stumc's supercharged puma: 26/03 rolling road + rebuild woes

[madhillbilly17]

I see

How about a variable controlable fuel pressure regulator? One that boosts fuel pressure when on bost, but goes back to standard when off boost..

fmu thats what i would have gone for if i didn't go standalone

 

[Noobrider]

loving the cut down dash

 

[stumc]

yeah the FMU/rising rate regulators were something i looked into. my mate had one on a turbo'd MX5 and struggled to get it fueling right, they come in different specs, different ratios of adjustment in relation to the pressure they see, this means youre pretty limited in regards ajustment from what i understand. with my setup i can adjust the fueling upto atmospheric MAP, then the 5th injector kicks in and i can adjust that, while the engines 'on boost'. quite a few people have said theyd rather go the rising rate FPR road but tbh, this works well, and i recon probably better. each to their own!

 

[stumc]

well since my last update i hadnt done a great deal other than tinker with the fueling until this weekend. got it running a bit leaner, on full chat its now in the 11s which seems more reasonable, and on the cruise its high 12s. ive got a slight flat/lean spot up until 3k under full throttle but the simple solution for now is to drop a cog before i boot it. im planning on faffing about with it this weekend though, bringing the 5th injector in earlier and and increasing the duration, then dropping the fuel pressure slightly. we'll see.

anyway last weekend i had the engine out and replaced the crunchy gearbox, clutch & slave cylinder and timing belt. i also changed the aux belt idler pulley and water pump as the bearings felt a bit rough, and the aux belt tensioner as a matter of course, all in the hopes of shutting up an annoying rattle ive had since i bought the car, which has gotten slightly worse recently. i noticed there seemed to be alot of movement forward and backward in the crank when i was removing the pulley though, which worried me slightly... after getting the engine back in, the rattle is still there so im assuming its the crank which is the issue new engine time then.

im on the lookout for a replacement engine to drop in next moth, then planning on doing some mild DIY porting to the head from my current engine in time, which will go on with a copper headgasket as some stage. ive just bagged a new intercooler from a mk4 golf turbo for £13 on ebay! slightly bigger and better layout than the ERST jobbie im using at the minute, which will hopefully allow it to breathe better. at the minute the throttle response isnt the best compared to what it was, making heel toeing a bit trickier. hopefully having fewer bends in the plumbing, aswell as slightly bigger diameter hoses will help.

thoughts and sugestions welcomed as always!!

also got a 390mm saxo rad and slimline fan, to give me more room for the new I/C, and ive got a few other little jobs to do like stiffening the engine mounts up with polyurethane, welding a new 2.25" downpipe to the ashley manifold, (its currently 2", into a 2 1/8" flexi, into the 2.25" FRST system) which should free up the breathing a bit too. then some general tinkering.

hoping to have the car on track a couple of times this summer, if i can get all that work done in time ive got a week off towards the end of march, hoping to get a day in then!

 

[Cartman]

sounds like you'we been buissy

love this tread

just a slight thought, are you doing anything to counteract the copper head gasket from coroding the aluminium head, and bottom end?

 

[stumc]

cheers mate!

ill look into it when the time comes but as far as im aware copper head gaskets are coated. ones i looked at for cvh engines and the ones my stepdad had fitted to a mondeo v6 engine years ago were.

 

[Ziggy]

why not simply purchase a thicker 1.7 head gasket instead of messing around with a decompression plate and 2 gaskets etc? I'm sure someone does them in different thicknesses.

 

[stumc]

the copper headgaskets can be fitted straight into the heads without gaskets either side as far as i remember.

been for a spin today and thinking about the AFRs. its running rich at low load and idle now, still got a slightly lean spot under 3k, then runs a little bit leaner on full chat over 3k. i was wondering what could cause this then i started paying attention to the boost gauge and under full chat its dropped to close to zero (gauge under-reads so probably 2 or 3 psi). the car still goes really well, id say maybe even better up high towards the limiter. and it dawned on me, i had to adjust the inlet cam slightly when i replaced the timing belt, rotating it anticlockwise as it was a smidge out, therefore slightly retarding it. this would explain the change in AFRs. at low load and rpm there will be less scavenging, so less air and a richer mixture, bit higher up its better off hence leaner mixture.

once thats sorted ill have to figure out how to get more air into from the blower, although i think the new intercooler will help.

