MGB & GT Forum
Front end mods... your thoughts on new behavior?
Posted by Thurlowb
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 13, 2017 07:34 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
I have just completed the following changes to the front suspension.
1) I went from the 480lb springs to the 550lb springs. This has the effect of lowering the car just a tiny, tiny bit more.
2) replaced my perfectly fine front dampers with a set of Caldwell adjustables. (Sweet!)
3) replaced the lower control arms with negative camber versions.
Went for a test drive...
The car is now extremely twitchy. If you aren’t hanging onto the wheel tightly, the car will jump left or right as it hits small road bumps.
The steering doesn’t tend to return to center anymore. Once you start a turn, the car really likes It! It feels like you have to pull the car out of the turn or it will just keep turning. It is an unusual feeling.
So...some of the characteristics are what I want for autocrossing, but maybe these effects can be mitigated just a bit.
I have some ideas, but want to hear some opinions first.
1) I went from the 480lb springs to the 550lb springs. This has the effect of lowering the car just a tiny, tiny bit more.
2) replaced my perfectly fine front dampers with a set of Caldwell adjustables. (Sweet!)
3) replaced the lower control arms with negative camber versions.
Went for a test drive...
The car is now extremely twitchy. If you aren’t hanging onto the wheel tightly, the car will jump left or right as it hits small road bumps.
The steering doesn’t tend to return to center anymore. Once you start a turn, the car really likes It! It feels like you have to pull the car out of the turn or it will just keep turning. It is an unusual feeling.
So...some of the characteristics are what I want for autocrossing, but maybe these effects can be mitigated just a bit.
I have some ideas, but want to hear some opinions first.
Dec 13, 2017 07:46 PM
Top Contributor
Joined 17 years ago
11,646 Posts
|
Brad, you need to get the toe reset after adding the negative camber wishbones. The wishbones are primarily responsible for the great turn-in and the twitchiness.
When you next auto-x the car you'll notice a tendency for the front brakes to lock up easier, because now you're riding on the inside edge of the tires. Also, after a bit you'll notice that you're wearing the inside edges of your tires.
When you next auto-x the car you'll notice a tendency for the front brakes to lock up easier, because now you're riding on the inside edge of the tires. Also, after a bit you'll notice that you're wearing the inside edges of your tires.
|
Dec 13, 2017 07:46 PM
Top Contributor
Joined 15 years ago
3,691 Posts
|
I didn't see resetting the toe on your list. Might want to give it a look
Jim
"If you want me to agree with you then we would both be wrong"
'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672
Jim
"If you want me to agree with you then we would both be wrong"
'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 13, 2017 08:04 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
|
Dec 13, 2017 08:19 PM
Top Contributor
Joined 15 years ago
3,691 Posts
|
My guess is that lengthening the lower control arms would cause additional toe in and create the condition you describe. It's a simple thing to check and adjust, buy or build yourself a set of toe plates.
https://i.ytimg.com/vi/TTkSwuXKWpM/maxresdefault.jpg
https://images-na.ssl-images-amazon.com/images/I/317BP9-RA2L.jpg
Jim
"If you want me to agree with you then we would both be wrong"
'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672
https://i.ytimg.com/vi/TTkSwuXKWpM/maxresdefault.jpg
https://images-na.ssl-images-amazon.com/images/I/317BP9-RA2L.jpg
Jim
"If you want me to agree with you then we would both be wrong"
'66 MGB widened 11" with supercharged LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108
Continued in Part 4 http://forum.britishv8.org/read.php?13,40751
Continued in Part 5 http://forum.britishv8.org/read.php?13,48698,48698#msg-48698
Continued in Part 6 http://forum.britishv8.org/read.php?13,61672
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 13, 2017 08:45 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
oleanderjoe
Joseph Baba
|
Dec 13, 2017 08:45 PM
Top Contributor
Joined 10 years ago
27,380 Posts
|
You should also check your Camber; If I remember, 1975 -80 RB Cars had about 1 Degree Positive Camber ?????, Negative camber arms should have given you about 2 Degrees Neg Camber. (Perfect)
If you need I can post up a drawing on how to do it pretty easily. Let us know.
IN ALL SUBJECTS.: For those who believe, no proof is needed. For those who don’t believe, no proof is possible.
"Strive for perfection in everything. Take the best that exists and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough"
Sir Henry Royce
co-founder of Rolls-Royce .
"I take no credit for my own, of another man's fame".
Joe Baba 2021
If you need I can post up a drawing on how to do it pretty easily. Let us know.
IN ALL SUBJECTS.: For those who believe, no proof is needed. For those who don’t believe, no proof is possible.
"Strive for perfection in everything. Take the best that exists and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough"
Sir Henry Royce
co-founder of Rolls-Royce .
"I take no credit for my own, of another man's fame".
Joe Baba 2021
Member Services:
67motorcat
Steve O
|
Dec 13, 2017 09:46 PM
Joined 8 years ago
417 Posts
|
Easy to adjust Toe yourself. Just park your cars front wheels on 3 sheets of wax paper under each front wheel.
