turbos and high revs
Turbo Mini Forums

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

well , I'm a bit disapointed that my help has not been seen. sorry steve but hybrids doesn't mean anything now, it was with the olds t2/t3 t4 stuff, but doesn't have to be concidered now. a top turbo is a garrett gt20 and all the same sized kkk, ihi and mitsu they're all spooling from nowhere and makes high efficiency.
Really what is needed is to know how many boost you'll need and how much power you want.regarding myself 9000 rpm with 18 psi will sort some very big numbers (around260/280), what's involved is to spoll this turbo at lower revs(bb titane vnt etc will have to be concidered)

The vehicle is loaded with nitrous, but I'm not so sure about how the drivetrain (especially the rear diff) will hold together with 9000rpm, 18psi and gas....

I (personally) feel that low boost from a responsive turbo, such that the engine specs change little, and it can spool up easilly is the route to go for this twin-engined, nitrous assisted, highly strung drag racer.

I also think that a low boost set up is the way to go (it will retain high cr,so can use a long cam), but about the turbo I would use a slightly larger unit that is needed (with this the tip will allway be less than intake) to clear the combustion chamber from exhaust contamination and so you'll also not have to use a larger lsa cam,perhaps the one you already have...
what could also be determinant is exhaust pulse separation mainly because a long cam will make to much pulse coming in the same place at the same time, so a divided housing with the proper manifolding will certainly worth the job.

I'm not sure I've seen (apart from the IHI unis on the latest subaru's - and good luck trying to find a compressor map for them) divided housings on any of the 'smaller' turbo's?

Natually - I'm well aware that if anyone will know, it is 'mr turbo' himself - ie Fab :)

The toyota CT turbos have 180 split turbine housings, some have caramic turbine wheels too AFAIK.

Also ive got to agree with fab about the t2/3/4 being out of date, its a design that dates back to the 70's. So much more has come from urbine design since then that they can run up to 10% more efficient over a larger flow range.

With a high RPM engine you can allow for a larger turbo, although it will spool up later the 'active' rpm range will be the same as a normal RPM smaller turbo engine.

Im going for a VNT22 on my imp, thats a 930cc 8 port engine, and 7500 - 8000rpm redline. The Vnt should allow me to come on boost earlier with less restriction at the top end.

Cheers

J

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

weird...double post

Edited by stevieturbo on 3rd Nov, 2006.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

the ihi used on subarus are bomb proof......
titanium, twin scroll, ball bearings
in my head it start like "I had a dream that one day........" ouarff
well their is two different sub tit twin scroll the imp and also the legacy one, the small one (legacy) have a 390 max cfm comp, ihi having 12/18% surge line mean that it is over flowing my engine which I have to prevent from gearbox destruction (having to stay with helicals)....
but that it would be a must for your(you'll go in the end of high efficiency map at 300cfm ie 200 bhp), if you want one their is an ebayshop that oftenly have some resonably priced for sale it's: warehousejapan

Loads of maps bottom of here

http://www.rbracing-rsr.com/turbotech.html

Metro turbo weekend driver,Mini turbo in the making again!

Seen that warehousejapan place on ebay...

I was a little cautious, in case they are chinese fakes or something.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

chinese fakes???I wouldn't have put an input for this, this is a very good link and place .They are japan shop !! the patry of ihi and mhi and it's just what they are saling....I've just seen a vf38 for 180 bucks...

and sorry for my misunderstanding of your t3 t4 flanged stuf, clearly we have the same point on gt and late mhi stuf

Dave about smaller twinscroll, they 're is also mhi twin scrolled td04 used on volvo v 40 165 and 200 bhp trim (tdo4-12t and 14 t respectively) and also renault f4rt last engines also in 165 and 225 bhp..but here no titan or ball bearing :(
fab

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

no I haven't already bought from them myself but he's known in subaru comunity, I keep an eye from them for some time as they have sold in the past ball bearings rhf4b which would have a been a great turbo for my de tomaso turbo...so know that what they have sold had completely satisfied their customers by feedback.

