Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

Go to Thread: PreviousNext
Go to: Forum ListMessage ListNew TopicLog In
Goto Page: 12Next
Current Page: 1 of 2


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: August 20, 2009 03:29PM

Hello everyone,

I'm in the process of researching turning my TR7 into a TR7V8 and as part of the project I've decided on converting to IRS.

I've read a few articles here and there and then came to this amazing forum and saw IRSs in MG and a really cool Standard.

Can anyone elaborate or point me in the direction of a TR7V8/TR8 build details or "How-to"?

Can anyone share any insight and specifics like which IRS units, cradle measurements and axle shaft lenghts, etc?

Thank you for anything you may share with me.

Trip



Edited 2 time(s). Last edit at 08/20/2009 04:12PM by TRip.


Moderator
Curtis Jacobson
Portland Oregon
(4495 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: Moderator
Date: August 20, 2009 05:17PM

Welcome to the forum! Sounds like you'll fit in perfectly here.

I don't know much about IRS, so I'll leave that for someone else. (Jim?)

I'm kinda curious though... what are you hoping to accomplish with IRS? Do you want IRS because it's a really cool fabrication project and a chance to learn a lot about vehicle dynamics? Or are you mainly interested in ride quality? Or maybe you're building this car for scrambling over boulders? Most of the projects around here aren't all that "practical". Nothing wrong with that! But it might help if we knew more about your vision for what you want to have when you're all done.

Also, you might want to post your question in the suspension/handling forum section to reach a broader cross-section of people.


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: August 20, 2009 05:36PM

Hello Curtis, thank you for welcoming me.

I really do have a feeling that I'll fit right in here!

IRS for all the reasons you mentioned except "scrambling over boulders".

I know it's not practical especially when a moded LSD solid axle will "work". But, I happen to think practical = Boring!

It's a challenge, it's a chance to learn new things, skills, communicate with like minded enthusiasts and it's different from most TR7/8s.

I also would like to install a Rover V8 with 300hp (maybe not so reasonable goal) and have a rear end that'll hold up and add to the performance at the same time.

I'm just now starting out and in the research phase. It'll be some time till knowledge and savings meet, though. LOL

BTW: The suspension dynamics angle (no pun intended) is also fascinating... And, from what I've seen here, the folks on this forum are fantastically knowledgeable and insightful.

Thanks for the suspension/handling forum posting suggestion. I don't know how to transfer over though(?)

Thanks for the welcome, Curtis.

Trip


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6070 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: BlownMGB-V8
Date: August 20, 2009 08:16PM

Trip, welcome. I don't know what's been done with the TR, but maybe Dan B. has seen something. He's a dyed in the wool TR guy and lots of TR's were IRS so he might have seen something that would help you get started. He's also anticipating an engine swap when his TR7 needs it, so we've been looking at engine choices. I just bought Edith a TR7 with a Buick V6. Lots of potential there but I'd look real close at the 2010 Camaro driveline. 3.6L V6 with direct injection and active cam timing control on intake and exhaust independently (dohc) on a 60* engine with about 305hp and over 30mpg. Lots to like about that one.

The Jag is probably overkill a little bit. But we have a couple of threads on IRS conversions. Spend a little time wandering through the old posts. There's lots of good comparison info there.

Jim


Dan B
Dan Blackwood
South Charleston, WV
(976 posts)

Registered:
11/06/2007 01:55PM

Main British Car:
1966 TR4A, 1980 TR7 Multiport EFI MegaSquirt on the TR4A. Lexus V8 pl

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: Dan B
Date: August 21, 2009 09:11AM

An X type might be worth looking at.


WedgeWorks1
Mike Perkins
Ellicott City, Maryland
(460 posts)

Registered:
07/06/2008 08:07AM

Main British Car:
1980 Triumph TR8 3.5 Litre Rover V8

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: WedgeWorks1
Date: August 21, 2009 09:27PM

Trip-
The TR7 body is really not set up for IRS. The frame rails would need a lot of work moving them inward and possibly removal to for an IRS unit. You would also have to get the IRS load back to the floors since originally designed the four link suspension put all the stress into the floors and rear bulk head. with just springs and shocks connecting to the rear rails. In my opinion it is way too much work and expense. It is so much easier to get a Ford or a Dana LSD rear axle and have it shortend and the original mounting brakets welded on and be a bolt in. If you plan on 300+ horse those rear ends will easily handle that power and more with a huge range of gears to choose from. Be sure to reinforce the control arm mounting areas on the outside and inside of the car. They cannot handle a lot of torque and will eventually tear apart. Good luck!


