BlueStreak Builds A Racecar

[xBlueStreakx]

This is the best progress photo I could dig up. The process was as follows:
- Remove windshield wiper motor and mechanism (because they'll be useless)
- Remove heavy cowl piece and dispose of.
- Build a small dam between the top most cowl piece (I think, its been a year since I had the whole cowl area fully assembled) and the underside of the hood. Mine was done with a ~2" high piece of plastic. I'll take a photo of what that dam looks like this weekend.
- Spread vaseline along the underside of the hood between the air dam and the windshield. You can also spread vaseline along the windshield as well to make it removable in the future. You'd need to find a way to secure it afterwards.
- Spray Great Stuff expanding foam into the cavity and let it dry for a few days. Letting it dry for a few days is very important.
- Run a sharp knife along the hood line and parallel to the ground.
- Using a 100 grit sanding sponge, sand the foam surface down so it forms a ~2mm lip below the hood line.
- Coat the foam surface in PVA glue. Let it dry for a few days.
- Mix acetone and ABS plastic pieces (I used small ABS pipe couplings) into a mason jar and let it sit for a few days. You need to get the Acetone/ABS ratio such that it forms a pretty thick slurry.
- Pour said slurry onto foam surface. You may need to build small dams at the ends of the foam to prevent the slurry from running into the engine bay.
- Assuming you made the slurry runny enough, it'll spread along the foam surface and be dammed by the lip at the hood and the ends. In a few days, when its fully dry, you'll have an almost glass smooth air dam that is perfectly contoured.

[bionicbelly]

Thanks! That is great info. Honestly never occurred to me to do this. Probably won't get to it for awhile. I really like where this is going.

[xBlueStreakx]

Tire of choice for 2018. Kumho V720 ACR.

I'm growing out my mullet, boys.

[spxxx]

Originally Posted by xBlueStreakx

Tire of choice for 2018. Kumho V720 ACR.

I'm growing out my mullet, boys.

I've heard these grip > the RE71s. Super cool option but only for 19s. I hear whispers that this compound may be released for other sizes.

[xBlueStreakx]

Yessir. Confirmed with two Gridlife Time Attack competitors that they offer substantially more grip than the RE71R. I think it comes at far worse tread life than the RE71R, though.

I'll definitely be cycling between the ACR setup for competition and my 265/35/18 RE71Rs for setup/qualifying/HPDE days.

[xBlueStreakx]

Most recent arrival. G-LOC pads.

[xBlueStreakx]

And in summary. What has happened so far... but with Canadian Dollars... so imagine bills of different colours.

[xBlueStreakx]

Got to building the splitter. Not done yet but I'm happy with how its turning out.

I have since upgraded to 1.75" wide washers underneath to prevent the bolt heads from pulling through the alumalite.

[bbnks2]

Originally Posted by xBlueStreakx

Got to building the splitter. Not done yet but I'm happy with how its turning out.

I have since upgraded to 1.75" wide washers underneath to prevent the bolt heads from pulling through the alumalite.

Where did you buy the alumalite. I was thinking about using birch wood but it's much heavier than this stuff.

[xBlueStreakx]

Originally Posted by bbnks2

Where did you buy the alumalite. I was thinking about using birch wood but it's much heavier than this stuff.

Bought it from a sign shop.

[xBlueStreakx]

Some suspension talk.

Last year, I started the season with:
- 616F/1008R Springs
- Stock swaybar up front. Disconnected rear swaybar (doubt it does anything with that much spring anyways...)
- -3.5*F/-2.5*R Camber
- Zero toe all around.

Did a personal best of 1:31.28 at Mosport. Overall handling had a bias towards understeer; even with trail braking. The only way to loosen up the rear was either with an aggressive downshift to 2nd gear or aggressive throttle application in 2nd. Unfortunately, given that Mosport is a very high speed track, 2nd gear is never used.

For shits and giggles, I disconnected the front swaybar and went again. Body roll was significantly higher but didn't feel slower. Turns out my butt G meter was wrong as the car went much slower. 1:33.X was the best I could manage.

