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GT74 High Compression Six Speed


Terminator
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When I get my camera back from being repaired, I will take some shots of what we have done so far.

 

We had a bit of a set back today. Martin finished off the catch tank and fittings on the cam covers today. We then took the car out to begin some serious mapping. Obviously with a high compression engine mapping has to be a little cautious, but a few a few adjustment to timing and fuel maps the car began to feel strong. With a conservative map we got the car to 7000 rpm and to 0.8 bar, waste gate pressure.

 

We took the car back to the workshop to check a few things over, when we opened the bonnet we had an ominous high pitched wine emanating from the cam belt cover. Either the barring in the idler wheel was failing or the tensioner had jammed. Not difficult to fix but so annoying, as things were going so well, better to find it in the workshop, than risk the belt snapping and the terminal results that would cause.

 

The car pulls very hard with little boost, even on a cautious map. We were both really looking forward to pushing the car further. We could both feel how eager turbo was to really get going. I can't wait to get the idler and tensioner replaced.

 

Thanks to Martin, it is all coming together rather well.

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Thanks to Steve Manley at Toyota in Swindon, my new cam belt tensioner and idler pulley should be delivered tomorrow.

 

My project now has an air of conclusion about it, I am thinking of trivial stuff like how to fit my boot amp now the race battery has taken it's place. I am going to the the workshop to night to continue to try and improve air flow from the bumper through the air con rad, oil cooler and radiator, and strip down the front of the engine to make it ready to take the new parts.

 

With a bit of luck we should be mapping again tomorrow evening,seei9ng how much we can get out of the engine at wastegate pressure. I now have access to another camera, so hope to get some clips in and out of the car.

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has steve manley moved to swindon

 

I thought he was based at Toyota Swindon, if not I stand corrected. Anyway where ever he is based, he still does good parts deals, and sounds genuinely interested in my project when ever I speak to him. I'll take him for a spin some day.

 

 

keep the posts coming termy, as i'm building an engine at the moment i am quite warming to the idea of running a bit more compression at the expense of some boost, really interested in the torque graph when you get it

 

I'll do my best, the timing map is key, not having access to any high comp maps, just for comparison, means more cautious mapping. I spoke to Dimitri ages when I first got the motor. He was very confident HC was not a big problem and proceeded to tell me about 2L engines running 11:1 compression, at (I think it was) 1.5 bar. Mapping just takes a little, quite a bit longer.

 

Good luck with the build Paul.

 

Tonight I planned out how the to duct from bumper mouth, to top and bottom of the rad, I think the same method will work on the sides but will require much more template making. I am not 100% sure yet but I may not need to use any stock parts.

Edited by Terminator
Cause I'm daft. (see edit history)
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Fitted the tensioner today. The original idler ,felt just as good as the brand new one, so we left it in place. Rebuilt the front of the car and took it out for a drive. The six speed box is great, the triple plate clutch is fantastic. The power just surges on and on. the sound is amazing. Drove past a pub with at least 40 people stood out side, very single head followed the car. It is a totally different car. The Supra sound has gone, someone said it sounds more like a Lister Storm.:D Going to do some db test tomorrow to see how loud it is.

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Measured two values at 4000 rpm, 30 degrees and 1000 mm from exhaust tip.

 

dbA 95.5 and dbC 108.5.

 

I am not certain, but I believe dbA is the scale used for measuring environmental noise.

 

I'll try to get some fly by shots later, when it cools down.

 

wow, when i first read this i saw 95 dB and thought thats average but then read again and its at 4000 rpm, thats a very good result and yes you are correct dBa is whats used in industrial/environmental

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Everywhere the car goes it turns heads, I have not heard an exhaust like it. If the dbA level is the one that would be measured by track official and other bodies, then the exhaust is not only a visual work of art but a very functional one too.

 

Today I spent about five hours working on the car, at the workshop. Unfortunately due to a minor fuel leak, I did not finish working on the car until the rain came down, not really the best conditions for some spirited driving for video clips. The fuel leak was very minor but filled the car with the whiff of petrol. One of the unions on top of the tank was not as tight as the others. I also got the expansion tank mounted in one of the few spaces left in the bay.

 

The following clip was taken in the work shop, while the heavens opened. The clip was taken from a cold start( 4 hours from last running). The mic on the camera is pretty useless.

 

image

 

For the eagle eyed;

 

One of the vac lines from the waste gate is not connected as we are still working at waste gate pressure and the boost solenoid is yet to be fitted.

 

Yes the filter is held on with tape, we ran out of 4” clips.

 

The expensive sounding rattle is the OS Giken triple plate clutch.

 

At the turbo side of the engine you can just hear a blow on the V band joint at the back of the turbo. This noise disappears after a few minutes after every thing is hot and tight.

 

The catch tank breather is only temporary as we intend running two tanks.

 

The main fuse box is at an angle, it was the only way to get it in, given the intake angle of the plenum and 4” throttle body feed.

 

The wide band probe position is only temporary.

Edited by Terminator (see edit history)
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During last nights mapping session with Martin, we ventured into RPM for which this motor was designed. On the TRD rev counter I clocked 8250 rpm briefly. Quite a mile stone. I still keep changing gear to early, as I forget all the extra rpm there is on tap. The car pulled effortlessly into latter sections of the other dial too.;)

Martin smoothed out and reduced fueling in lower sections of the fuel map making driving around 30mph streets more of a relaxed affair. The higher compression must be playing a significant role as the car is eager at low boost levels, 0.3-0.5bar and off boost completely. Time now for an oil change, ready for the the big numbers.

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The motor was built by VWR, who have an excellent reputation for building high power engines. I went for a spec with plenty of head room. I was advised to limit the RPM to 9000, but being Mr Cautious, I will probably settle for an 8500 limit and probably won't get up there that often.

 

As for power and torque, that is deliberately limited by my injectors. The motor was built to take 1000bhp+ (USA ponies). As for the figures it will achieve only time will tell.

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You may be right about the cams, but at the price I was given them (brand new) it would be rude not to try them. Mid range is not bad due to the near N/A compression ratio I have.

 

We have a few oil cooling issues, nothing bad but want to be safe with a bit more head room, so will be trying to resolve that today.

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Keeping intake temperatures as close to ambient temperatures is always very important. I have several plans to ensure the charge entering the turbo is as close to ambient as possible, including a deflector shield, and if all else fails boxing in the filter so it can not get any hot air.

 

With my current setup, the 9 inch filter is all forward of the stock fan cowl, so I was hoping that the temperature of the air in the feed to the turbo would reasonable. I thought I would do a quick before and after, air intake temperature comparison. I fixed a thermocouple in the centre of the turbo intake tube set up a meter on the dash to monitor. Just before mounting the sensor it was reading ambient air temperatures of 23 degrees. I was very pleasantly surprised to find that during the seven mile journey, which included 30 mph zones with slow corners and junctions and a couple miles of WOT reaching 8300rpm, the intake temperature stayed at 23 degrees. Even with the car sat at idle for a minute the inlet temperatures still did not exceed 25 degrees. I think this just goes to confirm the excellent performance of the stock fan and cowl pushing air towards the back of the bay.

Edited by Terminator (see edit history)
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  • 3 weeks later...

We finally got the car back on the road tonight. The extra work to get charge temps down certainly paid off, we were seeing plenum temps as low as 24/25 on 0.8 bar with ambient around 17/18. So far everything feels very smooth, the car pulls very hard, and the turbo is taking it pretty easy. We have a few minor things to work on tomorrow, before pushing up the boost.

 

AEM 9" filter with new shield in place

image

Edited by Terminator (see edit history)
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