GTA hillclimbmonster

....the lightweight pistons will have a hard life
Plan was to use the garrett gt28/71/53.1mm bb-turbo, the bigger one with the 53.9mm/76 trim turbine wheel, but doubts coming up that it will do the job. As we want to do the the pre turbo tubing as compromiseless as possible we where looking for a twinscroll housing and found one, it's a 0.82 a/r. The other option to try out will be the 0.63 singlescroll. But anyway maybe all in one to small, it's not the best match, as the turbine outlet is pretty tiny even the wheel is aerodynamically much better designed then the earlier ones. I've planed to use two small external wastegates, one each turbo uppipe, will help to pass the loads of gas on high revs, but as Martin said, it will be a very experimental project, maybe trying what we have and look how it performs Think a gt30 variant would be a better match.
However i count on Martin's experience about matching turbos and hope you'll not advise me to throw in the bin what i have....

I run a .63 (T35 they called it) Turbo Technics special hybrid on my 3 litre GTA and I think it would prove a little laggy on a 2.5. Turbo choice will be critical to track time so its essential to eliminate lag and usually this will gain you more time round a circuit than a few more horses at the top end - and gives the engine an easier life too. The Garrett GT series is a better more modern design that the old T3 T4 series and flows much better with less lag and would definitely be the way to go :0).

Thanks for your opinion Tony, thinking the same.
But a guy i know compared the 0.82 twinscroll on a BB turbo with a 0.63 singlescroll on a non BB and told that he did not notice any increased lag, but he tried it with different manifolds so not 1:1 comparable. As we use the car for racing the rpm range will rise, the heads, valves and high lift cams will pass much more air/gas. Martin told me once that the compressor will be struggling too. There is still too much hidden in the fog i think! Always interested in others experience!

Martin,
Are you going to be using a winged door type sump baffle to prevent oil surge on this engine.
CheersEddie.

Hi Eddie,

How's it going, any news on your own projects? Hope you and yours are doing great, not heard from you in a while.

As to the sump, yes I think it would be wise, I have a baffled barn door sump that Chris can copy, fabrication isn't really my best thing. Saying that, have you got, or going to do something? The Volvo FWD winged bottom plate and sump would be better than the GTA one, but won't fit in the OE sub-frame. I know you don't have that issue on your project car, but would be on Chris and most other applications. I guess this would be a product right up your street. On that point, have you finished a set of the adjustable suspension arms etc? I'm still in the market for them Eddie..

On a different point, do you get involved in the 4 cylinder and straight 6 cylinder BMW engine tuning / modification? Do they do anything different from the 4 cylinder to the straight 6 on head mods etc?

Cheers,
Martin

.
Fashion exhibit no. 1, come in all shapes and sizes, and will always flatter the most voluptuous lines and curves...

So here you go, forged pistons modified to take Cossie top compression ring, and oil control ring for better longevity, nice and light item, short taper pin, and rigid construction. Rods modified to match, longer than OE to get the crown where it needs to be.







All balanced up (pistons, rods, crank, front pulley, flywheel and clutch pressure plate assemblies) and ready to rock’n’roll…



Hey ho, on to the next stage...

Are there no easy options to convert to dry-sump for your application Martin?

.
Hi Darren,

Yes ultimately this is a good idea, and much merit, but at this time cognisant of costs, then I think this is something that come later. I have a number of areas to test concept that certainly carry their own technical risks eg the hoop stress in the little end bush, whether it might extrude out, ring package modifications etc that are all un chartered territory. So I guess at this stage it's one less unknown to stay wet sump for now. As to all the other things, well it will be strap it to the dyno, pull the handle and find out!!

Decision whether to go to a roller cam design or not is still in the balance.. I would like to test that out on an atmo first though ideally.

I assume you've seen the specs of the PRV engined grasstrack racer? Sorry I can't remember who it was (someone well known in CAR circles), but I've got an old C.A.R. Le Journal with it in. Someone will remember, if not I'll dig it out. But a move to dry sump was one of the first things carried out for full on racing.

Good morning!

Had the same thoughts, on this experimental engine not to work with an unproven dry sump system. If all goes well, carefully testing it on the road, log the oilpressure data, then see what is needed and what g-forces the big booty car will achieve. Other point is the cost and work it needs...always a compromise... but i think it will be a pleasure to create one at a later stage.

I assume you've seen the specs of the PRV engined grasstrack racer? Sorry I can't remember who it was (someone well known in CAR circles), but I've got an old C.A.R. Le Journal with it in. Someone will remember, if not I'll dig it out. But a move to dry sump was one of the first things carried out for full on racing.

