So update on the various goings on:

Took it to the dyno, headline is it didn't make anymore power. Made 345bhp / 309whp compared to 352/3bhp / 312whp. Made the same peak torque at 265lbft. What is interesting is it made this peak power at 7200rpm rather than 7400rpm, and the power curve actually rolled over. We revved it up to 7800rpm but it didn't make anymore juice. We tried adding a bit of timing but that had no effect, then reducing timing decreased power, so that feels pretty optimised now.

Interestingly the car was more responsive to fuelling changes this time around, it was running a bit rich when it first arrived and we pulled fuelling back to 11.5 to 12afr and that got us back to the 345bhp figure from 325bhp it came in with. Previously the car didn't mind running low 11s high 10s. On the road this translated as the car getting its zing back. I gave it a good pull up a hill on the way back and it felt awesome again like it did when I first put the new cylinder head on early this year. I think with the faff with the water injection, rebuilding with a few changes etc it had just fallen out of tune a bit.



The changes this dyno session vs last were:
> +1 intake valves - haven't made a difference, maybe they require some more cylinder head to unlock them.
> New manifold and inlet for throttle body - hasn't made a difference over last time.
> New chargecooler. Has lowered PR everything else the same, increase in air temp over a dyno pull has reduced from about 10degC to about 2-3degC, hasn't made any change to power, atleast on a cold winters day.

We moved the intake cam around and actually found this time we made slightly more power at around 108atdc (max lift), where before it preferred more advance (102atdc max lift). Retarding the cam increases boost pressure. But as it made more power at 108 I guess 102 actually just had too much overlap, just blowing charge straight out the exhaust, lowering boost but wasting air and fuel. I sort of wish I hadn't added +1 intakes because I think my original standard size but aftermarket intake valve head from last year was actually a bit of a sweet spot. Maybe the +1s need a bit more of an aggressive deshroud to get them working for this application. Anyway I feel like the development has run its course now.

I also made a larger pulley for the supercharger, to go back to the 2.2 ratio I ran on the very first dyno session in 2020. When I added my 2.5 ratio pulleys they didn't add any power at that time, and if you've read this thread from the beginning you'll know I've never been 100% on why. So I was interested to see if the car would just go and make 350bhp at 2.2 ratio this time around.

It didn't. It made 327bhp / 288whp / 240lbft, at about 0.7bar of boost. I'm pretty happy with this. It is a lot of power for the boost level, without overspinning the supercharger. It will only be outside its continuous rpm rating above 6800rpm, and well under the intermittent rpm for the sc. This will really help the supercharger on a hot summer trackday, without water injection through it. Also, as the map used to pull 1-2deg of timing by the end of a straight due to AITs, if the larger pulley avoids this then there isn't really any trade off on power anyway. I think this is why the 2.5 ratio pulleys didn't make more power originally. It was a really hot day, the ECU pulled a couple of degrees, and we didn't see the power. Wish I had taken logs from those sessions but there we go. But mystery solved I think.




I had a track day today in the car, but to be honest nothing to report. It was really foggy and they couldn't open the track up properly. Got one run of 3 laps. It was very cold. With the new chargecooler aits haven't shifted at these low ambient temps. On the move, the car runs air temps of 25-30degC. This is basically the case from ambient temps of 15degC and below. I guess it is because of the way the setup is bolted to the cylinder head that also runs at basically the same temp independent of ambient conditions. Below is a comparison of a run on the same track on another cold winter trackday from 2021. I was sat in a queue to start with hence the higher starting temp but you can see overall the temps recover to the same sort of values.

Log from today is bold, faded is from 2021
So basically, larger chargecooler does decrease temp increase over a pull, but overall at low ambient temperatures the overall average running temperature hasn't been affected. Will be interesting to see the data when the weather gets warm again. Will feedback on that next spring / summer.

Anyway, I am going to stop messing with this setup for a bit. I feel like it has reached a zenith and does exactly what I want it to do, and that I have explored the various paths I wanted to. If you follow my facebook or instagram (Coldside Engineering) you will have seen I have started to build a kit around the TVS (HTV) 900 supercharger which is to sell, which is keeping me pretty busy. Setup will be like my car, coldside, water to air chargecooled, performance should be equivalent to the setup I have developed in this thread (will be dynoing), but engineered not to be such a pain to install, keeping the alternator where it is, the ability to run ac and ps, not having to move the clutch master etc. It is a 2 core chargecooler, to keep things a bit more compact, with a nice cnc'd manifold that I am pretty jealous of and may have to get one machined for my car. So get in touch if you are interested in one of those.

Saweett!

 

That's a short nose blower, non-MX5? Or is it repositioned in relation to the pulley plane? Oh wait, do I see Harrop there?!

Great work, always been a fan of these since a local had one on his NA, and the competition was the JR kit.

 

Thanks Gee Emm. Yes it is a Harrop manufactured HTV/TVS900, it actually has a fair snout on it to be fair. It is positioned to run on an additional pulley mounted in front of the crank pulley, rather than my car which has its supercharger inline with the old ps / ac belt run. I did this to allow use of ac and or ps. Also allows you to slot a tensioner plate in between the alternator belt and the supercharger belt - means the alternator can stay in position.

