Sam's build thread

[sambb]

600hp (300hp per litre) 2.0L 3 cyl, freevalve, twin turbo...….. nuts!!

https://www.roadandtrack.com/new-cars/car-technology/a31451281/koenigsegg-gemera-engine-specs-analysis/

hopefully freevalve will save the IC engine

[sambb]

I was talking with a friend the other night who is building a 3.4L 2JZ Lexus 1s300. The Borg Warner EFR turbo hes using isn't the full motorsporty one, its a rung down from that, but I was surprised when he said that it still ran an internal diverter valve arrangement. Is the idea behind that that the internal DV will be whats used in day to day throttle shut moments but it assumes that you'll still run a BOV ie the BOV be sprung so that it will remain shut for 90% of daily driving but will come into play for harder driving?

[Sydneykid]

I was talking with a friend the other night who is building a 3.4L 2JZ Lexus 1s300. The Borg Warner EFR turbo hes using isn't the full motorsporty one, its a rung down from that, but I was surprised when he said that it still ran an internal diverter valve arrangement. Is the idea behind that that the internal DV will be whats used in day to day throttle shut moments but it assumes that you'll still run a BOV ie the BOV be sprung so that it will remain shut for 90% of daily driving but will come into play for harder driving?

My guess is it has got a DV (in Borg Warner speak a CRV -compressor recirculation valve) so he is using it. DV's are also good for engines with MAF's as the air "stays in the system" so you don't get an excess of fuel when the BOV opens and lets out some air. There is also a claim to less lag with a DV but I can't say as I have experienced it. BW do sell a DV blank off so they recognise that not everyone wants one. My guess, for the "race" turbo it's just a box ticker (yes, tick, it has a DV).

Worth a read http://www.turbos.borgwarner.com/fil...ical_brief.pdf


Cheers
Gary

[pogopins]

Where I'm scratching my head though is how the hell a 7AGE can be in a Barina?!!

IIRC the IPRA engine rules are (a) same number of cylinders and (b) same marque

Holden sold badge-engineered Corollas (Nova) that had A-family engines, and badge-engineered Camrys (Apollo) that had S-family engines

I don't know if any Novas had the wide (G) cylinder heads though! Not sure how naughty that is? And I bet Toyota didn't bother making 4A/7A blocks with the Holden logo stamped in them...

[sambb]

Ah the Nova. That's right. A piece of crap that I'd blocked out of my memory. What a little weapon that car in the vid is.

[Sydneykid]

IIRC the IPRA engine rules are (a) same number of cylinders and (b) same marque

Holden sold badge-engineered Corollas (Nova) that had A-family engines, and badge-engineered Camrys (Apollo) that had S-family engines

I don't know if any Novas had the wide (G) cylinder heads though! Not sure how naughty that is? And I bet Toyota didn't bother making 4A/7A blocks with the Holden logo stamped in them...

Cylinder heads are free in Improved Production.

Cheers
Gary

[sambb]

Gary would something like this be legal under IPRA rules then? Mk1 Golf at Bergen hillclimb. 1400cc VW block with hayabusa head.
https://youtu.be/mSQRoGxRTCk?t=2643

Or this. Same Mk1 or 2 (not sure) VW 9A or KR block destroked to 1170cc and then turbo'd to have equiv capacity under 2L - oh and with a busa head too? Or is changing the induction method to forced from NA disallowed?
http://www.werace.tv/hillclimb-monsters/400hp-vw-golf-mk2-1-2l-turbo-11-000rpm-hayabusa-engine-head-swap

[pogopins]

wow that thing is fast! love the angry noises too

[Sydneykid]

Gary would something like this be legal under IPRA rules then? Mk1 Golf at Bergen hillclimb. 1400cc VW block with hayabusa head.
https://youtu.be/mSQRoGxRTCk?t=2643

Or this. Same Mk1 or 2 (not sure) VW 9A or KR block destroked to 1170cc and then turbo'd to have equiv capacity under 2L - oh and with a busa head too? Or is changing the induction method to forced from NA disallowed?

MK1 is prior to 1/1/1986 so OK to turbo. Post 1/1/1986 has to be turbo originally.
Cylinder heads are free, so no issue with using a hayabusa head.
A 36 mm restrictor is mandatory for the MK1 weight, which will limit it to around 400 bhp. With the right spec turbo and ~10,000 rpm it should be capable of that easily.
FWIW, the capacity limits in IP are +2%, so 2040 cc's is OK, / 1.7 = 1200 cc's.

Cheers
Gary

[sambb]

Ok. Has anyone ever gone to that extreme in IPRA or aside from budget constraints is it more a case of not wanting to be that guy that's so far outside of the spirit of the rules?