With the original settings, I noticed extensive wear on the outside shoulders of the front RE71R tires. Thinking that I may have too much body roll (I have photos showing significant compression of the suspension), I installed a H&R front sway bar. Trials at Mosport again revealed that it was slower. No matter how hard I drove, the best I could manage was a high 1:32.x. The amount of understeer was frustrating.

SO... The plan for this year...
- 616F/1232R Springs
- Stock swaybar up front.H&R Rear sway bar
- -3.5*F/-2.5*R Camber
- Zero toe up front. OEM toe in the back.

Hoping this will make the car more neutral. I'm adding in some rear toe in case the rear end wants to get too playful. My dad joins in on HPDEs and I need it to be on the stable side as he is very much a beginner.

As an aside, my classing (its a points based system) only allows me to run one aftermarket swaybar. Running two will bump me up a class which is not an option for 2018.

[berns]

Originally Posted by xBlueStreakx

Some suspension talk.

Last year, I started the season with:
- 616F/1008R Springs
- Stock swaybar up front. Disconnected rear swaybar (doubt it does anything with that much spring anyways...)
- -3.5*F/-2.5*R Camber
- Zero toe all around.

Did a personal best of 1:31.28 at Mosport. Overall handling had a bias towards understeer; even with trail braking. The only way to loosen up the rear was either with an aggressive downshift to 2nd gear or aggressive throttle application in 2nd. Unfortunately, given that Mosport is a very high speed track, 2nd gear is never used.

For shits and giggles, I disconnected the front swaybar and went again. Body roll was significantly higher but didn't feel slower. Turns out my butt G meter was wrong as the car went much slower. 1:33.X was the best I could manage.

With the original settings, I noticed extensive wear on the outside shoulders of the front RE71R tires. Thinking that I may have too much body roll (I have photos showing significant compression of the suspension), I installed a H&R front sway bar. Trials at Mosport again revealed that it was slower. No matter how hard I drove, the best I could manage was a high 1:32.x. The amount of understeer was frustrating.

SO... The plan for this year...
- 616F/1232R Springs
- Stock swaybar up front.H&R Rear sway bar
- -3.5*F/-2.5*R Camber
- Zero toe up front. OEM toe in the back.

Hoping this will make the car more neutral. I'm adding in some rear toe in case the rear end wants to get too playful. My dad joins in on HPDEs and I need it to be on the stable side as he is very much a beginner.

As an aside, my classing (its a points based system) only allows me to run one aftermarket swaybar. Running two will bump me up a class which is not an option for 2018.

Why not run M3 bars then, since they aren't aftermarket? How big is the h&r bar?

[xBlueStreakx]

Sorry. Should've been more specific. Any bars that don't come with the 135 model are considered a modification. Heck, some folks in the time attack organization argue that disconnecting an OE bar is a modification

To that, I don't care to argue/dispute things. My car was classed lower last year and ended up being faster than those 1-2 classes higher than mine. This year, I'm moving up a class and also optimizing what I already have so I suspect it'll play out the same. *knock on wood*

Looks like the H&R front bar is 27mm. Rear is 20mm.

[bionicbelly]

Originally Posted by xBlueStreakx

Some suspension talk.

Last year, I started the season with:
- 616F/1008R Springs
- Stock swaybar up front. Disconnected rear swaybar (doubt it does anything with that much spring anyways...)
- -3.5*F/-2.5*R Camber
- Zero toe all around.

Did a personal best of 1:31.28 at Mosport. Overall handling had a bias towards understeer; even with trail braking. The only way to loosen up the rear was either with an aggressive downshift to 2nd gear or aggressive throttle application in 2nd. Unfortunately, given that Mosport is a very high speed track, 2nd gear is never used.

For shits and giggles, I disconnected the front swaybar and went again. Body roll was significantly higher but didn't feel slower. Turns out my butt G meter was wrong as the car went much slower. 1:33.X was the best I could manage.