 

Thanks for that info, I knew they were doing installations for the big bent 8s here, so seeing the name was not a total surprise. Will be following with interest, though I think my caravan has departed as regards my FI commitment to the current build.

But never say never ...

 

Very interested to see how the TVS900 setup turns out.

 

Yes most of their kits are for big v8s etc. Well, get in touch if plans do change.

Thanks mate, yep me too

 

New guy here and I hope you have enough pity on me to help me with my issue.

I have an older Kenne Bell supercharger and I am trying to take it apart. I've taken the bolts out, but I cannot separate the housings. I suspect you had the same problem and I am assuming it's just some sealer/Loctite. There does not appear to be a place I can get under to pry it loose. What was your trick to get them apart? Heat?

Thanks in advance.

 

Replied to your DM Butcher, but I've never had my supercharger apart personally. I do know there are some internal components in the rotors that need to be undone from the gearbox end before splitting. But I've never been inclined to roll the dice myself as my rebuilder Pete is so reasonable. I know enough to know I don't want to mess with it

 

I've recently got the TVS900 kit on my car for testing. It is a bit of an animal. I am spinning it slightly faster than my Autorotor, as it has a higher max rpm, but the boost curve is certainly fatter from lower rpm than my 2087. So much so that it slipped the clutch in the midrange, and I have had to put an angrier clutch in it to hold the extra power. It has also over maxed my injectors, I am at about 97% duty by 7000rpm. So I will wind up the fuel pressure a little to get me by. It is a little quieter than my Autorotor in the cabin, but still makes a great noise. Still very much supercharged. Apart from the clutch and the injectors, only snag with it is the idle valve. The throttle body I bought has two tiny m5 ports for qn idle valve. I tried to use them but no particular surprise they were completely inadequate. So will have to come up with something else but no particular drama. On the dyno next week unless it snows.

 

I did reply back. If I ever do find an answer, I certainly will be back to post what I found. There are rebuild 'kits' available and I suspect there is only one way to do it right. I am just wanting to take the lobes out of the housing to clean the housing out a bit.

Thanks for reply.

 

Got the clutch swapped out and hit the dyno.

Got the fuelling dialled in and it made 365bhp, 326whp, 281lbft of torque. Very happy with this. Was a bit lucky because the barometric pressure was quite low, which bought me the duty cycle on the injectors to just about be ok, running them right up to and slightly over 100% duty. It also bought boost down a little to roughly 1bar in the top end vs the 16+psi I was seeing in the high pressure weather when I first got it on the car.

I've spliced in the torque curve from my Autorotor into this graph, sadly power was on a different scale

It's a decent wedge over the Autorotor. I am spinning the TVS faster - using a 2.57 ratio rather than 2.5, but the TVS is still under rpm limits by a decent margin whereas I am overspinning the Autorotor.

TVS is making 6% more torque about 3% more pulley ratio. It is a very impressive unit, I am a bit gutted to be selling it to be honest. You can really feel the extra torque on the road. Took the long way home and it was hilarious.

The chargecooler is working well. It uses 2x 45mm Laminova cores. My old 2 core used 2x 40mm cores. I was gaining about 9-10deg in AIT on a pull starting from 2500rpm up to 7500, the old 2 core is essentially the same, but it was dealing with a lower PR, less boost, less power. We did some more extended runs with several pull linked together to try to simulate some track driving, and it did great. It is interesting, once it gets up to temp, air temp actually starts reducing on a pull and it runs hottest on the overrun! It wasn't a massively long run, but only gained about 2degC over starting temps and it had stabilised. So happy with that. It was a cold day but, these setups tend to run at about 30degC base temp whatever the weather. The intake temp sensor is so close to the engine I think it picks up the heating effect on the air from the cylinder head. Then that base temp stays pretty much constant up to about 15-20degC atmospheric, then you start seeing the atmospheric temperature adding to that base temperature by about 20degC. I was wondering if I should have done it with a 3 core, but the extra width that requires made it a far more difficult install, so I am very happy to see the performance of the 2 core being so good.

 

And a video of a pull

 

Hi, been a while. So the first TVS kit sold and I installed it on a freshly restored mk2. Stock mk2 engine.



Really pleased how the install went, it was nice putting it on a less cut up car. It is running an Ms3 mini ECU. First fire up and it purred like a sewing machine. I did have some fun with the idle valve circuit making a honking noise on idle. I didn't hear this on my car because of the airbox but with the open filter on this car it was very annoying. Resolved with smaller idle valve pipework, but that did limit the effectiveness of the idle valve. Definitely going to move to a different throttle body on future kits that allows the valve to be bolted to the bottom of the throttle without pipework like on my car, far less hassle. Got it on the dyno and it made 270bhp / 244whp with with a 2.4 pulley ratio. I didn't bring my smallest pulley because I didn't think we'd need it, but at 215lbft we could have pushed it a little more I think. It made that power at 1bar boost. It would benefit from a cold air feed for hard use, which is something we might do in the future. Packaging with the comedy size filter is difficult so there may have to be some compromise on that. But the owner is very happy with it and has been to loads of events with it without any issues, so I am very pleased to have achieved that.