Grab a tape measure and reference the tread in the same place in front and behind the tires while adjusting tie rods to a few hairs toe in....done
Grab a tape measure and reference the tread in the same place in front and behind the tires while adjusting tie rods to a few hairs toe in....done
mgblestyle
Philip Shave
|
Dec 14, 2017 08:50 AM
Top Contributor
Joined 7 years ago
616 Posts
|
Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil
Dec 14, 2017 02:24 PM
Joined 7 years ago
29 Posts
|
Brad, First time posted but I live in Coquitlam and in the midst of redoing the suspension on my B. Finished the body and drive train last year
. Would love to connect and compare and see what you haven done. Email me at michaelswan61@gmail.com if your interested
. Would love to connect and compare and see what you haven done. Email me at michaelswan61@gmail.com if your interested
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 14, 2017 05:46 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
In reply to # 3645306 by mgblestyle
Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil
Hopefully, some adjustment to toe-in will tame the car a bit. As is, it might be fine on the autocross course, but I still have to drive it around between races!
As for camber, I'll try to get an accurate measurement of how much negative camber I have actually created. However...if I don't like the answer, what could be done about it? The effect of the lower springs and the (-) camber arms adds up to what it is...there isn't any adjustment in the system. I suppose I could put the taller, softer springs back in...
As it was, I was tearing up the outsides of the front tires...and the tires I ran this past season were not even as soft as my next set will be. So the increased negative camber could only be good for tire wear.
Dec 14, 2017 08:54 PM
Top Contributor
Joined 18 years ago
14,028 Posts
|
In reply to # 3645631 by Thurlowb
Hopefully, some adjustment to toe-in will tame the car a bit. As is, it might be fine on the autocross course, but I still have to drive it around between races!
As for camber, I'll try to get an accurate measurement of how much negative camber I have actually created. However...if I don't like the answer, what could be done about it? The effect of the lower springs and the (-) camber arms adds up to what it is...there isn't any adjustment in the system. I suppose I could put the taller, softer springs back in...
As it was, I was tearing up the outsides of the front tires...and the tires I ran this past season were not even as soft as my next set will be. So the increased negative camber could only be good for tire wear.
In reply to # 3645306 by mgblestyle
Brad, as others have said, checking the toe is necessary. Also measure the camber--the combination of lowering and negative camber control arms may have resulted in excessive negative camber. I used the 480 lb springs to lower my 1980 and the result was -1/4 to -1/2 degree camber, L/R. In other words, the lowering alone will result in negative camber if you do it with springs. Your description of how the car handles sounds a lot like too much negative camber. Phil
Hopefully, some adjustment to toe-in will tame the car a bit. As is, it might be fine on the autocross course, but I still have to drive it around between races!
As for camber, I'll try to get an accurate measurement of how much negative camber I have actually created. However...if I don't like the answer, what could be done about it? The effect of the lower springs and the (-) camber arms adds up to what it is...there isn't any adjustment in the system. I suppose I could put the taller, softer springs back in...
As it was, I was tearing up the outsides of the front tires...and the tires I ran this past season were not even as soft as my next set will be. So the increased negative camber could only be good for tire wear.
Reinstall the stock lower control arms?
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 14, 2017 09:57 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
Dec 14, 2017 10:55 PM
Top Contributor
Joined 19 years ago
6,139 Posts
|
In reply to # 3645725 by Thurlowb
Ha..ha... yes...but that would be giving up on the attempt to make things better. And...I have already proven the prior configuration eats the outside of the tires.
Brad
In reply to # 3645712 by JoeReed
Reinstall the stock lower control arms?
Reinstall the stock lower control arms?
Ha..ha... yes...but that would be giving up on the attempt to make things better. And...I have already proven the prior configuration eats the outside of the tires.
Brad
Brad, a properly aligned stock system (sounds like that is what you had?) should wear the tires evenly. It sounds like you were toed out before and were trying to fix it by introducing negative camber...
Thurlowb
Brad Thurlow
|
Topic Creator (OP)
Dec 14, 2017 11:18 PM
Top Contributor
Joined 13 years ago
2,527 Posts
|
In reply to # 3645733 by lbcnut
Brad, a properly aligned stock system (sounds like that is what you had?) should wear the tires evenly. It sounds like you were toed out before and were trying to fix it by introducing negative camber...
Brad, a properly aligned stock system (sounds like that is what you had?) should wear the tires evenly. It sounds like you were toed out before and were trying to fix it by introducing negative camber...
I think the rapid destruction of the outside edges of my tires had more to do with autocrossing than it did with alignment.
However, if I can’t get the car to behave decently between races I am willing to go back to the old lower arms. I sure hope that some toe adjustment will fix the problems. Certainly the old combo was perfect for road use. I’m just trying to get more out of the car on the race course while keeping it pleasant enough on the street....it is a fine line and it is just possible that this current configuration is a bit too far toward track use.
Brad
Forums
Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster