Forza Motorsport

Got it in the next Builders Cup event. Forza Edition cars to count towards this achievement as well as long as you don't upgrade them - I wasn't sure at first but they do

I restarted the first series just because then read this achievement. I ran full B class car for the first race, then ran stock for the 2nd and 3rd. I think you only need stock car at the end of the series for the achievement to pop.

Finished the second championship in first with a stock supra and won the achievement.

If you don't feel like doing the practice races you can skip them. I can confirm the Cheevo will still pop. Just start the practice and hit pause and go down to exit and you will see skip practice. Just make sure you don't hit the upgrade button when going to the next race.

Used a Forza Edition car in Practical Performance, no upgrades, didn't pop :-(

@T3stercles That's because a Forza Edition can from the get-go is not a stock car.
All Forza Edition cars are modified versions of themselves.

Mines wasn't working done it first time nothing second time just now it popped thank god hahah

2nd try: intro cup, no tutorial, 1 run start to finish, brand new car & never entered upgrade window

I've done this perfectly at least 7 or 8 times and no achievement. This game is so bugged and glitchy for me it's insane...

I've done this perfectly at least 7 or 8 times and no achievement. This game is so bugged and glitchy for me it's insane...

I did the Builder's Intro again this time with a Toyota Supra stock as it's one of the fastest cars in B class. Turned the AI difficulty down to 0 and Penalties off and also incresed my starting grid position up to 7th. Verrrrry easy achievement. Even lost connection to the servers between races and still unlocked the achievement first try.

I just completed this first try.
1. Purchased 2018 Honda Civic Type R.
2. Set AI to 1.
3. Skipped practice.
4. Starting position 7th.
5. Finished all 3 races in first.

No need to re-do the first story. Do any story series in the first section without upgrading your car at all. I just got this in the 3 section of the first series (Super Sedans maybe?) with a stock BMW. I bought it and raced the 5 races without ever doing any upgrade to the car. Popped after finishing my 5th race and closing out that section of races.

how do I know which is a stock car?

Just buy a car and do nothing to to in the performance and tuning section. Buy it and go straight to race each time. That is a “stock” car.

Just don’t use your upgrade credits.

Still bugged, completed three different series with stock car no upgrades but it won’t pop

Got it doing the showcase event at the end of the first series. Got awarded a Ford GT for finishing the series, used it in the showcase for just 1 lap of Le Mans (skipped the practice) and it popped at the end, took about 4 minutes.

If you don’t have a connection to the server when you finish the last event you will not get the achievement. It will also not show you getting the trophy. Worse, when you next start the game it will show the last event has not been completed (you have lost progress).

First time I got 3/5 events completed. After repeating event 4 and 5 I got 4/5. After repeating event 5 for the third time I got a Gold Trophy and the achievement. The really stupid thing is that it now shows I have 3 trophies for a tour that I have only completed 1 series in.