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1985 Mayfair. 998 Na To Turbo Conversion.

roundnose

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#1 #Tried It 2

#Tried It 2

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Posted 06 January 2017 - 03:48 PM

Hello guys and girls.

 

Having owned a my 1985 Mayfair for many years i had tuned it quite heavily as a naturally aspirated car. It was fitted with a Calver RE13OT cam, lightened Verto set up, 3.44 final drive, HIF44 and heavily modified 998 head, alongside the exhaust and other mods producing over 70 BHP it was a a very fun revvy lump. Rather deceptive with its standard interior, patchy blue paint and lumpy exhaust note. Fooling many into believing shes nothing but an out of tune mini with a loud exhaust. Hence the missus naming the car #Tried it 

 

However, rather sadly, it decided to chew a bearing, just 2 days after starting for the first time after an overbore to +100 thou and a head skim to bring the compression to 11:1. 

 

So as i rather frustratingly took apart the freshly rebuilt engine. I decided that i would take the massive jump of going not only from NA to turbo but also to undertake a conversion from carburettor to sequential and staged fuel injection and separate coils using mega squirt MSX3 ECU.

 

My initial intention was to reuse as much of the NA engine as possible but after loads of researching and reading, i have take the decision to break and sell the NA engine. This is all listed on turbo mini forum ( http://www.turbomini...p=vt&tid=605311 ), please take a gander as none of the parts are of use to me any more but may be of use to you. And start again with a unmodified 998 A+.

 

So i hit ebay for a scrappy engine, ended up buying 3 in a job lot. They arrive this Monday, hopefully at least one will be in good condition. So i can begin this journey to torque steer and frustrating tiny problems holding me up at every step. Built enough engine not to know that if it can go wrong it will.  

 

I have been buying and collecting parts for this conversion over the last few months but am a long way of every thing. 

 

My intended finished spec is as follows:

 

998 A+ block bored out to +60 thou. Opened up water ways around the pump and the two large coolant holes at the clutch end. Apart from the coolant the 3 coolant holes closest to the clutch, the rest will be tapped and blocked with grub screws. Creating coolant flow similar to that of a dry deck. 

 

Omega Forged 998 +60 pistons.

 

Standard 998 conrods and crank. Though these along with all of the bottom end will be dynamically balanced. 

 

MED light weight Verto fly wheel fitted with the AP rally friction plate and and RTS spring plate. Following the guide on Turbo Mini forum.

 

The cylinder head i will be modifying/grinding myself from a standard casting. Based on my NA head ports and the yellow bibles guide to modifying the chambers. I will be aiming for a 9:1 CR to give me off boost drive ability while maintaining the ability to run a good quantity of boost. i would like at least 14 psi which theoretically should give me around 140 BHP. I will be using a Payen copper head gasket to begin with which will hopefully hod it together.

 

My turbo of choice is an IHI VL38, removed from a Fiat 500 Abarth. according to Fiat it was a 2012 car. i have read that it can produce up to 20 PSI before it becomes inefficient. It will be mounted above the clutch housing using an equal length 3 to 1 manifold, with sample tubes for the lambda sensors. the inlet manifold mill also have to be made to support the port injection, the selection of throttle body is undecided, as i will also need a idle control motor so a 50 mm butterfly with a built in idle motor would be perfect.

 

The intercooler is planned to be a one off to fill as much of the space behind the grill without having to alter or remove the grill. Have to keep it as incognito as possible :P, and naturally a Forge Motorsport recirculating valve haha.

 

The gear box is a standard unit fitted with a central pick up, windage tray and a 3.2 final drive.

 

i am planning to use a 2 core super cool, fitted in the standard location, mechanical fan removed and electric fan fitted to the wing side of the radiator. i will also be removing the mechanical water pump and replace it with a Davis Craig 80 L unit fitted to the subframe. The alternator will be dropped to sitting between the block and the sub frame and utilise a short belt. The Alternator is a 60 AMP  unit from a Suzuki swift. with the extra space generated i will attempt to build ducting to the radiator. i am also intending to use a full bypass thermostat, to try and ensure the most effective coolant flow possible.

 

i intend to run the to and from fuel lines through the car using Teflon braided lines. 

 

there are a few other bits and pieces but it should be a rather comprehensive build. i will have to take a bunch of photos of my growing collection of parts and of course the build once it gets going :)

 

cheers 

 

#Tried It 2


Edited by #Tried It 2, 11 January 2017 - 11:04 AM.


#2 daveb99

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Posted 21 May 2017 - 12:41 PM

Sounds well thought out! Have you made any progress with it?

#3 #Tried It 2

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Posted 24 June 2017 - 01:21 PM

So I think it is time for an update. There has been some changes and lots of ups and downs but slowly making positive progress.