With the TVS kit sold I have chilled a bit really. I painted my bonnet and boot lid blue for some reason. More interestingly I switched my oil cooler to a Laminova type, positioned in the bottom rad hose.

This is the C43-180 model. I can't say it has been a massive success, I should have bought one of the twin core ones I think. I found some oil pump flow rate data after I'd already bought the cooler and that showed flow rates of around 50l/min at 60psi. The coolant flow rate is a bit of a guess, particularly as it is in a loop that doesn't see massive flow with the thermostat closed, and my car bumps off the thermostat the whole time. The coolers aren't hugely sensitive to coolant flow rates anyway, it takes a big increase to induce quite small oil temp changes (Laminova and my own calcs show this). You can make a step change in cooling ability by running restrictors in the coolant passage, at the expense of restriction at higher flow rates. The issue is because of how I have placed it, restriction will induce lower pressure at the water pump inlet and so make cavitation more likely. I could overcome this by reintroducing an electric water pump, but I'm not really sure how much effort I can be bothered to put into it and may go back to a traditional air to oil cooler. That brings us up to date, just having fun doing a few events over the summer. The TVS kit is available so get in touch if you would like one, Coldside Engineering Ltd. Got some cool stuff in the works soon too.

 

Hi everyone hope you all had a great Christmas and New Year.

Been up to a few bits and bobs since my last post. The main project being a supercharged Exocet, which has been a lot of fun. They weigh a little less than 700kg apparently. Tube frame with Mx5 running gear. The project escalated somewhat, ending up with me rebuilding the engine for it (the short block supplied for the job was in bad condition, scored bearings and didn't have the forged rods it was supposed to have), along with a full exhaust and a simple water injection system. The supercharger itself was another Autorotor 2087 (new old stock - unused!) put together with my old manifold and chargecooler.

Space is a bit tighter width wise but access is better because of the tube frame. I had to move the brake and accelerator pedal outboard 20mm and rejig the brake fittings to give the required clearance. Luckily the shock tower didn't need modifying, just about.





It was quite interesting test driving it in the November / December weather with no windscreen and 430odd bhp per tonne. We are dynoing it soon to finalise the tune. Surprisingly it wasn't too lethal, it gripped well and was very predictable. It was very easy to slide around and was great fun. It did make me think about future projects for myself.

On my car, I have redone the cooling system. I wanted to fit a larger Laminova cooler, and to do that neatly it necessitated changing the radiator (which was leaking anyway) to a twin pass to get the inlet and the outlets where I wanted them. I then leaned them forward to create more room for the oil cooler. I've fitted a load of sensors, oil temp in and out, oil pressure, coolant pressure in and out, coolant temp in to get data on how it is performing. I have put a medium sized restrictor in the cooler to increase oil cooling but that increases pressure drop for a given coolant flow. There is a bit of a game in sizing the restrictor to maximise oil cooling while keeping pressure drop reasonable for your given coolant flow rate. There is a sweet spot where restricting more doesn't really do much more oil cooling but has a large increase in pressure drop on the coolant side. I'm hoping the pressure sensors help me judge that. I haven't got them wired in yet but from my first test drive it is looking good so far. I have a track day beginning of feb to give it a proper shakedown.


Anyway thought I'd post a little update if anyone was interested. Working on some cool projects this next year along with some fun trips.

 

Hey! Found you on OneLap Heros!


Edit: Just finished watching the video. Super entertaining to see you talk about the car. I just love the vintage looks you have going on, totally approve.

And great to see the car on the ring! She friggin' sings man, at first I was skeptical of the 300+whp since it doesn't come on quite like a turbo setup, but man, that thing has some top end! Very cool And honestly great job out there driving the ring for your first time with the passenger coaching. Looked super fun and I think you did a great job out there.

One of us! One of us!

 

Ha ha yup that's me! Many thanks Fireindc!

It was an awesome trip. Some friends and I went over to the SPS motorsport season opener in Germany. At the opening party Kostas was interested in my car so we shot the spotlight video just before I went out on the ring. The video is of my second lap. It is a mad place. I've played it on games before but it doesn't really convey how hilly and blind so much of the track is. It is also narrow, with no run off most of the time. Amazing experience but I was glad to do a couple of laps with some guidance and still have the car in one piece. Adam, the guy in the passenger seat guiding me has done more than 500 laps there, and he took me out in his 300bhp turbo car. The man can drive, and you can tell he knows the track so well. You need to to be able to push there.

Yes the power band is quite biased to the top end. In reality the car is not really much quicker than say a 280-300bhp crank turbo car up to about 5500rpm, but above that it really starts showing the extra top end. I guess that may be different to what people would expect from a positive displacement supercharged car but I like it.

I did about 2000miles that trip in total, topped out 6th gear at 7700rpm with a 3.6 which apparently is 170mph, two laps round the ring and gridlock through Brussels and it didn't skip a beat. Really happy with that.

Appreciate the kind words and glad you enjoyed the video