Bische

Hello, my name is Bische and im coming from the Audi scene.

I want to build a high CR 1.8t(which isnt usual in the Audi scene) and wanted to hear your thoughts.

My plan is to bore it to 1.9l and run 10.5 static compression with e85. The goal is a responsive powerband, not peak power. Audi heads are not famous for their flow, so i want to take advantage of that and make a wide threshold of power.

I see theres a few such builds over here, im not aware of one single 1.8t that has gone beyond 10:1.

What are your impressions? What boostlevels are you running? Peak timing and peak torque timing? What IATs/EGTs are you running?

Thanks

escodotcarter

iTrader: (16)

I'm sorry.....What does this have to do with Evo 1-9 Engine/Turbo/Drivetrain section?

Bische

In which section do you guys talk about engine builds and their specs then?

Kracka

iTrader: (49)

Nothing...moved to "other cars" section.

Bische

I dont get this.

I came here to ask for first hand experiences with high compression turbocharged engines and a specific fuel. Since i know there is many people here that have done this, i simply started a thread for these questions.

The reason i wrote about my own plans, was for people to know why im asking about it. I did not come here to talk about AUDI's, i came here to talk about YOUR builds and peoples impressions tuning EVO's this way.

If my topic, post or choice of forum section is not right, i will be happy to edit it.

WHTEVO

iTrader: (18)

I am running a "high" CR engine close to what you are wanting to do. I use E85 and running 60psi of boost. Right now i am only running a little over half that but will be turning it back up since i changed a few things to better use the airflow. Good luck.

Aaron

NFSLancerRA

iTrader: (8)

Man, that car must make like 1000 HP and 85 ft/lbs of torque.

JohnBradley

iTrader: (30)

I think he meant half the boost not half the compression.

Biche,

Some answers to your questions but keep in mind our cars run between 85mm and 87mm bore so our timing numbers might not be the same as yours would need to be.

MBT- 18-19*
Nominal EGTs- 1150 to 1200*F
Boost level- 38psi

My car when it made 794whp on a 3586 was 7* at 6k (near peak torque) but it was lit off at 5k. I kept the timing lower at 5000 to maintain traction though so I find that number to be mostly irrelevant. Normally I would be 0-1* there I was -4*. It was 18* out the top.

I switched to the 3794, turned the boost to 39.5psi, ran 4* more timing (11* at 6000) and only 15* out the top to keep from cracking cylinder walls. My motor for next year will be solid so this wont be a nagging concern. At 18-19* there was probably another 40whp in it but as it was it made 831whp.

Mikey (BlkcarbonEvo) has the same motor to the T with the exception of 10.5:1 compression. On an FP Black (essentially a 3582HTA in a stock appearing housing) we ran the same timing numbers out the top but 4* at peak torque with no consideration to maintaining traction. This yielded 748/581 at 41psi.

I have found that the compression is worth 3-4% per point as the old hot rod rule states but the timing on e85 doesnt really change. I personally only run a 9:1 motor as I do like to go back and forth between petrol and ethanol occasionally. I almost did next years motor as an 11:1 (had the pistons on the shelf) but decided to do another 9:1. In our 1G racecar that runs 8.3s we have had everything from a 8.5:1 to an 11.3:1 but in order to keep the noise down (using AEM) we found that the timing pulled to keep a headgasket on it at 45-48psi evened out to the same power and wasnt any faster out of the hole or spooled any faster on the converter. Higher compression only makes a stronger all motor setup but seems to be a curse on turbo engines pushed to the limit.

What turbocharger and how much boost are you planning?

Aaron

Bische

Thank you for taking your time, amazing builds

That is two good comparations, i really like reading numbers like 41psi on 10.5:1! What kind of IATs are you guys seeing at these levels?
I assume there is dyno graphs on here showing these numbers, i will search them up as i am very interested to see what the curves looks like.

These are drag cars right? Is there anyone on here that has build a more track oriented motor?
Say if one would favor timing a little bit, say 10-15* at peak torque ramping to 20-25* at peak horsepower. And instead of running up to 40psi of boost, say 25-30psi?
Would not that not make for good responsive engine character?

How do you feel about running high static CR with a more aggressive cam(like "stock" NA cams, not super aggressive) with a little bit of overlap?

HTA2868r:




A garrett 28series fitted with a FP 68 HTA comressor wheel. .64 turbine housing.

I was thinking around 30psi on e85.

Thanks, Bische

NFSLancerRA

iTrader: (8)

I was just messing with him.

JohnBradley

iTrader: (30)

We use stock ECU in our cars so IAT is not used for how I do SD calculations. In the Eclipse drag car I mentioned the AEM recorded 145* post intercooler (6" ETS core) with the GT42R-HTA at 48psi.