With the original settings, I noticed extensive wear on the outside shoulders of the front RE71R tires. Thinking that I may have too much body roll (I have photos showing significant compression of the suspension), I installed a H&R front sway bar. Trials at Mosport again revealed that it was slower. No matter how hard I drove, the best I could manage was a high 1:32.x. The amount of understeer was frustrating.

SO... The plan for this year...
- 616F/1232R Springs
- Stock swaybar up front.H&R Rear sway bar
- -3.5*F/-2.5*R Camber
- Zero toe up front. OEM toe in the back.

Hoping this will make the car more neutral. I'm adding in some rear toe in case the rear end wants to get too playful. My dad joins in on HPDEs and I need it to be on the stable side as he is very much a beginner.

As an aside, my classing (its a points based system) only allows me to run one aftermarket swaybar. Running two will bump me up a class which is not an option for 2018.

This is EXCELLENT info. Thanks for that. I ended up with 650lb springs for the front with the shocks I got. Been kinda worried about it, but AST said it would be a great rate for the car, and I kinda suspected it would be, as the street tire guys are running 450-500. I don't have aero, so there is that, but I feel like 650 should be in the ballpark, though I may have to lighten it up a bit.

[arc_resistant]

Originally Posted by xBlueStreakx

Some suspension talk.

Last year, I started the season with:
- 616F/1008R Springs
- Stock swaybar up front. Disconnected rear swaybar (doubt it does anything with that much spring anyways...)
- -3.5*F/-2.5*R Camber
- Zero toe all around.

Did a personal best of 1:31.28 at Mosport. Overall handling had a bias towards understeer; even with trail braking. The only way to loosen up the rear was either with an aggressive downshift to 2nd gear or aggressive throttle application in 2nd. Unfortunately, given that Mosport is a very high speed track, 2nd gear is never used.

For shits and giggles, I disconnected the front swaybar and went again. Body roll was significantly higher but didn't feel slower. Turns out my butt G meter was wrong as the car went much slower. 1:33.X was the best I could manage.

With the original settings, I noticed extensive wear on the outside shoulders of the front RE71R tires. Thinking that I may have too much body roll (I have photos showing significant compression of the suspension), I installed a H&R front sway bar. Trials at Mosport again revealed that it was slower. No matter how hard I drove, the best I could manage was a high 1:32.x. The amount of understeer was frustrating.

What did the car feel like when you unhooked the front bar?
Another forum member did this, GingerExtract I think, and posted video. Car was very twitchy, obviously loose.

I can imagine that initial turn in response would be slower due to reduced effective front roll rate, but once car takes a set it should 'carve' better with the rear springs taking more load (higher tire slip angles).

Where do you think you were losing time? High speed corners? Low? Inability to put the power down?

Thx for your thoughts.

[xBlueStreakx]

Originally Posted by bionicbelly

This is EXCELLENT info. Thanks for that. I ended up with 650lb springs for the front with the shocks I got. Been kinda worried about it, but AST said it would be a great rate for the car, and I kinda suspected it would be, as the street tire guys are running 450-500. I don't have aero, so there is that, but I feel like 650 should be in the ballpark, though I may have to lighten it up a bit.

Glad my findings could help.

Originally Posted by arc_resistant

What did the car feel like when you unhooked the front bar?
Another forum member did this, GingerExtract I think, and posted video. Car was very twitchy, obviously loose.

I can imagine that initial turn in response would be slower due to reduced effective front roll rate, but once car takes a set it should 'carve' better with the rear springs taking more load (higher tire slip angles).

Where do you think you were losing time? High speed corners? Low? Inability to put the power down?

Thx for your thoughts.

The car definitely felt like it was carving in the high speed corners which initially made me think I was faster. The laptimes said otherwise.

Putting power down was definitely not an issue. I have a LSD and - at the time - stock tune. Not the best feedback in that regard unfortunately. I can give you better feedback this summer with the new setup and an engine tune. Target is 355whp (to stay in class) and at most 400wtq.

[xBlueStreakx]

Originally Posted by xBlueStreakx

Glad my findings could help.



