Sam's build thread

[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]

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

[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.

[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

[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

[pogopins]

wow that thing is fast! love the angry noises too

[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