Hi Darren,

Yes please email it over as I haven't seen the article. It's Kevin Jones from GTO Eng anyway, and it does indeed sport a dry sump. I do have all the hardware to do it, but I think it's a case of making suitable choices and fit to the budget. I would recommend using an Aquasump system (or similar, and do work effectively) to protect the oil gallery from surge oil pick issues as I have suggested to John Law for his circuit application. Indeed as Eddie points out with a good sump baffled etc oil controlled sump arrangement. Kevin did struggle with the oiling system, but he was also turning the engine past 8000 rpm (steel billet crank etc etc). If the car has dual purpose, road and track, then the dry sump is a complete pain in the behind.. But that's just my take on life.. But please do post up or email

Martin

Well you might want to baffle the petrol tank also. Ha ha.

I know, I know, Jil's running a different tank anyway, but the standard one is awful. I had about a quarter (or more) of a tank full the other day, yet still managed to get the engine to hiccup from fuel starvation after a bit of hard(ish) acceleration and a long one in five downhill section with a few curves thrown in.

Short of keeping it brimmed it's a big issue I reckon for anyone serious on tracking theirs. There was an 'interesting' video of a Mclaren F1 in the Alps the other day on Pistonheads. The guys in the car commenting that maybe it was coughing under acceleration because the fuel was a bit low. Aside from the damage that'll do to a catalytic converter, I think some people don't realise the cooling effect that fueling has on the piston and bores. Fuel starvation under high load / revs is a very easy way to ruin an engine.

I'll try to find that article Martin. It hasn't got much detail on the dry-sump arrangement, but Kevin's evolution of the engine is pretty interesting, and it has a few snippets you might like - ported (not polished heads), details of various exhaust manifold breakages etc... don't quote me though, all that's from memory. It must be in the cupboard somewhere.....

.
Thanks Darren, much appreciated. Bring it over sometime, need to catch up anyway, and have those file mods to drop in to your ecu file too don't forget.

Good point about the tank, worthy noting for the hill-climbers out there. Yes JIL is a fuel cell, with just enough capacity for the job. Hopefully pull that thread back to life soon too... Likely get going in a much lower entry spec bizzer first (trying to think of names -for it as a thread title on the lines of it being a bit of a shed)), but that will be another story...

Martin

Will do. I need to get a chance to get the turbo off for you to fabricate that too. It's been pressed into daily use for the past week or so as the BMW was off the road due to a failed MOT - very small lump in the sidewall no doubt caused by a pothole meant a new 200 quid tyre Then that was almost immediately followed by a sticking front caliper. All back to normal I'm glad to say, but the GTA was the workhorse again for while.

Martin,
I,ve been looking at making a sump baffel set for some time...going to fit new bearings to the 24vl...oil press. a bit low on tickover...I have an engine I,ve just rebuilt...not yet fitted the sump...I,ll take a look...on that subject...what was the best oil-pickup strainer you decided on ...after your trials...do you have a part no.
I,m coming over after the new-year... will keep in touch & we can meet up...I,ll bring over a set off rear adjustable A-arms & see what you think.
Worked on both 4cyl & small & big 6 BMW engines when I had the workshop in Maidstone...Guy did some off the head work...they don,t need as much work on the ports as the PRV...just a good smoothing, 3 angle valve seats...I used phospher bronze inlet & SS exhaust...& manifold allightment...could get 100 hp from any engine in the range with a little head work, schrick cam & webbers or my own EFI.
Mid-engine,s a bit slow at the moment as I have to spend a lot off time looking after Carol...but I,ll get back to it next year...the 24vl goes like s..t off a shovel & is still going strong..more mods on the way...just finished cutting the plates for my twin master cylinder brake pedal boxes...will see how that works without servo.
Be in touch soon
Cheers Eddie.

.
Hi Eddie,

Sounds good to me. Is it just the rears you are doing now, fronts at any stage? Peddal box great, I would be interested in that too, possibly 2-off.

BMW stuff ok, thanks, probably easier to chat about it directly. Takes me on to something else, Kugel pumps - mech injection. I want to run one on my track X19. I'm fiddling with EFI all the time, and want to go purist and fancy giving it a go. Have you ever worked on them, set them up? Am I right in that I should be able have a spill control (mech) / by-pass valve and spill off /bleed off fuel as a break point in the fuel delivery curve? If so I should be able to modulate this with an appropriate valve?

Thanks,
Martin