Twin-screw anyone?
Junior Member
Joined: Apr 2018
Posts: 12
Likes: 1
From: Mallorca
Bump!
I'm in the process of negotiating to purchase a 2002 XJR 4.0 and seriously considering a twin screw upgrade.
I have only recently joined this forum and can't seem to send private messages.
Is there anyone else out there wanting to do a twin-screw install?
AVos, what exactly was included in your kit?
I'm in the process of negotiating to purchase a 2002 XJR 4.0 and seriously considering a twin screw upgrade.
I have only recently joined this forum and can't seem to send private messages.
Is there anyone else out there wanting to do a twin-screw install?
AVos, what exactly was included in your kit?
Thread Starter
|
Veteran Member
Joined: Apr 2008
Posts: 3,616
Likes: 1,070
From: Europe
Here is a nice write-up, you will also see some pictures:
https://www.jaguarforums.com/forum/x...kit-usa-82598/
https://www.jaguarforums.com/forum/x...kit-usa-82598/
Junior Member
Joined: Jun 2018
Posts: 3
Likes: 0
From: San Francisco
Here is a nice write-up, you will also see some pictures:
https://www.jaguarforums.com/forum/x...kit-usa-82598/
https://www.jaguarforums.com/forum/x...kit-usa-82598/
Member
Joined: Aug 2017
Posts: 76
Likes: 11
From: Philadelphia, PA
I have been constantly researching how to do this to my STR, currently spent a lot of money on it but i do plan to do this soon if it is within a strict budget and capable of DIY. I have to replace my supercharger soon anyways. The end goal is KB supercharger, LSD, and other goodies such as cooling mods and lighter components
If anyone could be of any help I would be extremely grateful. Thank you.
If anyone could be of any help I would be extremely grateful. Thank you.
Senior Member
Joined: Aug 2020
Posts: 208
Likes: 134
From: Vancouver
''I did not do the work myself, so the costs are initially higher. Had I chosen to do the installation myself, it would have taken longer and I would have had to hire help. It also may not have run properly.
All of these things depend upon options and choices. I will keep AVos' supercharger kit price private because his kit is also dependent upon choices and I can't quote a price for him as an agent. His kit price is lumped in with other things. Taxes and shipping are thrown in as well. Prices are approximations. These approximate prices are for an engine swap and supercharger installation.
4.2 Engine with 42,000 miles:$4995 (+shipping)
Supercharger kit, related parts, intake, supporting hardware and other goodies (odds and ends): approximately $7000-8000
Installation (not including differential): $10,450 (lots of engine parts in that price, too)
Preparation for install by techs: (no cost, because they were nice)
Total: $22,445 - $23,445 (added without my receipts next to me, so there could be another $1000 missing somewhere)''
Junior Member
Joined: Nov 2020
Posts: 4
Likes: 0
As some of you know I have quit making twin-screw kits last year for several reasons (not related to the kit itself). An owner of one of my kits asked if I could make another one, that in combination with my situation that allows it to do I have decided to make a last batch of the XKR/XJR twin-screw kits.
But now for you here, I have the ability to also make some 2.1L Twin-screw kits for the 4.2 STR, 4.2 XJR and possibly the 4.2 XF.
The 2.1L kits are not the same as the 2.6L I have made, but these still provide a very good power level pending on other mods, somewhere in the 450 rwhp, or a good 500 engine hp to be on the safe side, and possibly more importantly it is at a much lower cost than the 2.6L kits.
Please contact me if you are interested in a kit like this, I would need to know within 2 to 3 weeks in order to combine the orders and keep the costs low, and this is a one off!
But now for you here, I have the ability to also make some 2.1L Twin-screw kits for the 4.2 STR, 4.2 XJR and possibly the 4.2 XF.
The 2.1L kits are not the same as the 2.6L I have made, but these still provide a very good power level pending on other mods, somewhere in the 450 rwhp, or a good 500 engine hp to be on the safe side, and possibly more importantly it is at a much lower cost than the 2.6L kits.
Please contact me if you are interested in a kit like this, I would need to know within 2 to 3 weeks in order to combine the orders and keep the costs low, and this is a one off!
Veteran Member
Joined: May 2009
Posts: 12,094
Likes: 3,368
From: home
Just remember that your 4.2L sport has higher compression than the STR and has not been upgraded internally for FI. You would be far better off to sell your car and get a STR. Even if you want Avos's kit.
.
.
.
.
.
.
Junior Member
Joined: Nov 2020
Posts: 4
Likes: 0
Are you still doing the 2.1 set up
Senior Member
Joined: Jul 2013
Posts: 422
Likes: 106
From: Wales, United Kingdom
Whilst I am not the supercharging expert avos is, I am able to re-make the 2.1 KB kit which avos used to offer and have ran various iterations of twin screw superchargers for around 8 years.
I was able to take a careful look at a 2.1 KB kit supplied by avos and take all relevant measurements in order to reproduce a slightly improved version, with a better finish than the hand-made versions avos made many years ago.
For background, I initially bought a 1.7 Opcon Autorotor from avos around 8 years ago, which I understand made around 380rwhp on his 4.0 XKR (up from a stock 320rwhp). On my 4.2 STR, it made just over 400rwhp with a 2.5" upper pulley. After switching to a 2.16" upper pulley, I was able to achieve around 430rwhp. This was on an essentially otherwise stock car and the power delivery was transformed, even though the way that the 1.7 was adapted was very poor and blocked a lot of airflow. I ran this 1.7 supercharger for many thousands of miles without issue, and as far as I know it remains happily in use in New Zealand with another forum member.
As avos stated in his original post, the 2.1KB is better again than the 1.7 and can comfortably make 450rwhp on our engines. I have mounted the 2.1 KB further forward than avos and was therefore able to optimise the inlet further, achieving virtually unrestricted airflow into the supercharger. I have already put mileage on my kit and tested it under various conditions without any issues, and it has performed even better than the 1.7KB (with which I previously achieved 430rwhp). I estimate with a smaller pulley that 500rwhp will be achievable with the 2.1 KB, and this reportedly already has been achieved on a STR using a ported TB, larger aftermarket MAF and tune.
I am able to re-make these kits for the STR/XJR, which I understand would also fit the SV8 (although I do think the kit would make much more power here and on the X358 XJR). I am currently now working on the X308 XJR and X100 XKR kits, which should be completed this month. If anyone is interested in a kit, please feel free to PM me. The way I have designed the kit means that it is entirely bolt on and reversible, so it can be installed by any DIY mechanic at home.
N.B. If desired, I could in theory make the kit with a 2.6H (or even 2.8 or 3.0 KB) and relocated TB like avos innovatively designed, however in my opinion the 2.1 KB is the best compromise for cost and ease of installation. It also sounds incredible and is louder than the larger units!
I was able to take a careful look at a 2.1 KB kit supplied by avos and take all relevant measurements in order to reproduce a slightly improved version, with a better finish than the hand-made versions avos made many years ago.
For background, I initially bought a 1.7 Opcon Autorotor from avos around 8 years ago, which I understand made around 380rwhp on his 4.0 XKR (up from a stock 320rwhp). On my 4.2 STR, it made just over 400rwhp with a 2.5" upper pulley. After switching to a 2.16" upper pulley, I was able to achieve around 430rwhp. This was on an essentially otherwise stock car and the power delivery was transformed, even though the way that the 1.7 was adapted was very poor and blocked a lot of airflow. I ran this 1.7 supercharger for many thousands of miles without issue, and as far as I know it remains happily in use in New Zealand with another forum member.
As avos stated in his original post, the 2.1KB is better again than the 1.7 and can comfortably make 450rwhp on our engines. I have mounted the 2.1 KB further forward than avos and was therefore able to optimise the inlet further, achieving virtually unrestricted airflow into the supercharger. I have already put mileage on my kit and tested it under various conditions without any issues, and it has performed even better than the 1.7KB (with which I previously achieved 430rwhp). I estimate with a smaller pulley that 500rwhp will be achievable with the 2.1 KB, and this reportedly already has been achieved on a STR using a ported TB, larger aftermarket MAF and tune.
I am able to re-make these kits for the STR/XJR, which I understand would also fit the SV8 (although I do think the kit would make much more power here and on the X358 XJR). I am currently now working on the X308 XJR and X100 XKR kits, which should be completed this month. If anyone is interested in a kit, please feel free to PM me. The way I have designed the kit means that it is entirely bolt on and reversible, so it can be installed by any DIY mechanic at home.
N.B. If desired, I could in theory make the kit with a 2.6H (or even 2.8 or 3.0 KB) and relocated TB like avos innovatively designed, however in my opinion the 2.1 KB is the best compromise for cost and ease of installation. It also sounds incredible and is louder than the larger units!
