbly need to uprate your clutch as the 1.6 clutch isnt the best. ive just finished a bottom end refresh with some forged
rods to turn up the boost when i can be bothere to take it and get it mapped again
take alook at https://davefab.com/ for your manifold and downpipe i know someone who has one fro his westfield and its a nice bit of kit unless you
already have all this stuff then ignore me lol
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Bunje
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| posted on 5/2/18 at 03:48 PM |
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also if your looking for some friends lol there are quite a few people around you me myself. im not actually that far away from you in dudley
[Edited on 5/2/18 by Bunje]
[Edited on 5/2/18 by Bunje]
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theduck
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| posted on 5/2/18 at 03:49 PM |
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Good luck with the build. If you need any help or advice give me a shout, I turbo'd my kit and have helped a few others with there turbo
conversions. GT2554 should spool up nice and quick!
As for photohosting try https://imgur.com/
oh and the pries you are quoting on TD04 make me realise how much of a bargain I got! £50 delivered 
[Edited on 5/2/18 by theduck]
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Charlie C
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| posted on 5/2/18 at 04:25 PM |
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Hi
Thanks for the offer of help, I may take you up on that when the oily parts start coming together.
Engine work
The engine is back off to Basset Down Balancing to have forged rods as these are the weak point of the engine and the crank balanced for good measure.
I’ve got a small oil leak at the front which is going to be looked at hopefully I’ve got a leaky seal and nothing worst. I did ask about have the
crank knife edge but was told its not worth it for the kind of bhp and driving I’m doing, If I was racing a high-powered N/A engine it would help I
guess. Also I considered have the sump chopped but it wasn’t worth the extra cost, I had to choose between rods or sump so I thought rods would be a
better investment.
Cams
Currently I have a set of Piper fast road cams but from what I can gather they have too much overlap for a turbo engine. Some research found this
post which to summaries recommends using stock cams and to retard the intake by 6º
to reduce overlap, exhaust stays as stock. Vernier cams and dyno time are what's needed and a good tuner that knows what he's doing.
Clutch/flywheel
The standard 1.6 clutch will struggle with the additional power or so I’ve been told and read in many post so I’ve gone for the Skuzzle lightweight
flywheel and clutch combo which is based on the dimensions of the 1.8 flywheel, it been recommended to me by several people and the price is good, the
fly wheel is 4.85kg which is a lot lighter than the 9.5kg ish standard flywheel, I did read somewhere that the mk2.5 mx5 1.8 fly wheel is lighter than
the other 1.8 wheels I have a mk2 and mk2.5 flywheels and they are exactly the same.
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theduck
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| posted on 5/2/18 at 04:34 PM |
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Using your current cams, but dialing out the overlap buy adjusting the timing of the exhaust and inlet separately may well be an option, gives you
some benefits like the increased lift while being able to reduce overlap back to or near to stock cams level.
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rdodger
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| posted on 5/2/18 at 05:08 PM |
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Sounds like a good plan and that manifold/downpipe looks like a good solution to fit it all in.
I would consider doing a coolant re route while you are about it to aid cooling to cylinder 4.
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Charlie C
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| posted on 5/2/18 at 05:19 PM |
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quote:
Originally posted by theduck
Using your current cams, but dialing out the overlap buy adjusting the timing of the exhaust and inlet separately may well be an option, gives you
some benefits like the increased lift while being able to reduce overlap back to or near to stock cams level.
Hi
I should have said I plan to use the standard cams and dial out the over lap, i think the piper cams have more over lap to dial out.
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Charlie C
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| posted on 5/2/18 at 05:21 PM |
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Hi
I forgot to mention I already have a coolant reroute.
quote:
Originally posted by rdodger
Sounds like a good plan and that manifold/downpipe looks like a good solution to fit it all in.
I would consider doing a coolant re route while you are about it to aid cooling to cylinder 4.
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rdodger
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| posted on 5/2/18 at 05:30 PM |
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quote:
Originally posted by Charlie C
Hi
I forgot to mention I already have a coolant reroute.
quote:
Originally posted by rdodger
Sounds like a good plan and that manifold/downpipe looks like a good solution to fit it all in.
I would consider doing a coolant re route while you are about it to aid cooling to cylinder 4.
Sounds like you are ready for the turbo then
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bart
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| posted on 6/2/18 at 08:42 AM |
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HI
just a hint , pick up a 1.8 mk2 engine and box , much better engine . forged rods as std and can take a fair boost in std form.
you can pick up a mot failure for around £300 . better box , bigger flywheel ( clutch ) better ecu.  oh and the cranks are much better. loads of
info in usa . ps if you get one ill have the steering column of you for a price !
BE ALERT > BRITAIN NEEDS LERTS
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theduck
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| posted on 6/2/18 at 09:02 AM |
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quote:
Originally posted by Charlie C
quote:
Originally posted by theduck
Using your current cams, but dialing out the overlap buy adjusting the timing of the exhaust and inlet separately may well be an option, gives you
some benefits like the increased lift while being able to reduce overlap back to or near to stock cams level.
Hi
I should have said I plan to use the standard cams and dial out the over lap, i think the piper cams have more over lap to dial out.
Shouldnt need to dial out the overlap on the stock cam, some overlap is fine. Depends how much opportunity you have to play with it, I have access to
a dyno for little to no money so for me, I'd give the piper a go first and see what it could do. I reckon setup with overlap dialed back to
somewhere near the stock cam overlap it could be a nice setup!
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Charlie C
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| posted on 6/2/18 at 09:40 AM |
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quote:
Originally posted by bart
HI
just a hint , pick up a 1.8 mk2 engine and box , much better engine . forged rods as std and can take a fair boost in std form.
you can pick up a mot failure for around £300 . better box , bigger flywheel ( clutch ) better ecu. oh and the cranks are much better. loads of
info in usa . ps if you get one ill have the steering column of you for a price !
Hi
You may well be right but that’s the opposite to the opinion of all the advice I've been given so far by quite a few reputable MX5 engine
builders and tuners which is the 1.8 make a terrible turbo engine compared to the 1.6mk1.
I use to totally agree with your opinion to the extent that I purchased a MK2 and MK2.5 engine to build into one with the best parts from both as
detailed later on in the post. I’m now trying to sell both engines which are untouched.
Apparently the 1.8 isn’t built for a turbo but the 1.6 mk1 was originally a turbo engine and retained all the turbo internals.
The 1.8 doesn’t have forged rods as standard and bend at the same point as 1.6 rods. The only difference in MX5 gearboxes is between the 5 speed and
the 6 speed (only a few 1.8 had 6 speeds) and opinion is split between which is the better box I've been told that most mx5 racer prefer the 5
speed.
The flywheels have a larger diameter friction surface which makes life easier for the clutch.
The Mk2 1.8 has basically the same crank as the mk1/2.5 1.8 which are both bigger versions of the 1.6 but the 1.6 and better lubrication, the MK2.5
1.8 has an additional main bearing support.
From chatting with MX5 engine builders and tuners the 1.8 mk2 BP4W head is the best flowing from standard but companies like Blink motorsport get
better flow results from modifying a MK1 head compared to a standard or modified MK2 head.
The MK2.5 block BP6D has the highest compression pistons 10.0.1 and main bearing support plate (MBSP) to add more rigidity to the bottom end. Which
when combined all makes for a good normally aspirated engine but doesn’t perform better then a mk1 1.6 when a turbo is added. This is the opinion of
professional engine builder and tuners and is supported by what I’ve read on the US and UK MX5 forums. I have no direct experience, so I can only go
with the what I feel confident with when parting with cash.
Thats the point and joy of kitcars they are all different and are our interpritations of what we like most in cars, if we all shared the same opinion
we would all drive dull corperate commuting boxes.
Charlie
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Charlie C
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| posted on 6/2/18 at 09:48 AM |
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quote:
Originally posted by theduck
quote:
Originally posted by Charlie C
quote:
Originally posted by theduck
Using your current cams, but dialing out the overlap buy adjusting the timing of the exhaust and inlet separately may well be an option, gives you
some benefits like the increased lift while being able to reduce overlap back to or near to stock cams level.
Hi
I should have said I plan to use the standard cams and dial out the over lap, i think the piper cams have more over lap to dial out.
Shouldnt need to dial out the overlap on the stock cam, some overlap is fine. Depends how much opportunity you have to play with it, I have access to
a dyno for little to no money so for me, I'd give the piper a go first and see what it could do. I reckon setup with overlap dialed back to
somewhere near the stock cam overlap it could be a nice setup!
You make a good point I'm a bit new to working cams how do you calculate overlap?
I read somewhere that you take the timing figures for example the Piper
Cams have 9‑49 58‑18 and you add the first and last figures togther which make 27degress of over lap, does that sound
right?
Charlie
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theduck
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| posted on 6/2/18 at 09:54 AM |
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Yep thats it, Piper have a really helpful page on this actually
quote:
Overlap: The number of crankshaft degrees were both the inlet and exhaust valve are open at the same time. To calculate overlap: Add the
opening number of the inlet cam to the closing number of the exhaust cam, ie the first and last numbers of the cam timing. Using our same example of
the 23/67 inlet and 67/23 exhaust (usually referred to as 23/67 - 67/23), add together the first and last numbers (23 and 23) and the total (46) is
the overlap. In general terms the larger this number or the greater the overlap, the hotter the cam
http://www.pipercams.co.uk/pipercams/www/tech.php
Stock MX5 cam is about 20* so you wouldnt need to dial much out to get back to a stock amount of overlap. I'd definitely be giving that a go!
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Charlie C
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| posted on 6/2/18 at 10:04 AM |
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Hi
The list of parts so far is;
Spark plugs = NGK6097 / BKR7E
Injectors = RX8 Yellow - Got
Intercooler
Oil cooler = Mocal
Air box with cold air feed.
