[RallyBob]

Charles, I have a set of 16 x 7.5" TSW's with 205/45-16 tires that fit a Manta with no issues. I lost a tire two years ago to a pothole, so I will probably upgrade them to 215/40-16's to keep the diameter reasonable but get a bit more tire contact patch on the road.

 

[RallyBob]

Do they fit a Manta with lowered suspension, or do they only fit the stock ride height? I have a set of 16"x7" rims that I wanted to use on a Manta but held off because the car has been lowered ~2".

I had them on my Ascona with 2.875" drop in front, and 2.5" drop out back. Only fitted them to a stock height Manta however. Tire diameter and wheel offset is the key to eliminating tire rub.

As well, front sway bar bushings should be new....a-arms that move fore and aft create tire rub on the lower valance!

 

[RallyBob]

Manta 75' Front brakes

Charles, go bigger on the front brakes, they do 75% of the stopping. I recently drove Duane's Ascona (1965 lbs, about 160 hp), and the 1975 front brakes were GONE (as in massive brake fade and pedal to the floor) after just 4 passes in a parking lot. See my video here.

With 185 hp, lots of torque, and a full-weight Manta, you will need vented front disc brakes and better calipers. Or airbags....:no:

 

[RallyBob]

I was disappointed by the 75s I put on my GT. But I had heard that they were only marginally better than stock.

Well, in truth the pad material makes more of a difference than anything else. I have used the Porterfield R4-S on 1975 brakes and they resisted fade better than the BMW vented front rotors I used to run with Metal Master pads. But you get what you pay for!

Metal Masters - about $28 back in the mid 1990's
Porterfield R4-S - about $120 these days

I recently got some Hawk HPS pads to try out on 1975 brakes, we'll see if they're comparable to the Porterfields. They only cost $70 and are available from Summit Racing.

 

[RallyBob]

The compression height 05 LK5 vin 8 is........1.101
as per http://www.kb-silvolite.com/assets/09_silvolite_catalog.pdf

So with a 5.557" rod you're all set...:banghead:

 

[RallyBob]

Anyway, I have sent another one to Keith and see what he can do.. because I would love for a solution that doesn't include a 7" high hood scoop at the rear.

It doesn't look like it would be all that hard to just make a new intake manifold from scratch from aluminum. It certainly wouldn't have to be that tall!

 

[RallyBob]

The key is the funky shapes of the intakes, they also use a rubber gasket built into the plastic flange.

You could either machine an o-ring groove into a new aluminum flange or delete the o-ring altogether and make a gasket from more conventional material.

What do you think if you cut the runners about a inch from where they collect, got a oval shape of aluminum and cutout the shape of the runner into and epoxied it together? Would that hold up? I think the throttle body could fit to the end of the tube like on the Opel.

I wouldn't trust the plastic/aluminum bond unless there was also an interference (press) fit. Many modern plastics simply can't be glued together.

The reason its so tall is that is is a C shape and goes over the engine. If not for that, the engine would be really close to matching the height of the CIH as well. Still a bit taller but no worse that the total height including the Manta Air Cleaner.

You'd want to keep the runners as long as stock since that is an appreciable part of the design intent...longer runners aid in torque. But no one said you couldn't extend the runners straight out towards the fender. Even downhill (invert the 'c').

 

[RallyBob]

Any chance we could send you an Atlas Manifold to make up something Could drop it off/show you it at Carlisle.

Also if I have to lose a little power to make the hood fit I wouldnt be terribly upset. Since at 175HP and 185FT/LBs even if it was a 10% loss, I would still have a killer motor

I see no reason why you'd have to lose any power if it was built right.

However I'm not the guy to do that, and I'm not going to Carlisle any time soon. In fact with my current projects going on, I'd be surprised if I work on anything that's Opel-related before summer.:yup:

 

[RallyBob]

. . . the standard 1.9 rod length, Bob, or one of your alternate, modified 'standard' rods from another make? . . . Chevy, Ford, Volvo?

Total sarcasm. I don't know of any rods that length that will work. Opel used 128 mm rods (1.5 through 2.2 CIH engines) and 134 mm rods (2.4 CIH engines).

The 2.2 Opel compression height is 1.619", which is quite a bit different than 1.101"!

 

[RallyBob]

A lot of it comes down to what Kieth said, we aren't GM engineers.

Once the car is running and everything works, then trying to modify the intake may be in the plans.

But rather just modify the hood, get the car running, and then start playing with other options. Hate to never get the car running and not know if it was because of modifications to the intake.

Seems you could have gotten the car fired 'as is', before modding the hood. If it runs right, then make a new intake manifold that would clear the stock hood, matching the runner lengths and the plenum volume of the OEM manifold. Put the sensors in the same general locations as stock. Why wouldn't it work?

Just a thought.

 

[RallyBob]

In the smaller Manta engine bay its worse.

I see a ton of room for an intake. At least compared to a GT...:yup:

 

[RallyBob]

How much could you drop the engine if you did a combo of mods? Notch and reinforce the front crossmember, and mod the oil pan too. Might get you a couple of inches of drop perhaps?

 

[RallyBob]

Front will suspension will have power steering, the Legere gussets, and new bushings. So it should be good.

What about springs and sway bars?

If they're stock, it's really not enough. Maybe not treacherous handling, but not enough to extract the engine's full capabilities. More of a "point and shoot" proposition.

Bob

 

[RallyBob]

I'd go with the 375 lb front springs. Rears are okay @ 170 lbs with a bigger sway bar.

It sounds high but in truth it's only about a 150 lb wheel rate due to the front suspension's motion ratio.

 

[RallyBob]

The motor bay is cleaned up and tightened up.

That thing better move on out, because that is one bigass ugly engine in there!:haha:

 

[RallyBob]

got my eyes on these:

http://www.tirerack.com/tires/tires...ntus+R-S3+(Version+2)&partnum=245WR5Z222V2&vehicleSearch=false&fromCompare1=yes

225/45r15

Hopefully they will fit the body and the Rims

225/45-15 fits 9" rims perfectly. Fits 8" rims okay.

Not worth putting them on 7" rims, might as well run 195's because you lose so much tread "sucking" the sidewalls in on the narrow rims.

This is a 225/45-15 on a 9" rim.

 

[RallyBob]

So they will fit nicely in the body without having to modify it..? Ill check the Rim size.

I never said that.

15 x 8" wheels with 5"-5.25" backspace fit a manta pretty well if you're not excessively lowered and the tire diameter is reasonable. 205/50's fit well. You may need to clearance the front valance and roll the wheel arches. If you go to 9" wheels in back you need 6" back spacing.

 

[RallyBob]

This is a 13 x 9 with 245/50 on a stock wagon. Same wheel wells as a Manta.

6" back spacing. Note the clearance to the inner frame, and how close it is on the outside without a rolled lip. You can go to 6.25" backspace but at that point the wheels will rub the e-brake cable.

 

[RallyBob]

Looks like some of us learned a new term. I'll stick with the one I'm familiar with, strut brace.

Harold

When they rallied the then-new 64-1/2 Mustangs in the Monte Carlo Rally, they had these braces added for chassis rigidity. Hence the name.