woof fab ,do you mean a pantera !!!!!!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

no it was an innocenti de tomaso turbo (the square mini with 5 speed and 3 cyl jap engine), it's a lot more lively :) in Paris ( I boosted it with 1.4 bars a big intercooler, n/a cams, vnt15, it was regulary took 8500 rpms in a semi porsche brooooooooob) I really sometimes miss her
even if a pantera would have made a lot of effect

I had a Daihatsu GTti, those three cylinder turbos sound ace, half porsche and half skyline! Mine was making 147bhp, pretty liveley as you say

J

So, back to the thing about high revs. That's one way of doing it. One thing I had a think about was whether to waste money on some bowley pistons or a secondhand stroked crank, something like an 86mm (1460 with 73.5 pistons). Since the BMW head flows so bloody well, it could obviously flow to a much larger capacity. If you think about a standard S Head, IIRC, it only has the right flow for the job of a 970 (according to Vizard) so any hikes are likely to produce cumulatively less power. With the BMW head, it's got to produce the right gains. So, not thinking about using less than 73.5mm bore but it may be possible, what size does the bore have to be in order to clear the rods? If you were to up the capacity and have a crank safe to 8000 say (which should be fine from a fresh forging forging) with that extra capacity and leverage, I'd say that would probably pay off more with such a head. One thing though, I was looking at the exhaust flow figures for the BMW head and they are pretty good but not amazing, obviously with a bigger capacity and boost/nitrous load, this would perhaps start to show this as the weaker link? I had a think about this and reckoned I've found a solution. Not wanting to go to the level of having cams ground (jeez, so little money, so much to do with it) I figured on using an LT inlet cam with an RS exhaust cam, that should be tweakable to a power band of about 1500 to 7000 on about a 1380 if my hunch is in the right ballpark. Another thought, I have lined up an RS head with a chap up the road and my mate has an LT head (the £350 one) Therefore 2 sets of right cams for the job! I'm wondering what peak pressures you would be dealing with and what the setup could handle.

One thing I'd like to know more about is how the pressure of a blown engine varies with crank angle with different boosts and strokes. My initial thoughts are that stroking it is a good idea.

Just some thoughts......

Stu

Mini currently off the road with an A+ 1380 with 11cc pistons waiting to recieve a new gearbox (havent bought yet GRRRR) and the BMW head, will give it a little bit of boost from the M45.

Need some cam extensions though.

Bugger off, I'm getting there.

Stick with the twin engines carl, that's what makes your car special.

However, Peter has made a good point in that the two engines play a very different role in the course of a quarter mile.

The front engine has very little grip at the start and just spins the wheels, whereas the rear engine bogs down off cam due to the huge weight transfer and grip.

Didn't you say in another post that your rear engine is not making the power compared to the front - maybe just down to your perception of the relative revs due to the difference in grip.

I think you should seriously consider two very different setups for each engine.

High torque, low revs and small turbo at the rear and all out horsepower, high revs and big turbo at the front.

Use the torque at the rear for the launch and the horsepower at the front for the trap speed.

Bollocks or what?

Edited by Paul S on 6th Nov, 2006.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

2 mildly tuned, very responsive turbo engines, with a taller diff, would perform superbly.

IMO forcing it to rev to circa 9000rpm is pointless.
I know that my car would pull 7500rpm on a flat in 4th with 165/65x13's and a 3.1 diff. It didnt even take a huge distance t do it either. 7000rpm came up pretty damn quick.

So imagine 2 engines like that in a Mini. If you can reach those sort of speeds in the 1/4, then you are bloody flying !!!!!

Having sensible sized turbos, will make launching it a doddle too, as lag shouldnt be a concern at all.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I thought I said something similar on the first page!lol!

Carl - figs to follow soon

If Carling made Mini engines
it would probably be like this one!

bigger wheels?

Maybe then you'll start making some lighweight 13" rims Carl....

Fastest 998 mini in the world? 13.05 1/4 mile 106mph