Supercharged AJP8. one last step!

[a1rak]

didn't get to finish my last post, so If we suck cold air in from the underside I thought it might reduce engine bay temperatures. When I get my bonnet back on I will try it and see what happens. I post up the results

[a1rak]

gerradiuk said:

a1rak said:

The pump is a davies craig EWP, they have a good web site so you may find your answer there. I would have thought that you need either a head of water or some sort of back pressure / restriction to generate pressure against the impellor and an engine cooling system is going to be designed specifically to avoid this. What was your intended use for the EWP.

Paul I am thinking of fitting a pump as for peace of mind in traffic as you are, but the pump I have is not the same, its a double diaphragm type & was thinking it may impede the flow when not in use?
Also on my pump it says 30psi but has a lower per ltr rate than your Davies Craig pump hence the question, was concerned incase it over pressurised the system?.

By the way how is the S/charger going ?

I wouldn't fit a lower flow pump as it is a high flow that is required. If its a diaphragm positive displacement pump then I cant see how the existing mechanical pump will push water past it unless I have misunderstood how your electric pump works. I think the EWP's 115lts is fine on the AJP for heavy traffic but I would not be happy with this flow with the engine being pushed hard hence leaving the original mechanical pump in situ. I need to fully test my set up and as my car is going for an MOT this Saturday I may be able to tell you how well it works in the next few week.

The supercharger and engine are working great. Just a few minor niggles the main one left now is getting a dump valve to work correctly. At the moment when you lift off the throttle the engine does not slow right down to tick-over speed quickly as the plenum is holding pressure. I need to dump this excess pressure but its proving slightly more difficult than I thought. The boost is blowing the throttle open by small margin so you are not getting a good vacuum to operate the dump valve. I going to try a larger bore pipe from the dump valve to the inlet, fit a weaker spring in the valve and see if this solves the problem.

[a1rak]

Thought you might be interested in some photos of the inside of the plenum on the supercharged cerb. I stripped all the inlet system off for its first health check. Going to get it all machine polished as it seems to work well.



This is the only problem...these bloody heat barriers and O rings. They were new when I fitted them about 500miles ago! I don't think I have ever seen one yet that has stayed intact on an engine. I think I might get some solid PTFE ones made up out of 8mm sheet. Should solve the problem once and for all. Anyone done something similar. Could get some additional ones made if anyone's interested.

[a1rak]

Had some new PTFE inlet heat barrier / gaskets made. shouldn't crack like the Tuffnol ones and nearly let the O rings get sucked into the engine. Will use a smear of silicon to ensure a good seal.

[a1rak]

ridds said:

How much are the PTFFE barriers (if it's not too late) do you think you could machine a groove for the o-rings?

Any reason why you didn't bell mouth the throttle intakes? Is it purely a space constraint?

Looks good though.

I might look at fitting some very small bellmouths when I re-assemble the plenum. Space is an issue but even a small trumpet may help.
The PTFE barriers end up about the same price as a new tuffnol unit about £50.00 each. Its the o'rings that cause the Tuffnol barrier to fail as on my engine as the ports have been very slightly increased in size when the heads were ported. To get the barriers to match the ports you have to remove some material from tuffnol barriers which leaves very little material before the O'ring.
I could try and get some slightly larger O'rings but then they may be to big for the inlet manifold. The PTFE is a very good gasket material in its own right so hopefully with a smear of silicon it may be a good seal without O'rings.

[a1rak]

Weather is crap promised myself I would not do any work on new years day so decided to upload some more recent pictures of the engine.

This shows the inside of the plenum with the addition of the small ram pipes.

plenum cover on and all bits polished. One benefit I did not realise is that it is far easier to keep clean than a painted engine.

This picture shows the extensions on the inlet manifolds which lets me run the injectors on the engine side of the butterflies.

[a1rak]

The ally parts are just polished no lacquer. The water rails and other steel parts are also polished then sprayed with engine lacquer.

[a1rak]

Thought it might be worth updating the thread with my winter additions. This winter I decided to wire ring the block and fit copper head gaskets. The standard composite ones had not failed but if driven hard then they would begin to seep. I think this is common on the AJP. The car appears to have a failed gasket when driven hard but on a strip and inspection the gaskets are fine. In discussion with some specialist it would appear the standard gasket can lose its seal if the engine gets hot and is pushed hard.