 

Originally I intended to just turbo and inject a 998. However, the project has some what spiraled taking lots of twists and turns. 

 

Once my scrap engines arrived, I went to town stripping them apart. They really were scrap engines, bores filled with water covered in ancient grease and moss, truly grim. So I salvaged what I could and managed to source a more suitable starting point.

 

I took the decision to polish the interior of the block, removing all of the cast lines and roughness to encourage oil drain back. I also took the decision to polish the conrods, to help to remove potential stress points. After a couple of trial runs I started to realise just how long the process would take. 

It was at this point that I sold my old +100 thou block. When the buyer came to collect the block he got chatting to my misses. Luckily she had been paying attention to my complaining about polishing and wishing that someone made forged 998cc conrods for a reasonable price. The buyer suggested that I should get in contact with a man called Rob Selby at Selby Engineering. He produces forged 998cc conrods alongside many other interesting and well engineered parts. 

 

So the decision was made to step away from standard rods to the forged 998 rods, a super finished crank and have Rob conduct the machining on the block for the +60 pistons, cam bearing, line honing and the like. So I left my parts with Rob and got on with the wait. Few weeks floated by, and I had to return to uni so a few more weeks past by. After completing my final block of assignments I decided to chase up my parts. It was at this point that I discovered the very sad news that Rob had past away, after a long and courageous battle with cancer. Taking his experience, knowledge, skill and enthusiasm with him, a loss to the mini and engineering world. 

 

When I met Rob, he had shown me around his workshop, and we spent a few hours talking about my engine, his engines, parts and some of his brilliant stories. One of these stories led to him telling me about a series of 6 forged steel conrods and crankshafts that he had designed and had manufactured for the mini 7 Series. However politics and the like led to the design being band. 

 

So this is where it gets interesting. With Robs sad passing some of his parts had become scarce, such as the crank. So through negotiation with Robs son Lewis, i was put in contact with one of the owners of the crank and rod sets. So by luck I have now been able to acquire a set of forged rods and a forged crank to fit my engine :). I would have never been able to afford these new, so it is quite a turn of events. The only problem being that the gudgeon pin diameter on the rods is 18mm, where as on the standard rods it is 16mm. So my already purchased omega +60 pistons are now redundant. So to ebay it is for them. The pistons that will fit the rods were designed by Rob himself, and as far as I am aware give me exactly 1 litre. They are forged, so will give me an entirely forged bottom end. However the pistons are on order so I just have to wait.

 

The fully forged bottom end, has changed the end goal. From just turboing and injecting, to seeing just how much you can produce from a 1 litre engine. Its become quite an exciting prospect. I will have to get some pictures up on here of the crank and rods, as they are true engineering porn. They are beautiful.

 

The choice of cylinder head has also changed. My original intention was to use a standard A+ casting. This has now changed to a 12G202, due to the larger ports and potential for comprehensive modification of the chambers, without blowing through to the jacket. The plan is to move the valve stems wider apart to enable the fitting of larger 1275 valves to the casting. I am also intending to fit an extra stud at either end of the cylinder head, to help to hold all the boost in :). The head gasket has also evolved from a copper gasket, towards a multi layered steel option.

 

The VL38 has been rebuilt and modified by Turbo Technics, being fitted with a larger billet compressor wheel. According to technics, on the fiats they have produced 200bhp, so it will be interesting to see how it works on the mini. I have also managed to source a suitable throttle body in the rover 1.8T Kseries unit. 48mm, with a single take off for the idle stepper motor :). I chose the webcom stand alone idle motor as it should work well with the ECU.

 

Got hold of a NOS Rover thermostat housing from XL Motorspares in New Malden, just down from Krispy Kremes. Graham, the owner, has a massive collection of 80's and 90's parts. Lots of hard to find bits which is cool. Well worth a call, if you cant find a part.  

 

As I am intending to use the MSX3 ECU, giving me sequential injection and spark. I will need both a crank and cam signal input. Having spent a longtime looking at the designs that others who have converted to MSX3 have used, and the commercially available designs for the GM V8 engines in the US. And will be modifying a distributor to act as my cam sensor, I intend to document this conversion (and whether it works) to help others undertaking the same conversion.

 

I will get some pictures up in the near future, as no feed is complete without pictures :).

 

Any comments or suggestions are welcome.

 

#Tried It 2



#4 #Tried It 2

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Posted 26 June 2017 - 11:59 AM

I have uploaded lots of pics on to my Turbo mini forum feed. The feed is titled: 998cc NA Carb to Turbo EFI (Building a sleeper with the potential to make big Power).

 

http://www.turbomini...p=vt&tid=609046

 

Please have a look, and comment.

 

Regards 

 

#Tried It 2



#5 daveb99

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Posted 29 June 2017 - 09:40 PM

Will be interesting to see this build pan out, sounds like you had some good luck with all them forged bits!





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