Our setups are more drag oriented typically but I have made numerous pulls into 5th gear for an extended period of time. Our cars wouldnt last at the timing numbers you list. MBT is 18-19* so running 25* would be 7* past MBT and would lead to engine failure. 10-15* at peak torque is subjective. On my car where peak torque is deliberately past 5252rpm then yes you can get away with it. If peak torque on your motor with the turbo that small, I would think it will hammer out rod bearings rather fast.

I made a pull at 14* at 6100 rpm (my artificial torque peak) and made 600 ft lbs at 37psi. I took 3* out and turned the boost to 39.5 and made the 630 ft lbs listed in my signature (FP3794 instead of the 3586).


The most we can run is around 7* at 30psi and that compression before either the bearings take a beating and are done or the headgasket lets go. We did experiment with static timing on a 9:1 motor but it led to eventual headgasket failure. This was done on a car that made 557wp at 32psi, 2.0L, HTA3076, 9:1 compression and 18* from light off (4k) to redline. It lasted 3 or 4 pulls this way. We may have been able to get away with it on methanol but that is not something I am interested in testing on a road car.

Let's back up and discuss whats normal timing numbers on E85 for this motor on normal compression of 8:5:1 to 9.5:1. What would you normally see on pumpgas at peak torque (rpm is a deciding factor so include it please), on racegas/E85 at peak torque, and timing at peak power on both pumpgas and racegas or E85.

I can tell you from my experience with ethanol and the mitsubishi motors, timing will be near what they would be on pumpgas at high boost when you switch to E85 and higher boost (compression seemingly independent) and then ramp up toward 3/4s max engine speed where it would be almost full timing (MBT) and then MBT by redline or before.

Something like this log from my car (this is from the 3586 I mentioned back in my first post)-



refresher- 9:1 compression, 86.7mm x 100mm, 156mm rod length, boost as listed. Cams and headwork specifically intended for this level.

Chu's Mom

iTrader: (6)

Aaron, you're getting me all depressed. I have a 10.5:1 LR2.0 and I plan to max out my HTA3794. Sounds like you're saying if I try it I'll blow the motor since its not a solid block

JohnBradley

iTrader: (30)

No. What I am saying is be careful when you go to max it out. Dave had said awhile ago that above 800whp the cylinders start to move around. I initially though he meant 800 DJ and then thought about it and more likely he meant 800 on his Mustang. This is about 900 on our DJ so it is what it is.

A big motor makes the power easier, so if I had put the 3-4* in and then upped the boost past 40psi I am pretty sure I would have had issues with the sleeves or the headgasket as I run a 2.4L. Maybe I being a girl but I liked 830+ as is and didnt need a broke motor.

Aaron

Bische

I guess since this thread still is in "other cars" i will post some Audi numbers. This is really interesting with the ignition timing(and you have brought up some good points i have not thought about).
Ignition timing on Audi/VW 1.8t's is very different from the EVO's from what i have seen in this thread and skimming through some interesting threads on here.

Here is a short 3rd gear log running Unitronics BT software(considered "good" timing, not aggressive), 28psi tapering to 25psi on a gt3076, 9:1 CR, 93oct




Here is a more aggressive log, Tapp 93oct software. I think this car is 9.3:1 but on a gt3071 running 23psi, 93oct:


GT2871 eliminator, 24psi 93+meth, 9.3:1 CR:


This is a graph of a car running e85, 30psi on a k04(full boost at 3000rpm), 9.3:1 CR. This car is running 93 software that has been tweaked to run e85, so it has 9* added across the board. The owner says it can have some more timing up in the rpms, but since he can only tweak it by adding across the board, he is limited by running MBT at peak torque.


It is concidered safe to run about 10* at torque peak around 4500-5000rpms on straight 93, garrett 30series at around 30psi, 9.3:1 CR on a 2008cc stroker.
That is a common big turbo spec in the Audi/VW scene.

There are not many people running e85 in these engines, so there is little info to get. And tuning for MBT isnt even talked about, most people are running 93+meth and are likly not reaching MBT before they start to detonate.

JohnBradley

iTrader: (30)

Bische,

Looking at your initial log it looks like the timing jumps around a little but more or less it starts at 9.8* (the 10 you mentioned) and finished off at redline near 20? This was 28psi on the 3076 so I dont confuse you. I should have a few logs of very similar builds but off memory I would be 0-1* at 28psi at peak torque and then around 12-13* by 8k at 25psi.

I will dig through my log library and find something that shows what I am used to seeing so maybe we can come up with some parallels.

Aaron