The car definitely felt like it was carving in the high speed corners which initially made me think I was faster. The laptimes said otherwise.

Putting power down was definitely not an issue. I have a LSD and - at the time - stock tune. Not the best feedback in that regard unfortunately. I can give you better feedback this summer with the new setup and an engine tune. Target is 355whp (to stay in class) and at most 400wtq.

Further to the above, attached is the F/R suspension frequency (for 616F/1008R) that prevails given the car's weight (/w me in it) and F/R weight distribution. Unsprung mass is assumed to be 105lbs per corner.

Going to 616F/1232R makes the F/R frequencies almost identical (rear is still a tad softer).

If my F/R weight distribution was 50/50 as per factory, I would need a roughly 1:3 F/R spring ratio to maintain similar F/R frequencies.

w.r.t suspension setup, this is more of a documentary of "my journey". As the car is primarily my responsibility to build/maintain, I don't want to make the car undriveable/dangerous because I don't want to put my father in a bad position on the track. If I were the only driver, I'd definitely be more aggressive with alignments/spring choice/spring changes etc.

[bbnks2]

Originally Posted by xBlueStreakx

Further to the above, attached is the F/R suspension frequency (for 616F/1008R) that prevails given the car's weight (/w me in it) and F/R weight distribution. Unsprung mass is assumed to be 105lbs per corner.

Going to 616F/1232R makes the F/R frequencies almost identical (rear is still a tad softer).

If my F/R weight distribution was 50/50 as per factory, I would need a roughly 1:3 F/R spring ratio to maintain similar F/R frequencies.

w.r.t suspension setup, this is more of a documentary of "my journey". As the car is primarily my responsibility to build/maintain, I don't want to make the car undriveable/dangerous because I don't want to put my father in a bad position on the track. If I were the only driver, I'd definitely be more aggressive with alignments/spring choice/spring changes etc.

Your wheel rates are significantly different and thats not even factoring in the front bar which adds over 300lb/in effective wheel rate in roll. Basically, you have almost 3x the front roll stiffness as rear.

You aren't rolling over onto your tires shoulder because the suspension is too soft. Youre overworking the tires since they are now doing all the damping. The tires can't handle the load.

[xBlueStreakx]

Need to look at wheel frequency. Wheel rates do not factor in weight distribution.

You would be correct that the wheel rates are not complimentary if I had 50/50 weight distribution. That is not the case. I'm also just talking strictly spring rates as well here.

[bionicbelly]

Which brake compounds did you get?

[xBlueStreakx]

Originally Posted by bionicbelly

Which brake compounds did you get?

GLOC R12 front/R8 rear. This combination allows for the brakes to be effective right from the outlap.

R16 front/R12 rear would be ideal but I'm working with the dad factor here. Haha.

[xBlueStreakx]

Attached is the resulting suspension frequency from the spring rates I'll be trying this year (bars not included). The rear is about 5% softer than the front. If I wanted to make the suspension frequencies the same, I would need a 1344lbs spring out back.

So to restate, I'll be trying the above combination with a OEM front bar and H&R rear bar. I expect the rear end to be much more playful than last year.

Will report back on how the car behaves (in April/May) at Mosport. This is the track I have the most seat time and lap data on. It is also the highest risk track that I run on and pretty much the only track my father runs on (HPDEs only for him).

What I'll be looking for is a) how the car behaves overall and b) how the car behaves specifically on turn 4. As a reminder, turn 4 is a very high speed turn /w entry at 190KM/h and throttle held wide open the entire time. The entire turn has a massive elevation drop that makes the rear end step out about 12" despite trying to keep the weight on the rear with the throttle; this helps tuck the front end in nicely. If I were to be picky, it could stand to tuck in some more but I have my own pucker factor to deal with. There is zero run off at that turn and an off track experience there will have the car being written off at a minimum.

Another caveat to all of this is the power bump the car will have. Stock to 355whp is very material which has implications on the attitude of the car on every corner. w.r.t turn 4, there is a very good chance that the newfound speed would overwhelm the chassis regardless so a lift may be required.