I guess lag is in the eye of the beholder. I have a built 2L with an MAP EF4 Turbo. Now with the right supporting mods this thing is an up top animal. Just wanted to get some insight on others definition on lag. Right now on 93 octane my 9 pulls at 31PSI from 5000rpm to 8500rpm. Thats not lag to me, its raw power, i may just have to downshift to get there, or sit on my 2 step just like anyone with a small turbo would.

 

It sounds laggy to me. But that doesn't mean it isn't fun. haha. Anything where you floor it 3500rpms in 2nd gear and you can keep your head off the seat for like 3 seconds is laggy. IMO. that doesn't mean i wouldn't take your setup.

 

Laggy, when the rt foot drops and your jaw doesnt... the gap between applying pressure the to the gas peddle and the actual acceleration intended. I dont want to wait until 5k to have power, I want it instantly-- how long you are willing to wait for the rush is lag time.

 

Iceman i see where your coming from, i plan on stroking my motor out and switching to E85 soon,but i just see all the threads about big turbos being laggy. Well if i downshift to 1st gear at 35 miles an hour or 50 mph in 2nd gear, we are at 31 PSI in 1 second. My point with the thread is basically if you want biiiig power you got to lose some bottom end. You obviously counteract that by building a higher compression car, but if someone wants to go out and throw a big turbo on their car. They may save a little more gas mileage than the guy thats hitting 27 psi at 3200 rpms, and still have plenty of capability to still pull big numbers at the track.

 

If you can downshift you dont have to worry about lag. I guess we are only talking about driving from redlight to redlight. If im on the highway and i decide "hey lets get on it" im gonna downshift right into the meat of my powerband. 3500 rpm's is plenty in between each gear. atleast for now, till i go higher compression.

 

higher comp is gonna help have better transient response and drivability, but it won't on its own have any dramatic effect on the actual spool up of the turbo.

If you have a turbo thats laggy for big HP, going from 9.xx/1 to 10.5/11+ isn't going to make a big difference in when that turbo spools provided everything else is still the same.

Displacement and turbo/manifold setup will be your bff if youre on a quest to reduce spool up time.

 

Hypco that was the first issue i had to deal with, with the big turbo. Stock intake mani was terrible. Didnt breathe up top at all, so at the time my power band was like 6000 to 7200 rpm's. I was so frustrated, i knew i needed a big intake manifold and some Heavy duty cams so i got rid of my Kelfords and went with GSC S2's. Now before i go higher compression im gonna go from my single 255 to a double pumper, get rid of my FIC 1100 cc injectors go with some 2150's and start using some corn feed(E85) see how i like it then. Im perjecting with more fuel should be around 600 to the wheels.

 

Anything with full boost at 6k is lag lol

 

yeah 6k was laggy it was more of a kill switch at 7200 rpms that did it. 6K was a prime example of too much turbo at the time. And as far as displacement that was what i was referring to earlier in the post with stroking the motor out

 

"Lag" to me is anything that hits full boost past 5,000. More importantly, if it doesn't have a power band that's at least 3,000 rpm then that makes it completely worthless IMO. My buddy has a built STi with a 35r and at our elevation (4,800 ft) it hits full boost at 4,700 rpm and pulls all the way to his shift point (7,500-8,000). When he let me drive it, I put it in 3rd at around 50 mph and mashed it and pretty quickly it was pulling enough to scare me haha. Personally I hate how quick the stock turbo spools on our cars so I am switching to a 6466 on a 2.4 lol.

 

completely agree ct9. You need a 3000 RPM powerband atleast. hopefully when i switch to E85 i can get down to 4500 or 4600 and pull to 8500. I may like it so much ill keep my 2.0,lol.

 

I'm building a similar set up on a 2.0 sleeved MAP block with an EF4 and E85. I have GSC S2 (274/274) cams. I'm not sure what my spool time will but I sure am hoping for 4000 rpms or a little higher. I'm also going E85, not sure if that helps spool time. I know I will be making mid to high 500s. Any thoughts?

 

AJ's on E85 i know that you willl be around 4500RPM frame , but. Im making 517 on 93 octane, so im sure you will be close to 600 whp atleast. With that ported head def, you need to get rid of that Rev 2 mani and get a Rev 3, especially with that turbo. I did, and was shocked at the diff. In fact right now i bet that rev 2 is a big restriction of the power you have now.

 

Lag to me is most noticeable on the street rather than 1/4 mile scenarios. I think lag is lack of torque after hitting the go pedal. I didn't realize it, or didn't want to, but now with the 2.4 and having almost 400 ft/lbs by 3500rpm it gave me a new realization of lag, or what it was

 

Word. 2.4 eclipse block. Got a buddy with a fp green and 2.4. Its an animal. We are talking over 500 whp with over 500 tq. amazing. Anyway yeah torque is a factor for sure,but its one of those things. you see alot of guys running high horsepower too with really low TQ. That must feel SOOO weak. I say lets get a happy medium high horsepower safe tq levels. 2.4, E85, ported head EF4 650 WHP. Sounds good to me with about 500 TQ.