Last edited by JagSTR2004; Jul 10, 2024 at 03:11 PM.
Highly interested
Whilst I am not the supercharging expert avos is, I am able to re-make the 2.1 KB kit which avos used to offer and have ran various iterations of twin screw superchargers for around 8 years.
I was able to take a careful look at a 2.1 KB kit supplied by avos and take all relevant measurements in order to reproduce a slightly improved version, with a better finish than the hand-made versions avos made many years ago.
For background, I initially bought a 1.7 Opcon Autorotor from avos around 8 years ago, which I understand made around 380rwhp on his 4.0 XKR (up from a stock 320rwhp). On my 4.2 STR, it made just over 400rwhp with a 2.5" upper pulley. After switching to a 2.16" upper pulley, I was able to achieve around 430rwhp. This was on an essentially otherwise stock car and the power delivery was transformed, even though the way that the 1.7 was adapted was very poor and blocked a lot of airflow. I ran this 1.7 supercharger for many thousands of miles without issue, and as far as I know it remains happily in use in New Zealand with another forum member.
As avos stated in his original post, the 2.1KB is better again than the 1.7 and can comfortably make 450rwhp on our engines. I have mounted the 2.1 KB further forward than avos and was therefore able to optimise the inlet further, achieving virtually unrestricted airflow into the supercharger. I have already put mileage on my kit and tested it under various conditions without any issues, and it has performed even better than the 1.7KB (with which I previously achieved 430rwhp). I estimate with a smaller pulley that 500rwhp will be achievable with the 2.1 KB, and this reportedly already has been achieved on a STR using a ported TB, larger aftermarket MAF and tune.
I am able to re-make these kits for the STR/XJR, which I understand would also fit the SV8 (although I do think the kit would make much more power here and on the X358 XJR). I am currently now working on the X308 XJR and X100 XKR kits, which should be completed this month. If anyone is interested in a kit, please feel free to PM me. The way I have designed the kit means that it is entirely bolt on and reversible, so it can be installed by any DIY mechanic at home.
N.B. If desired, I could in theory make the kit with a 2.6H (or even 2.8 or 3.0 KB) and relocated TB like avos innovatively designed, however in my opinion the 2.1 KB is the best compromise for cost and ease of installation. It also sounds incredible and is louder than the larger units!
I was able to take a careful look at a 2.1 KB kit supplied by avos and take all relevant measurements in order to reproduce a slightly improved version, with a better finish than the hand-made versions avos made many years ago.
For background, I initially bought a 1.7 Opcon Autorotor from avos around 8 years ago, which I understand made around 380rwhp on his 4.0 XKR (up from a stock 320rwhp). On my 4.2 STR, it made just over 400rwhp with a 2.5" upper pulley. After switching to a 2.16" upper pulley, I was able to achieve around 430rwhp. This was on an essentially otherwise stock car and the power delivery was transformed, even though the way that the 1.7 was adapted was very poor and blocked a lot of airflow. I ran this 1.7 supercharger for many thousands of miles without issue, and as far as I know it remains happily in use in New Zealand with another forum member.
As avos stated in his original post, the 2.1KB is better again than the 1.7 and can comfortably make 450rwhp on our engines. I have mounted the 2.1 KB further forward than avos and was therefore able to optimise the inlet further, achieving virtually unrestricted airflow into the supercharger. I have already put mileage on my kit and tested it under various conditions without any issues, and it has performed even better than the 1.7KB (with which I previously achieved 430rwhp). I estimate with a smaller pulley that 500rwhp will be achievable with the 2.1 KB, and this reportedly already has been achieved on a STR using a ported TB, larger aftermarket MAF and tune.
I am able to re-make these kits for the STR/XJR, which I understand would also fit the SV8 (although I do think the kit would make much more power here and on the X358 XJR). I am currently now working on the X308 XJR and X100 XKR kits, which should be completed this month. If anyone is interested in a kit, please feel free to PM me. The way I have designed the kit means that it is entirely bolt on and reversible, so it can be installed by any DIY mechanic at home.
N.B. If desired, I could in theory make the kit with a 2.6H (or even 2.8 or 3.0 KB) and relocated TB like avos innovatively designed, however in my opinion the 2.1 KB is the best compromise for cost and ease of installation. It also sounds incredible and is louder than the larger units!
