IMSA Race Road America 2019

**joeb** · 31 Jul 2019, 18:51 (Ref:3920578)

It is race week at my favorite track in North America. Mazda is coming off back to back victories but has been slightly pegged back by the latest BOP. The Juncos Caddy is going to miss this round after the big crash a few weeks ago, but we have Starworks returning with their Audi in GTD.

Schedule

Entry

canaglia · 31 Jul 2019, 21:34 (Ref:3920599)

lol cadillac min. weight pushed to 980kg!!!

can't remeber a cadillac so heavy even when they got the 6.2L

**joeb** · 1 Aug 2019, 02:03 (Ref:3920609)

Quote:

Originally Posted by canaglia

lol cadillac min. weight pushed to 980kg!!!

can't remeber a cadillac so heavy even when they got the 6.2L

I saw that too. That is a ton of weight. How fast could they be at 900 kg? Well they did get a power increase to go along with the weight, so maybe they will be more competitive?

broadrun96 · 1 Aug 2019, 03:20 (Ref:3920615)

Quote:

Originally Posted by joeb

I saw that too. That is a ton of weight. How fast could they be at 900 kg? Well they did get a power increase to go along with the weight, so maybe they will be more competitive?

Were they catching up on long runs and IMSA is trying to manage tire wear? Same speed likely but not so light on their tires so the times are more consistent throughout the stint?

canaglia · 1 Aug 2019, 17:52 (Ref:3920697)

Quote:

Originally Posted by joeb

I saw that too. That is a ton of weight. How fast could they be at 900 kg? Well they did get a power increase to go along with the weight, so maybe they will be more competitive?

it's an insane weight ballast!
2 years ago, none else could get the same torque release because of huge 6.2L and it was fair to be the heaviest car in grid (according to some rumors cadillac dpi real weight was even over bop 950kg) but now GM 5.5L torque curve shouldn't be that different to the acura one!

About 40kg is really too much.

Restrictors don't tune up or down low-mid torque.

carbsmith · 1 Aug 2019, 20:13 (Ref:3920724)

Base weight is 930kg not 900kg. Their weight difference to the Mazda has stayed the same, the problem is everyone has to get fatter because they can't get that pig Nissan below 935kg or run more boost on a GT3 engine without blowing motors. I believe some of us pointed out this problem when they insisted on making LMP2 a separate class and anyone thought DPi was actually going to get faster.

TF110 · 2 Aug 2019, 01:23 (Ref:3920749)

Quote:

Originally Posted by carbsmith

Base weight is 930kg not 900kg. Their weight difference to the Mazda has stayed the same, the problem is everyone has to get fatter because they can't get that pig Nissan below 935kg or run more boost on a GT3 engine without blowing motors. I believe some of us pointed out this problem when they insisted on making LMP2 a separate class and anyone thought DPi was actually going to get faster.

I don't understand why they have to run the GTR engine in the 'nissan'. Why not just use the engine ByKolles was running? Is that somehow against the rules? Is the Chevy engine not a race engine? It must be production based according to their rules or something.

**joeb** · 2 Aug 2019, 02:06 (Ref:3920752)

Quote:

Originally Posted by TF110

I don't understand why they have to run the GTR engine in the 'nissan'. Why not just use the engine ByKolles was running? Is that somehow against the rules? Is the Chevy engine not a race engine? It must be production based according to their rules or something.

I think the Nissan GT3 engine was selected because it was cheap and available. There isn't a production based rule in the DPi regs afaik. A switch to the Cosworth Nissan LMP1 engine would incur a significant cost that Nissan isn't fronting, so that would be up to the single car team running it. Same with Mazda, people were calling for them to use the AER LMP1 engine, but now this old 2 liter unit is making power reliably and winning races. The Nissan has won endurance races with the current engine, not sure why they would switch it.

canaglia · 2 Aug 2019, 08:14 (Ref:3920785)

Quote:

Originally Posted by carbsmith

Base weight is 930kg not 900kg. Their weight difference to the Mazda has stayed the same, the problem is everyone has to get fatter because they can't get that pig Nissan below 935kg or run more boost on a GT3 engine without blowing motors. I believe some of us pointed out this problem when they insisted on making LMP2 a separate class and anyone thought DPi was actually going to get faster.

Actually 930kg is base weight for ACO lmp2, mazda dpi used to run with a min. weight of 915kg. There isn't a min weight for dpi, as it seems for cadillac there isn't a possible max weight as well....

Actually don't think nissan dpi influences that much bop...

also because since they'll surely sticking to more reliable and heavier 2017 engines, likely car is about 950kg heavy.

canaglia · 2 Aug 2019, 08:16 (Ref:3920786)

Quote:

Originally Posted by joeb

I think the Nissan GT3 engine was selected because it was cheap and available. There isn't a production based rule in the DPi regs afaik. A switch to the Cosworth Nissan LMP1 engine would incur a significant cost that Nissan isn't fronting, so that would be up to the single car team running it. Same with Mazda, people were calling for them to use the AER LMP1 engine, but now this old 2 liter unit is making power reliably and winning races. The Nissan has won endurance races with the current engine, not sure why they would switch it.

Nissan involvment in dpi is really poor: gt3 engine + nismo stickers.

broadrun96 · 2 Aug 2019, 11:37 (Ref:3920816)

Quote:

Originally Posted by canaglia

Nissan involvment in dpi is really poor: gt3 engine + nismo stickers.

