IRP Q45 Differential kit review
 

IRP Q45 differential in FD kit.

I contacted IRP earlier last year about a Q45 R200 style differential as an alternative for the Cobra Diff due to cost. He had his team fabricate a kit and I've been going back and forth with him. I told him I would test it out at TX2K16, my car puts down over 800rwhp and 600ft-lbs on the dyno the night before TX2K. I drove the car 1100 miles, ran it hard on the streets without any issues.

The kit he supplied me came with the hy-tuff half shafts, chromoly differential brace, and delrin bushings and all the hardware. This kit could be bolted on without any welding. It was straight forward to put on. The kit is great for guys that do swaps or looking for a way around the stock differential. I will post pictures of the kit later this weekend. I would like IRP for their time in developing a kit that is affordable for our community.
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That's sweet! Sounds like a really good alternative.

Dalle

Yep one of the many projects we are working on. Hope to have this available to the public in a couple months. My goal is to have this come out to cheaper than the cobra rear end swap. Here are some pics of the prototype mounted in the car.

Nice. That's a good diff. I have one on a 800whp 2jz. It has more torque than most rotaries.

Yes it is pretty stout. The above car has a 2jz swap so it is making more torque than a rotary ever will.

im interested in this... i have a 2jz fd as well. taking it easy right now so i dont blow my diff up. cars making 620tq

This would definitely work well for you.

I was in the same situation and didn't want to go with the Cobra Rear end. It seemed way overpriced for what I needed. I couldn't go out and push the car without worrying if it would get me home or being towed home due to the weak factory differential. With the Q45 differentials being very affordable and just mounting a few things I was able to install it over the weekend.

nvm

these are open diffs from the factory no? what are you using as upgrade? Btw, I can't edit or delete that^^

Pretty sure it is VLSD on all Q45's.

The same diff is also in a few other cars (na 300zx), but mounting points and output shafts vary.

Interesting. What ratios are available?

I got curious so I went and checked the shop manuals and this is the info I found:

1991 to 2001 are R200V VLSD

2002 to 2006 are R200 Open


Nissan also has R230 open units on some V8 SUVs which are even stronger.

A lot of people swap their Viscous units for clutch-type or helical because the viscous torque transfer is low and tends to go open diff when heated up at the track or drags.

I assume some tall ratios are available like with the Ford 8.8 if people are running this for the Texas Mile. Not sure if that exactly answers your question or not as I have no info. You could always call IRP and ask. I guess know the pricing might be a cool nugget to find out as well. I'm sure that's being worked out but I'm Nosey.

Well I'm looking to stay 4.10 or go up to 4.30. The T56 I have is close ratio and perfect for my NA 20B. I will also eventually turbo charge so I wouldn't mind upgrading now.