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independent rear suspension (IRS) for TR7V8
Posted by: TRip
Date: August 22, 2009 02:06AM

Thank you Jim.... Isn't a Buick V6 basically a 3500 minus 2 cylinders? I hear it's super strong too!

The 2010 Camaro driveline is really nice. Wouldn't it cost far more than piecing together good rebuilt Rover bits, though(??)

Plus, there really is something to be said for that V8 rumble.

Dan, I'll check out what I can on X types. Thanks

Mike, You've made very strong points regarding "frame rails" and getting "the IRS load back to the floors since originally designed the four link suspension".

I wonder if a carrier can be fabricated to tie everything together and address the frame rail and load issues?

I'm very glad to have insights from all of you.

Trip



Edited 1 time(s). Last edit at 08/22/2009 02:18AM by TRip.



WedgeWorks1
Mike Perkins
Ellicott City, Maryland
(460 posts)

Registered:
07/06/2008 08:07AM

Main British Car:
1980 Triumph TR8 3.5 Litre Rover V8

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: WedgeWorks1
Date: August 22, 2009 07:27AM

Trip-
You would need to consider the dimensions of the IRS assembly, wheel travel & angles and from there how much rear frame rail and inner wheel arch modifications will be required. You could bring braces to the floors to get the stresses back up front. It still seems like a ton of work.......


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6070 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: BlownMGB-V8
Date: August 22, 2009 11:50AM

Trip, check out what we did on the MGB-Roadmaster thread and the 340 upgrade thread in the MG forum. Also look at Calvin's work on upgrading his TR6 to a hybrid Nissan/TR IRS. We modified a Jag IRS to bolt into the regular MGB solid axle mount points with no modifications to the body. I would assume a similar approach should work for the TR7, although Mike is right, any stiffening you would need for a solid axle would also probably be needed for the IRS for a given power level.

Jim


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: August 22, 2009 01:54PM

Thank you Mike and Jim.

It's really very nice to have honest and straight insights. It's grounding and keeps me from unrealistic goals.

Although this IRS idea is now becoming a little daunting. I'm still enthusiastic about it as a learning project. Jim, I'll search for the projects you mentioned.

Thanks again for your knowledge.

Trip


turbospitfire
Max Brewster

(49 posts)

Registered:
04/25/2008 01:05PM

Main British Car:
1979 Triumph Spitfire Ford 2.3 Liter Turbo

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: turbospitfire
Date: September 02, 2009 04:21PM

You might consider an early '89 - '97 Mercury Cougar & Ford T-Bird IRS. The Monster Miata conversion kits use this setup. One advantage is that they are cheap at a junk yard and offer a variety of gear ratios. You may have to deal with narrowing the axles. I found that if you can find a CV joint re-builder they may find shorter axles with same spline. This avoids welding axles. See below for an example of what it looks like in a fabricated frame.

[www.factoryfive.com]

Cheers,
Max Brewster
1979 Triumph Spitfire
2.3 Ford Turbo


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: September 02, 2009 10:47PM

Thank you for the lead, Max,

I'll check out your link.

BTW, wouldn't the control arms have to be shortened too and new geometry calculated for the TR7?

Cheers,

Trip



Edited 1 time(s). Last edit at 09/02/2009 10:51PM by TRip.


Dan B
Dan Blackwood
South Charleston, WV
(976 posts)

Registered:
11/06/2007 01:55PM

Main British Car:
1966 TR4A, 1980 TR7 Multiport EFI MegaSquirt on the TR4A. Lexus V8 pl

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: Dan B
Date: September 03, 2009 10:19AM

Hey Trip,

I just ran across this on the TriumphTr7.com forum: [www.triumphroverspares.com.au]

Obviously it is being done in Australia.