 

[Puma_Sam]

Just been reading through this project Stumc

Some fantastic work you have put into it, or so I think as 90% of it is over my head!

well done and thanks for the advice that you have been putting my way.

 

[stumc]

cheers mate! none of it is really that complicated, its all basic stuff when you get your head round it! everything ive done has been self taught over the years, its just a case of getting stuck in with things and learning as you go. im sure youll learn loads with your project! if you have any questions on anything then let me know, i certainly dont know everything but im happy to help with what i do know about!

 

[stumc]

what a cock i am

when i refitted the engine, i changed some of the vacum lines, and used a T piece on the dumpvalve for a line off to the boost switch, not putting 2 and 2 together when the boost disappeared...

so today i took it up to mikeanics in congleton for a quick power run. my mate has been commenting on it feeling slower, and i wasnt sure if it was in my head or not, but i had thought it was going better. i think now its just because the way ive been driving it differently, paranoid about the flat spot, and it breathing a bit better at the top end, i think i was imagining it :roll:

anyway, it made a measly 130bhp at little or no boost. i went back to my lockup, faffed about and realised the dumpvalve was staying open, bleeding off boost. i took it off and it seemed to work fine off the car. then the penny dropped.....id used a fucking connector from a windscreen washer pipe which had a non return valve!!! fucked this away, replaced it with a straight bit of pipe, and its back to making boost and going much better.

hoping to get the new radiator and intercooler setup installed this week then get it back to mikeanics on wednesday if all goes well to see what its making.

what a fucking clart!

 

[moondustka]

Don't worry..

It's taken me all this time to realise my heating/cooling issues is because I've made some slight plumbing errors!!

:roll:

Such is life. It's all a learning curve

 

[stumc]

yeah its just such a dopey thing to do but no harm done.

had the car back on the rollers on wednesday, showing 3/4psi it made 155bhp and 144lb/ft. ill get a picture of the graph up at some stage, the power curve is spot on, really smooth and still climbing at the limiter which is nice. the torque curve shows the slight flatspot ive got but isnt too bad at all really.

i know its the standard 'go to' line :lol: but the rollers genuinely seem to under read. my mates E46 325 is 190-195 from the factory and made 173. another friends 3.2 audi a3 which is 256 from factory, plus a remap, made 216! and in the past, weve had an s2000 be down 30bhp, and very quick MR2 turbo and MX5 turbo make less than expected, at 238 and 172. we recon between 10-12% under actual figures working off a rule of thumb, so if so mine should be around the 170 ball park which seems reasonable. either way, the arse dyno never lies, and its saying its pretty quick :lol:

ive had a few days in the workshop this week, spent 2 days sorting the stripped down loom of my mates puma, refitting whats left of the dash (his is even smaller than mine) and finishing welding up the floor, rear sills and one rear arch replacement. so mines taken a back seat.

did a mock up of the new saxo radiator and mk4 golf intercooler. got a couple of bits of silicone and some joiners to order to fit that new setup. got the mondeo V6 throttle body properly fitted to my spare manifold, and ported the opening to suit. thats ready to go on the car now but i need the correct TPS plug to wire into my car. cant fit the puma TPS as the throttle plates rotate the wrong way unfortunatly. will probably wait to fit that lot with the new engine ive got to go in, along with the M62 and megasquirt.

on the subject of the new engine, i picked up the rebuilt parts on wednesday afternoon and set about rebuilding the engine wednesday night. got it stripped down, and discovered a few of the big ends showing signs of wear. fitted the new main bearings without a hitch but the big ends turned out to be wrong. ive been supplied 40mm bearings which according to a quick google search seem to be what the engines meant to run, however my crank has 42mm big end journals... :? i took them back to eurocarparts and they are the only size their catalogues list, as do most suppliers i looked at from the google search. ive got the number for the product manager at the eurocarparts HQ in london so im going to speak to him, and do a bit more research online. seems very odd though. its an MHA engine from an early/pre facelift car, so if anyone can shed any light on that itd be greatly appreciated....

im off to the usa in a few hours (pulling an all nighter tonight so i can kip on the plane!) so the car will be untouched for the next few weeks but im planning on smuggling the supercharger, megasquirt and a few other bits and pieces back with me, so will be plenty to do when i get back!