[Sydneykid]

Ok. Has anyone ever gone to that extreme in IPRA or aside from budget constraints is it more a case of not wanting to be that guy that's so far outside of the spirit of the rules?

Simon Philips from Vic has Datto 1200 Coupe turbo for U2L, it uses highly modified A Series engine, Jordan drove it at the 2018 Tailem Bend Nationals. It's power to weight is pretty effective being a light chassis but the rpm limit of the pushrod valve train is a bit limiting. When it was N/A he dabbled with a Honda CB 1000/1100/1300 cylinder head, which would fix the valve train issues and let it rev to what it could do. It's big advantage over the N/A U2L is of course torque, at 21 psi it would have ~50% more torque than the best N/A engine.

A couple of guys have had a go at turbo Mk1 Suzuki Swifts (they are pre 1986), just destroke them to 1200. But getting a transaxle in them to handle the torque is not easy. Plus cooling system, driveshafts, uprights, etc makes it an expensive exercise, with pretty much everything being bespoke. Compared to the off shelf gear for Hondas, Nissans, Toyotas etc. Someone with the time and budget will do it eventually, but it will require patience and lots of engineering effort.

Cheers
Gary

[sambb]

yeah ok. sounds like a mega undertaking to motorcyce head a car block. I know that the same capacity reduction thing has been done with 1.8 blocks with my engines head to get it down to 1200cc to fit into the under 2 L class. No idea if they sleeve them too but they'd have to be destroking which would need a whole new crank yeah. Its already well undersquare so they'd have to do it that way to get it down to 1.2 surely.

[sambb]

Gary, wondering if I could pic your brain RE inlet manifold design. For now I'm pretty much stuck with the single throttle system as my tuning happens via the stock ECU so I think a quad throttle arrangement is a way off.
The large port AGU inlet manifold that I have for when I do the rebuild is an ugly work of fart - huge 'dents' in it to accommodate the alternator and dipstick and a weird throttle body angle that points the plate at cyl 1 and runs the air along the roof of the plenum which looks to be just a packaging compromise rather than a design aim.
So say I was to cut clean off and leave the runners onto their base plate, I was looking to do a barrel plenum welded onto that. sort of like the pic below:

That constrains me to the same runner length but should result in a better throttle body angle and uniform plenum - I hope. I'm thinking it'd be best to retain also the length from runner flange at the head to back wall of the factory plenum in case helmhotz tuning was something they'd put a bit of effort into. But I can adjust total plenum volume this way. Ive seen it written that plenum volume should be 80% of the swept volume of the engine which in my car would be 80% of 1.8L = 1.4L. Does that hold true for forced induction cars?
Also I remember you saying that a smaller plenum boosts response which is a biggn' for me. At the time you were talking about quad throttles though so I was wondering if that also holds true for single throttle bodies? ie would I aim to go no more than 1.4L plenum and then offset down from there to get a more responsive setup.
would be stock throttle body, and as you know a golf 6 gti turbo with breathing mods + tune.

Other option would be to also just cut off the smaller Polo plenum and weld that to the large port runners, as the polo mani has a direct side feed throttle body position and a less curvaceous dented plenum simply because it is smaller.



any help massively appreciated. My back has given out so I need some bench work to go on with at the moment.

thx

[Sydneykid]

The inlet plenums that have worked best for me taper towards the last cylinder (eg; Pulsar GTiR), this evens out the airflow so the last cylinder doesn't get the most air.



Even then, when we are tuning we find we need to add a bit more fuel to the last cylinder/s (particularly on an inline 6) as they still get a bit more air than the earlier cylinders.

The total amount of air between the inlet valves (IV) and the throttle body (TB) is what affects the instantaneous throttle response. Obviously when we close the throttle we get a partial vacuum behind it which has to be filled when the throttle is opened. That's why the really responsive turbo cars run ITB's (much smaller distance between the TB and the IV).

The overall objective is to keep the volume between the single TB and the IV's as small as possible but not so small as it invokes turbulence in the inlet port. I would treat the 80% (of engine capacity) rule of thumb as the maximum, that's from TB to IV's, not just the plenum itself. Making the inlet runners a little longer and the plenum a little smaller will help in reducing the port turbulence.

Then you have to fit it all into the available space, which generally compromises the "ideal" design. But who cares, just add 0.1 psi of extra boost to compensate.

Cheers
Gary

[sambb]

That's unreal info Gary. I'll start filling my 3 different 1.8T 20V manis with water to see where they all sit relative to one another and build a plan.
I'll also let my 2JZ mate know. He's bent on a plazmaman mani but I'm not sure if they have more of a drag strip motivation to their volumes rather than hillclimb/circuit.

thanks