Hence why he was saying why switch engines? The GTR GT3 lump was relatively easy to procure and fairly inexpensive for ESM, now Core, to source. Spares became a problem at the end and I believe ESM had to withdraw 1 car from a couple races as they only had the 2 engines on hand.

The BOP is most likely driven by the Nissan as the point is to keep all the cars together. It can't really be sped up more and Braun is not slouch in a prototype so they have to restrict the remaining cars a bit. Everything else probably has plenty of pace in hand but in order to keep a long term partner around IMSA is slowing everyone to the Nissan's pace. I understand their thinking and Core is a big part of IMSA and has had a car of some kind in the field for a while.

canaglia · 2 Aug 2019, 12:04 (Ref:3920820)

don't know... to me seems like IMSA increased acura and cadillac min.weight as mazda received a weight ballast too.... basically to penalize everyone.
About gt-r gt3 engine, last year at WG, nismo introduced 2018 specs engines, made with lighter parts but extremely unreliable... infact both ESM had several engines failures during WG week-end and could field just one car at mosport waiting for fresh 2017 engines.

Being DPi basically a bop class, bespoke engines are allowed, but guess coswroth-nismo V6 3L is too expensive... and basically worthless since dpi can't have more than 600-620hp.

cbbrit · 2 Aug 2019, 20:07 (Ref:3920868)

The Starworks Motorsport Audi R8 LMS was almost last in the first practice session! Th team completely disassembled and rebuilt the car between VIR and RA, but so far is still lacking speed:

https://racerdigital.files.wordpress...practice-1.pdf

**joeb** · 2 Aug 2019, 22:26 (Ref:3920883)

Acura dominated practice 1 (with Nissan up there too), but for second practice things seem a bit more close. Lots of teams have tested here previously, so they should have an idea on the setup. Still expect to see a time in the 1:49's for qualifying.

Practice 1

Practice 2

**joeb** · 2 Aug 2019, 22:44 (Ref:3920886)

Quote:

Originally Posted by cbbrit

The Starworks Motorsport Audi R8 LMS was almost last in the first practice session! Th team completely disassembled and rebuilt the car between VIR and RA, but so far is still lacking speed:

https://racerdigital.files.wordpress...practice-1.pdf

Lowest top speed for the starworks car also.

top speeds

broadrun96 · 2 Aug 2019, 22:55 (Ref:3920887)

Quote:

Originally Posted by joeb

Lowest top speed for the starworks car also.

top speeds

They've been slow all season, even compared to the few other R8s that have run. Audi swears it's fine but something must be truly screwed up with that chassis after they've rebuilt it multiple times this season. Think we'll see them pack it up after this race and pursue another program if they want to race still. It will be sad to see another team head off but can't say I can blame them at all

chernaudi · 2 Aug 2019, 23:54 (Ref:3920891)

I'm surprised that they didn't just buy or rent another R8 to see if it's a problem with that particular car. You'd have to assume that there's some defect with that car or Starworks has badly missed the set up.

**Adam43** · 3 Aug 2019, 00:31 (Ref:3920895)

I don't know, but is that within the feasibility of Starworks budget? And wouldn't you exhaust everything else first?

I mean it's the first thing I try. A slow lap, I whip out the check book and get another car. However it might not really be on for them?

**joeb** · 3 Aug 2019, 03:18 (Ref:3920914)

I was wondering if we were going to see a track record this weekend, then I looked it up. No we are not. Audi R10 had a 1:46.9. and real track record is Dario Franchitti with a 1:39. That's fast. I think this years Indy race was around a 1:40 as well.

broadrun96 · 3 Aug 2019, 14:22 (Ref:3920976)

Quote:

Originally Posted by joeb

I was wondering if we were going to see a track record this weekend, then I looked it up. No we are not. Audi R10 had a 1:46.9. and real track record is Dario Franchitti with a 1:39. That's fast. I think this years Indy race was around a 1:40 as well.

Colton put it on pole as the only one in the 42s at 1:42.992. I don't think they will get too close unless the hybrid really adds something or they really upgrade the tires.

**joeb** · 3 Aug 2019, 16:15 (Ref:3921001)

Quote:

Originally Posted by broadrun96

Colton put it on pole as the only one in the 42s at 1:42.992. I don't think they will get too close unless the hybrid really adds something or they really upgrade the tires.

Third practice just saw both Penske cars below 1:50. Porsche led gte followed by BMW.

cbbrit · 3 Aug 2019, 16:58 (Ref:3921003)

Quote:

Originally Posted by chernaudi

I'm surprised that they didn't just buy or rent another R8 to see if it's a problem with that particular car. You'd have to assume that there's some defect with that car or Starworks has badly missed the set up.

Mr Chase bought the two ex-Stevenson Motorsports cars when the team folded at the end of the 2017 season. So unless they've sold the second car which they had on display at all the PWC races in 2018, then that car should be available!

**joeb** · 3 Aug 2019, 18:06 (Ref:3921011)

looks like a few raindrops for qualifying.

**joeb** · 3 Aug 2019, 18:10 (Ref:3921012)

In GTD qualifying it looks like there is good diversity on the top of the grid
1) Mercedes
2) Lambo
3) Maclaren
4) Porsche
5) Acura
6) BMW
7) Lexus
10) Ferrari
13) Audi

**joeb** · 3 Aug 2019, 18:34 (Ref:3921016)

GTML times were nearly all below the class record for the track. Porsche had one lap thrown out for track limits at turn 1, and Ford is close, no word yet.

edit: ford's time was also thrown out, so they are down the order now.

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