not intended as a personal attack phunkdokta. I'm sure I haven't upset you have I? I'm flatter if I did, cause barpk couldn't manage it --just kidding-- All of what you have said in here is right, and you obviously know what you're doing. I just think there's a better way. Don't close your mind to the possibility.

You have described the limitations in detail yourself; amount of boost limited by the amout of fuel pressure you can achieve and control, and also limited by what the carb or box seals and float can withstand.

The real drawback of the draw through carby system is that you can't really intercool it. Most of the unlimited category speedboats run drawthrough carby turbo V8's with intercoolers, but it obviously only takes one backfire to turn them into a bomb. But there are ways around that, up to a point.

true EFI is the ultimate for performance, driveability, fuel economy and reliability. But for most people like you and me, the cost of the ECU and tuning is still prohibitive. I'm still after the maximum performance I get get out of what I can afford to do.

Besides, it's much more fun doing it all yourself. I'm sure you and I are really on the same wavelength on that score. Hell, the more fast little 1200's out there the better! "To each their own" is fine by me, just offering my perspective.

Harry

Thought I'd let you guys know how the couple of Datsun 1200's that were competing went at the QSSS Final.

There was over 160 cars registered for QLD Super Sprint Series making it the biggest Sprint Series in Australia. These cars were split into two separate qualifying series', A and B. The top cars from each series came together last weekend for the Final to determine the QLD Champions for each class. The format for the final was a standing start, 4 lap, multi car sprint.

Improved Production 0-1600cc
won by Craig Allen in an A14 powered 1200 coupe. 2nd place went to his father Malcom in the same car. It has about 108 bhp at the wheels, and although not as fast as mine in a straight line, it handles and stops significantly better due to the lighter weight and the huge track. It must be a foot wider than mine! They both peddle the little thing pretty damn well too. It's great to see it rounding up some of the more fancied and much more powerful LJ/LC toranas, and keeping right on the heels of 13B powered RX7's etc

Improved Production 1601-2000cc
won by the insanely fast 16v twin cam Escort of Gavin Wilkinson. (Also currently leading Imp Prod circuit racing State Championships, and finished 2nd in the previous weekend's Imp Prod National at QLD Raceway) I finished 3rd by 0.48 seconds to Frederick's 2l Gemini. That's 0.48 seconds over 4 laps, so it was pretty close.

I made a few suspension changes since my last outing and was on a different type of tyre as well. So my first run was just a bit of a 'sighter' to get the feel for the car and the tyres. That run turned out to be as fast as I had ever gone in any of the qualifying rounds through the year! So I was very happy and looking forward to a good dice with Chris Berry's 1600 for 2nd place. I knew I had no chance of catching Wilko's Escort based on the times he posted over the course of the year. But I had beaten the Gemini before, and with the improvements made to my car, I was confident that I had his measure for the weekend.

Chris (1600) stripped the teeth of the oil pump and dissy driveshaft and failed to post a time for the weekend. He loaded the car on the trailer and went home to prepare for next weekend's Noosa Hillclimb. So I thought I'd be pretty comfortable in 2nd place, but on the 1st lap of my second run it jammed in 3rd gear coming out of Turn 3, a fast left hand sweeper which leads onto the back straight. So I held it at about 8000rpm in third all the way up the back straight. Couldn't get it out of gear for the downshift to 2nd for the hairpin at the end of the straight, so I lost more time through that corner and the following esses with the engine off the cam. Managed to finally get it out of gear on the main straight - I wasn't exactly being gentle with it by that stage! But from then on it was pretty difficult to persuade it to downshift, even when paying extra attention to rev matching and heel and toeing.

Anyway to cut a long story short, although it never jammed in gear again and it somehow managed to hold together for the whole weekend (7 runs), I never managed to go faster than that first sighting run due to the baulkiness of the downshifting in particular. Instead of simply heel/toe downshifting under brakes and focusing on your line and entry speed, your had to fight all the time just to get that gear, and sometimes you simply couldn't get it in untill much later than you needed, and you should have been back on the throttle to balance the car throught the corner. Even so, it took the Gemini 4 runs to beat that time I set on my first run, and I finished the weekend comfortably in third ahead of the rest of the cars that made it to the final in my class. It was pretty frustrating, but at least i came away with something, and I was very happy with the improvements in the handling. Hell, it was worth the trip just to see some of the other cars that were there, and for the piss-up on Saturday night...

I've arranged for a loan gearbox for the remaining 2 events this year, Noosa 16-17/11, and Mt Cotton Hillclimb Dec 1. Now all I have to do is change the bloody thing one night this week.

Jeez, I just hit 'Preveiw'. That's alot longer than I planned. Sorry but now that I've written all that it would be a waste not to post it!

the "saturday night special" comment was very tongue in cheek...

ahh I see what you mean now, dissconnect the wastegate actuator ROD so that the wastegate is free to open all the time. Rather than disconnecting the wastegate actuator from the compressor housing!

