Soliciting thoughts & opinions - power upgrades to a 998

[94touring]

Couple different ways to do it. Russell and maybe Calvert sell some very oversized pistons to make a 1225cc or thereabouts.  Otherwise maybe there are specific height pin small bore pistons to make it work out for 0 deck height and the gasket for proper quench and piston to head clearance without machine work or specific rods.  We'd have to research it a bit.  All a 1098 is really is a stroked 998.  The Russell pistons are just one avenue to take a small bore and basically turn it into a large bore.  It would be a really nice motor.   

[MPlayle]

I had found that VMAXSCART was still around and making their A-Series supercharger kit.  I have been researching both as I had more/less decided after my talk with MiniDave to go with some form of "forced induction".

I am actually leaning more towrds the Turbo kit as it was designed by Jet Motors (US based, so more convenient support) who have sold a significant number of the kits and their kits are also being sold by some of the UK Mini parts suppliers.

I have spoken extensively this week with Jeremy about his kit and compatibility with my current engine specs.  I am likely to order the kit later this week.  I already ordered the parts to sort the drop-gear issue from Mini Spares and will in fact be changing from the current square-cut 1.04xx ratio set to the "economy" 0.958 ratio set - resulting in something closer to a 2.95 final.

[94touring]

He estimate what power it will make?

[MPlayle]

I have not heard from Stuart at VMAXSCART with numbers for the supercharger route.  Jereemy at Jet Motors indicated I should see about double my current hp and torque figures with 8-10 lbs of boost with the turbo kit.  Based on the conversations with Dave as well as Jeremy, that would mean between 80-90 for hp and 90-100 for torque (based on 39 hp and 52 lbft for a stock 998 and allowing for a bit more with my current head configuration).

Granted, those may be "optimistic" numbers.  If reality is more like 60-70 hp and 70-80 lbft, then I will have the power gains to easily support the results of the gearing change.

I plan to add a boost/afr gauge for tuning.

[MiniDave]

Good idea on the AFR gauge.

I'm excited to see you do this, it will be the first turbo installation in our little group. However, I thought the point of going with the turbo was not having to pull the motor?

[cstudep]

Cool, sounds like you have a plan. I have always been intrigued by the turbo kits and it's surely got to be the easiest route to go for what you want to do.

[MPlayle]

Dave,

To solve the gearing issue caused by the non-standard drop gears, I knew I would be pulling the motor to either change the final drive again or change the drop gears.  I did not want to dig into the block itself.  I decided to go with changing the drop gears and the turbo kit for the power boosts.

[skmini]

Following.

[MPlayle]

I will start another thread in the Maintenance/Modifications category when I get started on the project.  Right now, I am collecting the necessary parts for the power upgrade and a couple other details.

[MPlayle]

Here is the start of the new thread mentioned in the "Soliciting Thoughs & Opinions" thread.  Old thread from Lounge

I have started collecting the parts I think will be needed, along with a few spares.

I got in a new set of drop gears from Mini Spares - their EVO series square cut in the selections for an "economy" ratio of about 0.9 versus the 1.04xx I currently have.  I also ordered a new input bearing, since I have to change the input gear.  I also got a couple of clutch oil seals, housing gaskets, and manifolds gaskets.  I am getting the Jet Motors Turbo kit with the complete intake, carb, fuel pump, and fuel pressure regulator.  I am also getting their dual boost/AFR gauge and mounting pod.  I found on ebay a vented rocker cover for the A-Series from a Morris Minor that I can refurbish to have extra venting as recommended.  I am also going to upgrade my ignition coil to a "Flamethrower II".  I can stay with my current distributor since I already upgraded it with an Accuspark module.

The plan is to start the project in November - after the area "car show season".  While doing the performance upgrades, I will also be installing the exterior wood kit as used on some of the Mini Estates from the 1960s.

I will try to post more with pictures as the whole project progresses.

[MPlayle]

New thread in the "Maintenance and Modifications" group is here:

Turbocharging thread

[MiniDave]

I'm excited to see the turbo kit go on, post up lots of pics, please!

BTW, those straight cut drop gears are NOISY! That's why stock ones are helical...

[skmini]

Following.   

[94touring]

What will you be using to create a timing map?

[MPlayle]

No ECU to map.

I will be using my existing 59D4 distributor with the Accuspark module instead of points.

Per Jeremy, the timing should be set for about 18* advance (BTDC) at 4K rpm with the vacuum advance disconnected.

I plan to obtain a new timing light with advance feature and check my current timing at that setting to compare.  I currently have a non-advance timing light that I used to set the current timing at 8* BTDC at 1500rpm per the Haynes manual.

[MiniDave]

Wow, 18* is not much......stock Minis are more like 32-34* at 4K....

[94touring]

Yes so don't do that.  Get with the times and run proper timing. His suggestion is straight out of the 80s.  Spend the money on a 123BT, the blue tooth version that is programmable. I can make you a map in about 2 minutes that will give you vacuum advance, regular timing outside of boost, and vacuum retard in boost. 

[94touring]

Here is a very quick example of a boost map I created based off my bus mapping. type 1 and A series are pretty closely curved with the exception of the vacuum signals and subsequent entry points for vacuum advance.

[94touring]

As a bonus you get a cool dashboard.  Everything is monitored and tuned with your phone. 

[94touring]

Also just looking at his kit, it doesn't come with an intercooler. This is another important factor you must consider. You can either drive in boost as needed, but never too long on hot days, or add a way to cool the intake charge.

[94touring]

Coincidentally I needed to top off my boost fluid in the rx7 just now after taking it for a spirited drive.  You should either install an intercooler or adapt h20 or h20/meth (-20 is 67/33% mixture) to spray into the turbo.  I can show you how this is easily done. I've since converted to oil burner nozzles and made my own adapters for my bus type 1 motor.  Better atomization, great filters, and a clog free design. I'm building an NA race motor for it that will run on pump gas as a result.  The rx7 gets 25psi on pump gas.  Normally limited to 15psi with pump gas but the h20 makes that big of a difference. Rarely have to fill up the rx7 because it only activates at low boost. 

[MPlayle]

In one of the videos about the turbo kit, Jeremy mentions using 28* on a turbo'd 998, so I thought the 18* he said when discussing the purchase seemed off.  That is also why I was going to measure the current advance at 4K rpm (vacuum disconnected) for comparison.

I looked up the 123BT: $575 if ordered direct from the 123 USA division!  Also, I don't have a compatible device for the software.  The only Bluetooth capable device I have is my Macbook-Air running MacOS.  The 123-Tune software is made for either Android or iOS (iPhones or iPads).

[MPlayle]

I plan to keep the boost on the lower side - 8 to 10 psi max.  The afore mentioned video of a turbo'd 998 was also limited to 10 psi max boost.

[94touring]

I'd run 30-32 degrees out of boost with vacuum connected giving 40-42 at light throttle, and 22-24 degrees at 10psi. I'd get a device that works with a 123bt.  But I also would run an intercooler or h20 because otherwise you are surely on your way to sadness, broken stuff, and a crappy running turbo setup with poor fuel mileage and really hot egt's.  Your oil temps will also be hotter and you may need to factor in that as well.  Oil cooler or synthetic at bare minimum if your temps are getting out of control for conventional. You'll know if it works or not on a hot day doing sustained hill pulls by going the easiest route possible. 

[MPlayle]

Now you are just scaring me out of undertaking the project.