Turbo = GT2554r - Got
Turbo oil feed + water supply
Inlet manifold and TB = standard MX5 1.6 -Got
Exhaust manifold and down pipe = Dave Fab – on order
Exhaust + silencer = stainless 3”
1.8 lightweight flywheel and clutch = Skuzzle – on order
Boost control solenoid = VAG N75 from fleebay
Dump/recirculating value = second hand Forge from fleebay
Intercooling pipe work and sundries.
I'm sure there will be a few more bit but that should cover most of it.
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Charlie C
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| posted on 6/2/18 at 10:45 AM |
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quote:
Originally posted by theduck
Yep thats it, Piper have a really helpful page on this actually
quote:
Overlap: The number of crankshaft degrees were both the inlet and exhaust valve are open at the same time. To calculate overlap: Add the
opening number of the inlet cam to the closing number of the exhaust cam, ie the first and last numbers of the cam timing. Using our same example of
the 23/67 inlet and 67/23 exhaust (usually referred to as 23/67 - 67/23), add together the first and last numbers (23 and 23) and the total (46) is
the overlap. In general terms the larger this number or the greater the overlap, the hotter the cam
http://www.pipercams.co.uk/pipercams/www/tech.php
Stock MX5 cam is about 20* so you wouldnt need to dial much out to get back to a stock amount of overlap. I'd definitely be giving that a go!
Stock 1989-93 Intake 5 BTDC 51 ABDC Exhaust 53 BBDC 15 ATDC Valve Timing 20 deg overlap
1988-89 GTX (turbo) Intake 5 BTDC 51 ABDC Exhaust 69 BBDC 1 ATDC Valve Timing 6 deg overlap
Piper cam Intake 9 BTDC 49 ABDC Exhaust 58 BBDC 18 ATDC Valve Timing 27 deg overlap
The 1988-89 323 GTX turbo is the same 1.6 engine as the mx5 mk1 1.6 which has 6 deg overlap.
To get to stock overlap the piper cams need adjusting as follows
Intake advance (clockwise) 4 degrees / Exhaust advance (clockwise) 3 degrees
To get to GTX overlap the piper cams need adjusting as follows
Intake advance (clockwise) 4 degrees / Exhaust advance (clockwise) 17 degrees.
I’m a complete novice at this and the information on mx5 forums is starting to hurt my head, any help would be great thanks
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theduck
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| posted on 6/2/18 at 11:01 AM |
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It can get overwhelming very quickly. I can see what they are saying about the gtx cam, but I dont think its necessary to go that extreme, I'm
sure it drives well, but so do all the mx5 turbos running stock cams at stock timing.
Who is doing the tuning for you? Id maybe discuss with them what you want to achieve in terms of how the car drives etc and see what they suggest.
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Charlie C
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| posted on 6/2/18 at 11:18 AM |
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Hi
I'm planning on using Dale at Bailey Performance, he set my megaspuirt up and has been really helpful.
You make a good point about all the MX5 turbos out there on standard cams.
Thanks
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theduck
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| posted on 6/2/18 at 11:20 AM |
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Dale is brilliant, should be able to give you some sensible advice on what you want to achieve.
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Charlie C
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| posted on 6/2/18 at 11:35 AM |
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Some picture of the nice new turbo
https://imgur.com/98kGmsE
https://imgur.com/cyAy2IM
https://imgur.com/Ndk1QvV
[Edited on 6/2/18 by Charlie C]
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Charlie C
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| posted on 7/2/18 at 10:21 AM |
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Hi
I should be removing a few parts this weekend and putting them up for sale if anyone interested?
1, ITB's GSXR throttle bodies with Danst manifold + Pipercross 600 Series Sealed Airbox + back plate and trumpets
2, Westfield SDV exhuest manifold and silencer
3, 1.6 lightend fly wheel from Basset Down Balencing including the clutch which has only cover 500 miles.
[Edited on 7/2/18 by Charlie C]
[Edited on 7/2/18 by Charlie C]
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Charlie C
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| posted on 12/2/18 at 08:20 AM |
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Hi
I took the engine out yesterday read to take to Basset Down Balancing to have forged rods installed and bottom end balanced.
I found what appears to be the rocker cover gasket leaking oil at the back and front, I knew oil was leaking but I thought it was the crank front oil
seal so should be an easy fix.
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Charlie C
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| posted on 15/3/18 at 10:05 AM |
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I've been busy stripping the car and cutting of the steel floor ready for an ali floor, before and after photos its depressing to see it in its
current state.
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Charlie C
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| posted on 15/3/18 at 10:11 AM |
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Loads more to do, I'm also tiedying up the front end new N/S front diaginal the current arrangment was to accomodate the westfield SDV
manifold.
once I have the turbo manifold and down pipe and can put my spare engine and gear box in and start working out where everything can fit or be made
neater than before.
Cut the welded in floor out has been a right pain I've gone through about 20 1mm cutting disc so far.
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