The gaskets were ordered from Ferriday engineering and are extremely well made and fit perfectly. They do need annealing which cost another £120. I also fitted new cylinder head studs. These gaskets need re-torqueing after an initial run which is a real pain as you need to remove all the intake again. Was really surprised that with a hot engine virtually every bolt turned around 1/3rd of a turn before the correct torque was reached, so was well worth doing.
engines now in the car and running but no supercharger back on yet. will get some more pick up when finished.

[a1rak]

Thought I would bring the thread up to date. Just fitted and tested methanol / water injection on to the Cerb. I used the Devilsown kit made in the States which was well made and had good reviews. Its a single nozzle system that I have modified to trigger via the Emerald ECU. Its set to trigger at boost levels above 3.5psi and 4000rpm although this is easily changed. I logged the results on the laptop and without the Methanol. Inlets temps rise with boost so at 2psi I had 32degrees today and this would risewith boost to about 45deg at 7psi today.
Turned on the Methanol and temps started at 32deg, started to rise towards 40deg but then the injection started and there was very quick drop back by a to about 35deg, if I pushed the engine hard the inlet temp never rose above 39deg which is much better than it used to be. I have seen over 60degrees before and it would regularly go above 50degrees. I will get the car mapped again as I have done a fair amount of work on the engine since it was last setup by Emerald about 2 years ago. Couple of pics to show the install.



Mounted the pump and bottle in the boot. Its quite easy to install, ran the pipework inside the car then through the bulkhead into the engine bay.



The nozzle is mounted just after the Supercharger and before the plenum. You can just see the injector and black pipe before the bend on the inlet pipe. If you use the 50/50 mix then apparently it increases the octane level to around 116, Inlet temps, exhaust and combustion temps also drop significantly. Hopefully with a re-map it should be a safer engine with a bit more power.

[a1rak]

Winter upgrades. Replaced the old rad with an aluminium unit from Arron. They made some thicker cored units for Topcat Racing so decided on this as the best option. Not a perfect fit, sent the first one back. Second unit better but still needed minor modes to get the fan cowls to fit. Old rad must have been partially blocked because the running temps are significantly cooler.
Engine temps in heavy summer traffic have always been a worry and have spoilt some journeys. Hopefully now a thing of the past.
Also removed the aircon condenser rad so the airflow now hits the main rad straight away. Off to Castle Coombe on the 13th Feb for an early season trackday ! anyone else going.

[a1rak]

No not been on the dyno since Austec when the ACT exhaust was fitted. Hoping to get back to Emerald in the next few months so they can trim the map to allow for the water injection, may try a slightly smaller charger pulley at the same time, not looking for more power but maybe the same power at slightly lower revs. Will update the thread as work continues.

[a1rak]

Update on the recent work completed. Original BTR diff was getting noisey and clanking when braking and accellerating. I manage to borrow a 4 poster ramp so took the oppotunity to complete a lot of work.

Removed the diff and had a Quaiffe ATB LSD diff fitted whilst having the diff fully rebuilt by Competition transmission services. Also replaced all the diff mounting bushes at the same time which wear totally knackered.|https://thumbsnap.com/xJM2QT9H[/url]. I have no idea why this image keeps loading upside down so you will have to stand on your head to look at it.


I try and treat the chassis each year carefully with a wax based rust preventor so decided this year as I had a ramp to clean all the old stuff off and put new on. I was really pleased with the condition of the chassis, there are no signs of rust anywhere including the dreaded outriggers.

I also have upgraded the engine breather system to a twin outlet setup, the last single pipe one was too low on exiting the front timing cover so used to get quiet a bit of oil travelling up the pipes. This time I have taken the outlets from the top of each cam cover box and feed to a central tank. There is also a feed back to the sump that can be open and close with a valve. Looks much better and hopefully will work better too.


Fitted a genuine new clutch master cylinder and heat protected the pipe with thermal wrap all the way down to the gearbox.
serviced the whole car, new brake fluid, oil filter and supercharger belt. Removed the exhaust had it repacked and a couple of cracks repaired under warranty.

