Reply With QuoteWith higher revving at cruise it's probably the better choice. Just make sure you have a good strong driveline.Originally Posted by Jitterbug
Master
It is ordered now so I am committed haha!
Flagg's good results and my evo/skyline/silvia rice burner friends singing the praises of the EFRs all helped convince me, plus I have 4.11 r&ps and 33" tyres so will be revving about 10% higher than the 4x4 isuzus 110s on stock tyres.
ForumSage
With higher revving at cruise it's probably the better choice. Just make sure you have a good strong driveline.
Master
It is about as strong as it can get staying with rover
Rebuit LT95 with TRB (and a couple of other mods)
ARB centres
Ashcroft R&P
Hi-tough axles and flanges.
we will see how it holds out...
YarnMaster
Subscriber
yeah I get boost from nothing so don't worry about lack of low end with the 6258 - other may have more but you won't be lacking.
Hercules: 1986 110 Isuzu 3.9 (4BD1-T)
Brutus: 1969 109 ExMil 2a FFT (loved and lost)
ForumSage
With any of these turbos you'll get small amounts of boost building from idle. Just some will build higher numbers.
Having the boost build slower with rpm is a good thing for gearbox longevity. A few hundred more rpm makes it a lot smoother.
ForumSage
I've got another hare-brained scheme. I've just bought a TD04HL-19T compressor wheel and I'll see if I can fit it into my T25.
The reasoning is pretty simple. It's a stop-gap measure that'll give me better top end than the T25 wheel, won't surge like the T28 wheel did and it's less work to fit a compressor wheel in (machine out a housing to suit) than it is to make a new dump pipe, compressor outlet, compressor inlet and oil feed/drain lines.
I have enough T25 parts to make a bolt-in and just swap it.
The downsides compared to using a whole turbo.
My T25 turbine isn't as efficient, so boost will built a bit slower (but should still see ~23psi by 2000rpm) and drive pressure will be a bit higher (but should still produce drive pressure below boost from ~1500-2500rpm under full load).
The 19T compressor wheel according to the maps is more efficient right across the range I use than the T25 wheel. But this may be offset by putting it into a housing that isn't matched.
The big unknowns?
1. The shaft bore is different, we'll see how I go drilling that out.
2. The wheel OD is different, we'll see how I go machining out the bearing housing to suit.
3. The amount of offset in the back of the wheel is unknown.
4. The tip width compared to the T25 is unknown.
I'll have a measure-up when the new wheel arrives and see how it looks.
Wizard
And you bale up at redesigning a TC
ForumSage
Turbos are a lot more fun to test drive. I could spend all that time on making a transfer-case into a different shape and it would drive exactly the same.And you bale up at redesigning a TC
Wizard
Can`t argue with that but one could be noisy the other exy
ForumSage
I got my Air/Fuel gauge wired up and clamped onto the end of the exhaust. The results were very interesting.
I run a max sustained EGT (at the moment) of 750C. So pulling a decent hill in 5th gear at 2000rpm pins the needle right at 750C.
My A/F ratio right here is 20:1 and this is consistent from the moment the turbo has spooled up until it hits the governors.
It's hard to spot, but I get a slight dip to ~15:1 as the boost compensator opens fully by about 7psi and a small puff of smoke before I get the boost to burn that.
At 100km/h cruise (9psi boost) I get an A/F ratio of 35:1. But this was on a short run. I think it'll settle out to slightly higher on a longer run when everything is up to temperature.
So, for those running ~20psi with no intercooler, you're always going to hit EGT limits before you hit smoke limits.
Even with a decent intercooler I expect you'll hit EGT limits before you start smoking under load.
Which means. Those who are smoking at full power will be somewhere around 900C EGT.
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