Fuel pooling is not a problem when the compressor wheel is actually being driven. You may get some wetting of the manifolding after the turbo, but I never saw any evidence of pooling in the compressor housing on my motor.

Back to the actual point of blow through vs draw through...
Personally, I prefer the simpler and cheaper draw through system. And from an engineering perspective, the best solution is the one that does the job effectively with the least complexity and minimal number of additional components. Not only does the draw through system have fewer components and less unnecesary complexity, it also does not suffer from the limitations of the blow through system. Extra capability from a cheaper simpler system - No contest really.

yeah, your system would be quicker to change. the point I was making was that with a draw through system using a downdraught Weber instead of a better sidedraught Weber or SU, and the standard inlet manifold instead of a better fabricated item would give you that option albeit at the expense of a bit of power. It wasn't supposed to be a benefit of draw through over blow through, but I can see how you interpreted it that way. let's not make this thread any more agro than it already is

45 minutes is an outside estimate. I could put up with that. Some of the racetracks I compete at are 2.5 hours drive away and undoing a couple of pipes and moving the carb is a small price to pay to avoid having to tow the car home if you happen to blow the turbo at one of those events.

Quote: how about you try that and see what happens! I think you're in for a surprise...

as for your suggestion of sucking the fuel through the turbo when running in aspirated form, I reckon it would be very sluggish and horrible to drive. You would also have problems with pooling of fuel in the compressor housing which would't be a very good idea when you connect it back up - liquids don't compress very well

[quote="Dragongoose"]Sorry guys, I still prefer the suck through carby setup...the standard mechanical fuel pump which should handle it real well. Power with a t25 garrett should be around 180 Hp at the fly wheel on conservative boost say 8-12 pounds...don't need a Blow off valve as there is no throttle body in the way. So simple effective and practical, and it looks real cool seeing the carbys hanging off the turbo inlet. Better than looking at a box.

some of the info I have seen here is dubvious, one thing I have read I know to be wrong, and another thing I saw is downright dangerous.

Calipers
you should never use a caliper intended for a vented disc on a solid disc. EVER. The thinner solid disc COULD allow the pads to literally FALL OUT when they wear down, but definitely WILL reach a point where they fail to clamp the disc, before the pad is worn out.
If you really can't stop yourself from doing this, you should at the very least manufacture 4 equal sized spacers to the shape of the pad's backing plate, and fit them in the caliper behind each pad to allow for the thinner disc.

Remember it is not only your life in your hands when you mess with your brake system. If you are not 100% sure about what you are doing, don't do it.

Spring sizes
240Z definitely have the smaller spring seat. beleive me. same size as the 260Z, 1200, stanza, etc

I think the coupes have the twin spot sumitomos and the sedans just have a single piston slider type caliper. But yeah, just look for the twin spot calipers.

They fit under 13" wheels.

the 240K struts will fit onto the stanza lower control arm (the 240K lower control arm is much longer than the Stanza - probably too long to use in a 1200. I will measure them later). They haver the larger spring seat, which will need to be removed and replaced with Stanza/1200 spring seat (or 60mm coils and adjustable platforms ). The 1200 strut tops fit. I will be able to tell you more about any possible camber change and any difficulties with brake lines or caliper clearance when I have a closer look at the struts. You may need a larger master cylinder to cope with the twin spot caliper as well (I assume you are talking about the twin spot sumitomo 240K brakes). The 240K strut is much shorter than the Stanza strut, which is a good thing - means more suspension travel is available which is important when lowering.

The strut length is the biggest drawback of the Stanza strut conversion - it will limit your suspension travel on a lowered car. The Stanza strut has the longest body of any of the struts I have (see earlier post)

the 200B Girlock caliper is identical to the Stanza Girlock caliper. I use the larger Commodore pads in these with some very minor grinding of the pad backing plates. Lots of good pads available for Commodores

I'm trying to sort out which struts I'll use next year as brakes are the 'weak link' on my car at the moment

I can check some of the info for you. I have MR30 Skyline, C110 Skyline (240K) twin spots, 240Z, and Stanza struts and brakes in the shed. And my road car is an R31 Skyline so I can check them too. But I'm racing this weekend in the QLD Super Sprint Series Final, then Noosa Historic Hillclimb the following weekend (hopefully - haven't got confirmation that my entry was accepted yet). So between racing and preparation work on the car, it will be a couple of weeks before I really have time to dig these struts out and compare them.

I noticed in a topic a bit further back someone said 240/260Z struts will fit on the Stanza lower control arm/balljoint. This is NOT true. The bolt spacing at the bottom of the Z strut (where it attached to the steering arm) is wider apart than every other common Datsun strut that we are talking about here. You will need to get either the steering arm or steering arm and balljoint or complete lower control arm. I have not confirmed which of these options is best yet, I have to go and have a closer look at what exactly is the best way to go, then buy the peices so I can use my 260Z struts and brakes. Safest bet is to buy the complete strut, brake, and lower control arm assembly and you can be sure you have everything you'll need to complete the conversion.

yeah, it's a simple case of drilling 4 holes at the front and four at the rear to mount it to the bootlid.