I have had a few short drives and diff is great no clunks and bangs. Clutch seems a bit lighter. Just need the weather to improve and take it out for a good spirited run.

[a1rak]

Yes castle coombe last year. I will be going down there for a track day on the 10 March, anyone else going?. Depending on the weather dictates what car I will take out. I usually take 2 cars for a whole day on the track as its to harsh on 1car. I will probably take the Cerb and the my Peugeot which is much better in the wet.

[a1rak]

Long time with no updates on this thread so just to keep the thread up to date as I like it to reflect the work an issues ive had owning this car. Joolz dyno shoot out made me get my finger out of my arse.

So, Completed a full engine service and compression test on the 04/12/2019 very health numbers all reading 10.5:1. fitted new plugs, new supercharger belt, smaller pulley and engine oil and filter. Attended the recent RR session , Thanks again Julian. Engine has had no issues but does not get much use so did not know what to expect, obviously pleased.

figures taken on the 07/12/2019

[a1rak]

Another update on the supercharged Cerbera. I posted earlier about lack of rear end traction and grip, its not a handling issue its just lack of grip. It may have just been the Pirelli P Zero tyres, I'm just not sure.

I was at Snetterton a few weeks back and still suffered the same problem so decided to go to town on sorting the issue.

1. Had a full geometry check and set up with 1mm toe in and 2 degrees camber on front and back.

2. Full brand new set of AR1 track tyres 255/35/18 Rear and 235/40/18 Front.

3. Full carbon rear wing. On a spare boot so have not used the original for the purists amongst us.

4. Disconnected the Rear ARB.

I'm down at Castle Coombe tomorrow the 24th so WEATHER PERMITTING will let you know how I get on.

[a1rak]

Had a lot of interesting fun at castle Coombe trying out the new parts on the rear.

I was really lucky as AST suspension had a couple of guys down in the pits offering advice and support. They were very interested in helping out with the Cerbera .

The first time out the car was as follows

Pirelli p zero tyres 30psi hot
No ARB
Wing quiet steep
20 click up on Nitrons

Car was very soft at rear grip level better than the original settings but the car dug in far to much on acceleration.

Second time ou as above but ARB connected.
Very similar but less lift of bonnet on acceleration, didn’t notice any difference in grip.

Third time out ARB connected, 25 clicks on Nitrons, less angle on spoiler. Again an improvement but not game changing.

Fourth time out ARB connected, 25 clicks on Nitrons, same angle on wing 10degrees approx, Nankang AR1 track tyres. Big big difference, massive levels of grip no drift or oversteer exiting corners and power down much earlier. Braking more stable. Only issue was the car still digs in on acceleration enough to make the rear tyres run.

Unfortunately the car developed a high RPM misfire in the afternoon so had to short shift.

AST were great and I think the setup will be great with a stronger set of springs on the rear. They are 325 atm so going to go with 400. Hopefully this will reduce the lifting on acceleration.

I don’t know what are good times around Coombe but even short shifting at 5000rpm I was managing 1.16. I recon with better springs more time in the car and no misfire 1.13 are possible.

I’ll update the thread each time I make changes or modify to the car. Hope you find In interesting.

[a1rak]

after reading all the replies and suggestions im going for 475lbs at the rear. hopefully a good compromise for a track car that is used on the road.

[a1rak]

I’m running 255 35 18 at the moment and they already rub on the drivers side under hard cornering. I’m going to fit the 475lb springs and try them.I want to check the clearance on the inside of the wheel. Maybe the offset is not ideal but I’m fairly sure 255 is very near the maximum I can fit on my car without body mods.

[a1rak]

That’s worth considering. I don’t mind modding the lips and inner arches I was just trying to avoid body mods that can be seen from the outside. I did take a portion of the inner arch away to reduce the rubbing but was not going to do any more until I had the rear uprated rear springs fitted

[a1rak]

Yes that was me. It was great fun with a big spectrum of cars. The Cerb still has a major cut out / misfire at just under 5k rpm which is really annoying so still have to short shift.

Going to change crank sensor as the laptop mapping shows the rpm dropping from 5k to 0rpm instantly.

Will probably change coil packs and ht leads at the same time whilst I’ve got everything apart