Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Search found 1908 matches

by Orr89rocz
Fri Nov 20, 2020 7:50 pm
Forum: Engine Tech
Topic: How much does moving the cam affect peak rpm?
Replies: 18
Views: 1045

Re: How much does moving the cam affect peak rpm?

Doesnt it depend on how close the cam is to being “correct” for the application and desired performance? If cam was spec’d right it should do the power and rpm you want and moving it a few degs shouldnt change much. If its out in left field moving it may show greater changes. At least thats what i h...
by Orr89rocz
Fri Nov 20, 2020 1:57 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2004

Re: Small cams on 106-108 LSA’s

I recall gm’s 305 tbi “peanut” cam being a 178/194 at .050 and 109 lsa 106 icl. With tpi and the bigger 207/213 117 lsa cam it made alot more power but i think the off idle torque on the old tbi motors wasnt terrible by any means. Always was curious how those motors would do with a much tighter lsa ...
by Orr89rocz
Fri Nov 13, 2020 8:41 am
Forum: Engine Tech
Topic: Question about EFI cold start AFR
Replies: 54
Views: 1180

Re: Question about EFI cold start AFR

Also note it is very common to add 2-4 deg timing during this time and idle speed demand being set few hundred rpm higher. Warm idle 25 deg and 800 rpm, cold starts may be better at 27-28 deg and 1000 rpm until it warms up Here’s a question. I can see why adding timing in cold weather makes sense i...
by Orr89rocz
Wed Nov 11, 2020 11:20 am
Forum: Engine Tech
Topic: Question about EFI cold start AFR
Replies: 54
Views: 1180

Re: Question about EFI cold start AFR

If the fuel is a return style system then going thru the rails mounted on a hot engine it will heat up Also, from all the engines i have seen and some i have tuned from sbc, bbc, lt1 and some ls vehicles, they all seem to want to be a touch richer cold and closer to stoich warm. Some seem to run sli...
by Orr89rocz
Tue Nov 10, 2020 10:10 am
Forum: Engine Tech
Topic: BBC heads question
Replies: 8
Views: 319

Re: BBC heads question

So i used a set of AFR 335 CNC heads for a number of years on my 555 BBC. They worked good and i think the motor was making about 850 hp according to my math. I took the motor apart to fix a spun bearing this fall and i decided to sell / upgrade some of my parts. I sold the AFR heads for a really g...
by Orr89rocz
Wed Nov 04, 2020 7:44 am
Forum: Engine Tech
Topic: Question about EFI cold start AFR
Replies: 54
Views: 1180

Re: Question about EFI cold start AFR

The fuel enrichment should be just enough to compensate for the poor fuel evaporation due to cold temperature. That would depend on the fuel distillation curve and ambient temperature. Fuel evaporation will lower inlet air making fuel even harder to evaporate. I richen mine up so that its just lean...
by Orr89rocz
Wed Nov 04, 2020 7:41 am
Forum: Engine Tech
Topic: Max lift with GM dogbone roller lifters
Replies: 25
Views: 957

Re: Max lift with GM dogbone roller lifters

Well just look at the many hundreds of cammed ls motors out there on hydraulic lifters turning 8000 and less rpm. Light valvetrain, proper lobes matched with proper springs you can do a lot. The “LS7” lifters became the gm replacement for a long time. A lot of guys are going to Johnson lifters for d...
by Orr89rocz
Mon Nov 02, 2020 7:50 am
Forum: Engine Tech
Topic: Max lift with GM dogbone roller lifters
Replies: 25
Views: 957

Re: Max lift with GM dogbone roller lifters

I have used gm ls7 lifters in a sbc oem roller block with a .383 lobe. Worked fine to 7000 rpm
by Orr89rocz
Thu Oct 29, 2020 1:05 pm
Forum: Engine Tech
Topic: 383 sbc, LT4 HotCam cheap gas question.
Replies: 17
Views: 1267

Re: 383 sbc, LT4 HotCam cheap gas question.

Hot cam is nice for alot of mild builds. Been in cars with that cam in 350 tpi builds, lt1 builds and a 383 cam only lt1. Always works well

I dont think 1.6 rockers will change much in the tune or idle quality.
by Orr89rocz
Mon Oct 12, 2020 2:17 pm
Forum: Engine Tech
Topic: Port volume dyno testing
Replies: 11
Views: 1111

Re: Port volume dyno testing

The volume itself is meaningless without other data to go with it. Its a system Of components, so without the information of all components you cant make a reasonable guess on what the results will look like
by Orr89rocz
Mon Oct 12, 2020 8:37 am
Forum: Engine Tech
Topic: Port volume dyno testing
Replies: 11
Views: 1111

Re: Port volume dyno testing

Read the comments, there is a good one somewhere. After the vid was posted, I went to comment myself and saw one that pretty much covered it. Basically says testing nothing but port size is not ideal when other things would be changed to make the most of different size ports. For example if you too...
by Orr89rocz
Fri Sep 18, 2020 7:57 am
Forum: Engine Tech
Topic: MPFI with 16 injectors
Replies: 11
Views: 323

Re: MPFI with 16 injectors

Yeah, why not do it right and run a complete efi system like holley dominator. It will control and phase in the secondary injectors just fine
by Orr89rocz
Wed Sep 16, 2020 2:21 pm
Forum: Engine Tech
Topic: Comp Cams Dual Conical SR Valve Springs
Replies: 23
Views: 2312

Re: Comp Cams Dual Conical SR Valve Springs

Any one else use these 7245 conicals? I have only found some mag articles on a bbm using a rather aggressive 266 deg .473” lobe lift cam to 7500 rpm on a 2.19” valve and the ls motor that was spun to 10000. I like the concept although pricey Worked extremely well on a set of Higgins Ford heads. htt...
by Orr89rocz
Wed Sep 16, 2020 2:17 pm
Forum: Engine Tech
Topic: Throttle response EFI: TBI vs. MPFI on 800 hp BBC
Replies: 6
Views: 236

Re: Throttle response EFI: TBI vs. MPFI on 800 hp BBC

Steve morris did a similar test using holley sniper throttlebody and port efi on same intake and used the sniper tb on the port injection test, just disconnected the tbi injectors. Port made more power everywhere above 4200 to 7500 ish. It was a 733 hp deal. Tbi was down alot in the 5000-6000 range ...
by Orr89rocz
Wed Sep 16, 2020 12:55 pm
Forum: Engine Tech
Topic: Comp Cams Dual Conical SR Valve Springs
Replies: 23
Views: 2312

Re: Comp Cams Dual Conical SR Valve Springs

Any one else use these 7245 conicals? I have only found some mag articles on a bbm using a rather aggressive 266 deg .473” lobe lift cam to 7500 rpm on a 2.19” valve and the ls motor that was spun to 10000.

I like the concept although pricey