Dan


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: September 03, 2009 02:32PM

Hello Dan,

I emailed them. Phil at TRS replied by saying that they are no longer available.

I think their price was really high when they were selling it. I recall around $5500.

Thank you for the lead.

Trip


turbospitfire
Max Brewster

(49 posts)

Registered:
04/25/2008 01:05PM

Main British Car:
1979 Triumph Spitfire Ford 2.3 Liter Turbo

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: turbospitfire
Date: September 04, 2009 02:42PM

Hi Trip, yes all the suspension needs reworking. I went through this with my conversion since I removed the transverse leaf and built an unequal a-arm coil over suspension. It was challenging. One more option would be the rear suspension subframe, including control arms, hubs etc, from a second generation RX7. It may be close in width to the TR7. However, I would not use the RX7 differential because you are limited in available gear ratios. Monster Miata sells a kit to use the T-bird differential and they provide axles and wheel flanges. It may cost more but it is another possibility.

Cheers,
Max



turbospitfire
Max Brewster

(49 posts)

Registered:
04/25/2008 01:05PM

Main British Car:
1979 Triumph Spitfire Ford 2.3 Liter Turbo

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: turbospitfire
Date: September 04, 2009 02:50PM

Trip, I should clarify. You may have to call Monster Miata to see if they would sell the parts separately for the differential swap.

Max


TRip
Trip Anthony

(162 posts)

Registered:
08/18/2009 01:16AM

Main British Car:
1980 TR7 performance 4 cyl

Re: Independant rear suspension (IRS) for TR7V8
Posted by: TRip
Date: September 04, 2009 02:54PM

Hi Max.

RE: your conversion - "It was challenging". I can see how it would have been a challenge. The cool part is that you overcame the issues.

RX7... that's an interesting option.

I'll take a look at the Miata kit and also look into some sort of swap possibility.

Thanks Max,

Trip



Edited 1 time(s). Last edit at 09/04/2009 03:01PM by TRip.


DudleyTR8
Justin Evert

(1 posts)

Registered:
05/10/2021 07:47PM

Main British Car:


Re: Independant rear suspension (IRS) for TR7V8
Posted by: DudleyTR8
Date: May 10, 2021 07:53PM

Has there been anymore progress from this idea? Has anyone else tried this as well?


tr8todd
Todd Kishbach

(381 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Independant rear suspension (IRS) for TR7V8
Posted by: tr8todd
Date: June 12, 2021 08:21AM

I grabbed an independent 8.8 out of a Thunderbird, and also grabbed an aluminum case from a Lincoln. Some day I will shorten the axles and build a carrier to put it in my LS3 powered TR8. For now the stick 8.8 from an Explorer will have to do. The Thunderbird 8.8 is the way to go. It has carriers that point the control arms 90* straight back at the center section. Makes fabrication easy. Thats why its the rear end of choice for the Miata V8 conversions, and for Cobra kit cars. There is so much demand for these units, that Ford Motorsports has begun making and selling just the carriers again. You can snag an independent center section from an 98 onward Explorer, or later Lincolns, and then fabricate the control arms, axles, and carrier. I messed around with the independent that came in my donor 2010 Camaro SS. Proved unusable. Minimum wheel size would have been 18" to clear the carrier, and the control arms pointed at weird angles. Supposedly those angles and control arm lengths were decided on by a computer modeling program to minimize castor camber changes during wheel travel. Not at all duplicatable in a small Brit sports car. Shame really, because it was a very nice unit. Center section was aluminum and had a limited slip from the factory. Sold it for more than I paid for the Thunderbid unit and its rebuild parts, so I guess I made out.


Dan B
Dan Blackwood
South Charleston, WV
(976 posts)

Registered:
11/06/2007 01:55PM

Main British Car:
1966 TR4A, 1980 TR7 Multiport EFI MegaSquirt on the TR4A. Lexus V8 pl

authors avatar
Re: Independant rear suspension (IRS) for TR7V8
Posted by: Dan B
Date: June 17, 2021 06:16PM

I saw some information on another board a few years ago about using a Merkur or Scorpion IRS. It sounded promising, except they are rare.
Goto Page: 12Next
Current Page: 1 of 2


Sorry, only registered users may post in this forum.