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R34 Gt Engine Advice

Booted34

By Booted34,
in General Automotive Discussion

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Booted34 Apprentice

Booted34

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Hi all!

I'm new to SAU and was interested in some advice. I have a 34 sedan with GTT brakes and suspension fairly well sorted out. In the future I am planning an engine swap. What do people think of an Sr20 instead of rb25t. Why?

To save weight over the front end. To reduce overall weight. To give better power to weight ratio I am not interested in huge power, the car is a daily driver, of course I want more power than what I have.

I know they don't sound as good but I'm not to worried. As I drive on freeways a bit as well as windy roads I was thinking the s15 6 speed. I know its not strong but as I said I am not interested in big power just a nice balanced drive. Any advice is greatly appreciated thanks!

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mad082 Grand Master

mad082

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just stick with the rb25. while the sr20 is a decent motor, it is lacking in torque compared to the rb25. the weight difference isn't that much when you look at power to weight ratios of the entire car. cost wise it's probably a lot cheaper to use the rb25, and i dare say a lot easier to do the conversion. using the 6 speed would also result in you having to change gears more often than the 5 speed, and when sitting on the highway the actual revs it sits on at the speed limit won't be that much different.

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Booted34 Apprentice

Booted34

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Thanks mate! I appreciate your advice. In case you're wondering i was thinking that i would have much more power and tourque than what i currently have with a sr20. You made a good point about trying to keep the conversion simple though. Maybe I should stick with an rb. As for the gearbox I don't mind changing gears and because of the gearing on the car I find myself looking for 6 th often. I guess you can change the diff ratio but then I could miss acceleration. I am thinking of fuel economy too. I thought maybe a vq35 6 speed with the RB? Thanks again!

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mad082 Grand Master

mad082

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Thanks mate! I appreciate your advice. In case you're wondering i was thinking that i would have much more power and tourque than what i currently have with a sr20. You made a good point about trying to keep the conversion simple though. Maybe I should stick with an rb. As for the gearbox I don't mind changing gears and because of the gearing on the car I find myself looking for 6 th often. I guess you can change the diff ratio but then I could miss acceleration. I am thinking of fuel economy too. I thought maybe a vq35 6 speed with the RB? Thanks again!

you seem to be a bit mis-understanding of the 6 speed gearboxes. they haven't simply taken a 5 speed box and added in a taller gear for 6th. what they have actually done is made every gear shorter than the 5 speed. you will find that 5th gear on the 6 speed box is a 1:1 ratio, which is the same as 4th on the 5 speed box, and 6th on the 6 speed box is only about 5% lower than 5th in the 5 speed box. so in reality, if you were at 2500rpm in 5th in the 5 speed, you would only drop down to 2375rpm in 6th in the 6 speed. (that is based off using the same diff ratio)

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Booted34 Apprentice

Booted34

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Thanks I had heard the ratios in a 6 speed were lower. I am planning to change the diff anyway, so I could choose a lower ratio whilst I'm at it. Couldn't that work? Sorry to be a pain at this point I am just keen to improve the car as much as I can whilst I do the conversion.

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mad082 Grand Master

mad082

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i could write another long post pointing out the negatives of using both the SR20 and the 6 speed, but i could be bothered. just stick a rb25det in there and be done with it. a sr20 with 6 speed and taller diff is going to be crap to drive. the r34 is heavier than the s15 so 6th gear isn't going to be that useful. the slightest hill and you'd probably have to either floor it, or drop back a gear.

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Ares180BPM Explorer

Ares180BPM

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Slip light is to let you know wheel slip has been detected and that traction control has kicked in to correct it.

When i changed to an aftermarket ECU the traction control stopped working all together, so i took the bulbs out for both TCS and Slip.

If you haven't changed your ECU, you may want to get a diagnostic done to find the fault code and hopefully get it cleared.

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